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Title: Secondary Stage Biology Book 1 For Class 9
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Biology
Sindh Text Book Board, Jamshoro
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1
Biology
Sindh Text Book Board, Jamshoro
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mynoteslibrary
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Chapter 1
INTRODUCTION TO BIOLOGY
Biology, the study of life is the most vital and challenging branch of science
...
This field is
ever growing, as old questions are answered and new questions are raised
...
They are using this acquired
knowledge of the basic natural processes for the welfare of mankind
...
Relationship of biology with other sciences
...
Contribution of medieval are recent Muslim and other Biologists
Islamic and other views about origin of life on earth
...
It emerges from our curiosity about ourselves, the world and the
universe
...
Natural world
cannot be understood with out asking questions, like how did variety of living
things evolve on earth? In what way they interact? What processes must occur in
each organism? Why living things differ from non-living? Common questions like
these form the basis of the science of biology
...
1
WHAT IS BIOLOGY?
On your way across school campus take a moment to look around you
...
g
...
In addition to the countless tiny ones
...
The word biology is
composed of two Greek words bios meaning life and logos meaning discourse,
thought, and reasoning or in simply the study
...
Biology is further
divided into two main branches i
...
Botany and Zoology
...
According to the revised classification system all the small, usually,
microscopic organisms which were previously classified as plants or animals have
now been separated into independent groups
...
The study of biology provides information about:
1)
2)
3)
4)
5)
6)
7)
Various kinds of living organism existing on earth
...
Identification and grouping of living organisms on the basis of similarities,
dissimilarities and relationship
...
Inheritance of characters from one generation to next generation
...
Harmful and beneficial effects produced by different living organisms etc
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Biology
Sindh Text Book Board, Jamshoro
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2
QURANIC TEACHING ABOUT ANIMALS AND PLANTS LIFE
Almighty Allah has conveyed a great knowledge about animals and plants through
our Holy book the Quran
...
Will they not then believe?"
(Surah Al-Anbiya, Ayah 30)
"And Allah has created every animal of water
...
Allah creates what He will
...
"
(Surah Al-Nur, Ayah 45)
An Egyptian mufassir, Allama Abdullah Yusuf Ali has symbolised water with the
protoplasm and thus explains that the protoplasm is the basis of all living matter
and "the vital power of protoplasm seems to depend on the constant presence of
water
...
Look upon the fruit thereof, when they bear fruit,
and upon its ripening
...
"
(Surah Al-An'am, Ayah 100)
Holy Quran has explained the significance of water for plants and animals at
several places
...
"
(Surah Ta-ha, Ayah S3)
Glorious Quran has also revealed some facts about the growth and variety of
plants
...
And We have
made some of them to excel others in fruit
...
"
(Surah Al Ra'd, Ayah 4)
"Lo! Allah (it is) who splitteth the grain of corn and the date-stone (for sprouting)
...
Such is Allah
...
Allah has also indicated the usefulness of some of the plants and animals to the
human welfare
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Biology
Sindh Text Book Board, Jamshoro
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"
(Surah An-Nahal, Ayah 66)
"And the earth have We spread out and placed therein firm hills, and caused each
seemly thing to grow there in
...
"Glory be to Him Who created all the sexual pairs, of that which the earth
groweth, and of themselves, and of that which they know not!"
(Surah Ya-sin, Ayah 36)
"And thy Lord inspired the bee, saying: choose thou habitations in the hills and in
the trees and in that which they hatch; then eat of all fruits, and follow the ways
of thy lord made smooth (for thee)
...
"
(Surah Al-Nahal, Ayah 68-69)
1
...
Modern biology does not concern only with the recognition and
classification of these species but also deals with their structural and functional
aspects
...
Some of the important
branches of biology common to botany and zoology are:
i)
Morphology (Gr: Morphe = form): This branch deals with the study of
external structural characteristics of plants and animals
...
In plants it deals with the
arrangement of different types of tissues in root, stem leaf etc
...
iv)
Cytology or Cell-Biology (Gr: Kytos = hollow vessel or cell): The
study of structure, function and composition of cell and cell organelles is
called cytology or cell-biology
...
vi)
Ecology (Gr: Oikos = home): It is the study of relationships of living
organisms with each other and with their non-living environment
...
vii)
Embryology (Gr: Embryon = embryo) or developmental biology: It
is the study of progressive developmental changes which occur after
zygote formation upto an organism is formed
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viii)
Taxonomy (Gr: Taxis = arrangement or grouping; Noms = laws
related to naming): It deals with the description; identification,
classification and scientific naming of living organisms, according to their
similarities and dissimilarities
...
x)
Palaeontology (Gr: Palaios = ancient, ontos = being organisms): It
is the study of animals and plants that lived in the remote past and are
now found as fossils in the rocks
...
e
...
In the ancient past
fossil fuel
...
xii)
Microbiology (Micro = very small): It deals with the study of microscopic
organisms such as viruses, bacteria, etc
...
Recently methods of genetic
engineering have brought about a revolution in this field
...
Are
being produced but number of diseases are cured
...
4
BIOLOGY AND OTHER SCIENCES
Biology is a multi dimensional science
...
and these branches
which are related to biology are biochemistry, biophysics, biometry, etc
...
1
...
2
...
One of the sub-branch of biophysics is Radio-physics, where
radioactive isotopes are used to trace the translocation of different
material "in vivo", that is, within the living organism
...
Use of sound waves as ultrasound and laser technology
show
some
relationship
of
physics
with
biology
...
Biometry: It is branch of mathematics where data and measurements
related to living organisms are dealt with
...
All biologists conclude their results by using knowledge of
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Biology
Sindh Text Book Board, Jamshoro
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4
...
5
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Through the
study of life in general, we will learn more about ourselves
...
1
...
In order to resolve a specific
biological problem a biological method is adopted, which consists of following
steps
...
Observation:
Most of the biological investigations start with an observation
...
For example; take the case of malaria
...
Malaria was the one among many other diseases for which a
cure was needed
...
These creatures were later
named Plasmodium
...
Hypothesis:
In the light of observed facts and previously collected information (data)
biologists make 'intelligent guesses' as to what may be the possible answer to
this particular question
...
So, the hypothesis is a statement made by scientists about a certain
phenomenon, on the basis of available information
...
So a
question was raised, is Plasmodium the cause of malaria? It would be a good
guess to say 'yes' but it is only a guess which can be presented as a hypothesis
that:
"Plasmodium is the cause of malaria”
...
Deduction:
To test the hypothesis certain deductions that are logical prediction are made
...
It does not
require any type of experimentation
...
"If Plasmodium is the cause of malaria, then all the patient suffering from malaria
should have malarial parasite in their blood while healthy people should not have"
...
These deductions
can be tested and verified by experiments
...
Experiment:
The next step is to test each deduction (prediction) practically to find out whether
or not the hypothesis is correct
...
This is where the scientist shows his skill as an experimenter
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purpose, scientist performs two types of test i
...
control and experimental groups
...
Both groups were kept in identical conditions
...
5
...
These results verified the deduction and finally the hypothesis i
...
"Plasmodium is the cause of malaria"
...
Theory:
It is not always possible to confirm a hypothesis immediately
...
As more and
more evidence come to hand, the hypothesis gain increasing acceptance and
eventually is promoted to the rank of a theory: A theory is a set of scientific
assumptions consistent with one another and supported by evidence, but not fully
proved e
...
theory of evolution
Thus a biologist studies a problem in a sequential manner through observations,
questions, hypothesis, deduction, testing or experimentation
...
A cautious attitude
expressed in the form of criticism and further tests are performed until a
satisfactory answer is obtained
...
These results must be repeatable that is they should
be obtained by any one doing the same procedure
...
6
HISTORY OF BIOLOGY
The history of biology goes back to the ancient and pre historic time
...
Individual like Aristotle (322-384 B
...
He wrote a book "Historia Animalia"
...
e
...
The Phrastus, discovered sex in plants and described about five hundred plants
therefore, known as founder of Botany
...
It was not until
the beginning of the Muslim period, nearly a thousand years later that
revolutionary developments occurred not only in biology but in the science in
general
...
The most outstanding contribution of
Muslim scientists had been the use of experiments for the first time in scientific
study
...
The
following is a modest list of contributions by the Muslim and other scientists
between the 8th and 20th century
...
Jabir-Bin-Hayan (722-817 A
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D), wrote books "Alkheil, Al-IbiL "Al-wahoosh", "AsSha" and "khalaqul Insan", describing structure and function of body parts of
horses, camels, sheep, wild animals and human being
...
He was regarded a specialist of
his time
...
D), wrote book "Firdus-ul-Hikma" having
many illustrations and detailed articles on Philosophy, Zoology, Psychology and
Astronomy
...
described
Al-Farabi (870-950 A
...
D)
...
Al Farabi is the author of
two very well known books i
...
"Kitab-i-Nabatat" and "Kitab-ul-Haywanat" and
Zahravi was famous for the removal of urinary bladder stone
...
D), wrote books like "Kitabul Manazir" and
"Mizanul-Hikma", He explained the phenomenon of vision and corrected the
Greek conception about vision
...
D), wrote books "Al-Qanoon" and "Fil Tib Al-Shifa", about
plants, animals and non-living things
...
Ziauddin Ibn-Baitar (13th century A
...
He
travelled to several countries, observed and studied many species of plants
...
D) described the process of blood circulation in
human body
...
D) compiled a book "Hayat-alHaywan" deals with the characteristics of 1000 kinds of animals
...
He wrote three volumes on this subject in
which he described 130 diseases of the eye
...
Other Biologists:
After 15th century, European and other biologists made important contribution in
the field of Biology
...
D), described circulation of blood
...
Robbert Hook (1665) discovered "cell" the basic unit of living organism
...
D),
developed
methods
of classification for
organisms and gave nomenclature and therefore, called father of taxonomy
...
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Biology
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J
...
g
...
E
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Charles Darwin (1859), wrote his famous book "origin of species" about
evolution of different species through Natural selection
...
Watson and Crick (1953) proposed double helix model of DNA to explain the
function of DNA as heredity material
...
7
IMPACT OP BIOLOGICAL STUDIES ON HUMAN WELFARE
Biology has made an enormous impact on human welfare by improving quality of
life
...
New
discoveries in the field of biology are bringing revolution in medicine, public
health, agriculture, dentistry, veterinary medicine, animal husbandry, land-scape,
horticulture, pest control and other related fields
...
7
...
Man grew different vegetables and fruits to
supplement his diet
...
These successes have been achieved due to
biological researches in the fields of pest control, genetics and biotechnology
...
This helped to overcome the problem of food shortage
...
1
...
2 Improvement of health:
In the field of health, the discovery and development of new medicines, vaccines
and diagnostic medical equipment has been very helpful to man kind
...
The discovery and development of antibiotics
by biologist has played a vital role in improving our general health conditions
...
can
be easily controlled because of" development of vaccines against these diseases
...
Every day new drugs are
constantly being developed by biologists to fight against the pathogenic organism
enabling to solve the health problems of mankind
...
7
...
As a result of this pollution
not only human beings but also animal and plant life is exposed to all kinds of
harmful effects
...
1
...
4 Genetic engineering:
A new methodology referred to as recombinant DNA technology or genetic
engineering has been developed
...
It provides a way by
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Biology
Sindh Text Book Board, Jamshoro
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Genes controlling
the synthesis of important drugs and hormones can be taken from the organisms
in which they occur naturally and placed in bacterium or other type of organism,
from which the product can be recovered conveniently and in large quantities
...
This is very useful for treating diabetes
...
Many inheritable diseases can now be diagnosed in a developing child before birth
...
Although there are many side effects of these technologies yet no one of us wishes to go back to the
days in which large number of people died of epidemic diseases
...
Few
of us are willing to give up technology's gift of private automobile, though we are concerned about the
amount of air pollution that automobile generate
...
8
ORIGIN OF LIFE
1
...
1 Islamic view about the Origin of life:
The Holy Quran throws adequate light on the origin of life
...
Living and non-living are both created by Him
...
A few are quoted below:
"He is the Creator of the heavens and the earth"
...
There is no god but Him, the Creator of all things
...
He is the Guardian of all things"
...
It is stated:
"We did create man from an essence of clay"
...
He first created man from clay,
then bred his offspring from a drop of paltry fluid
...
He gave your eyes and ears, and hearts: yet you
are seldom thankful"
...
The various stages of reproduction have been
described in Holy Quran in following way
...
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e
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It seemed that animals of today are advanced forms of the past
animals who achieved this form after passing through many changes
...
8
...
This was based on such observations as growth of
fungus on pieces of bread and the appearance of maggots on dead bodies of
animals
...
This old belief that living beings can spontaneously develop
from the non-living is termed as abiogenesis
...
The pioneer in such experiments was an Italian scientist named Redi
...
The view that living beings can develop only from other living being is called
biogenesis
...
Experiment No
...
It was noticed that flies gathered around
the dead snakes
...
After about
eighteen days these maggots transformed into pupae
...
After eight days, a fly emerged from each pupa and all flies were similar to those
which visited the body of the dead snakes
...
The flies had laid eggs on the dead snakes
...
Experiment No
...
He put dead snakes in two; pieces
of meat in other bottle and dead fishes in other bottle
...
After a few days, maggots appeared in the open bottles only
...
This showed that if the flies
were prevented from entering the bottles, the maggots did not appear
...
To test this, Redi performed another
experiment
...
3
Some pieces of meat were put in a bottle whose mouth was covered with a gauze
...
Again no maggots
appeared on the piece of meat, even after many days inspite of the fact that
entry of air was possible
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These experiments provide evidence supporting the idea that only living beings
give rise to living beings
...
Needham's experiment:
In 1748, an English Scientist Needham, boiled meat in water, poured this gravy
in bottles and closed their mouth with cork
...
This once again excited the
believers of Abiogenesis i
...
life from non-life (Fig: 1
...
Pasture's experiment:
The argument on the issue of biogenesis and abiogenesis continued up to the
middle of nineteenth century, till Louis Pasture, a renowned French scientist
proved with experiments, that abiogenesis could not occur in the present
environment of earth
...
He took flasks which had long curved Sshaped necks (Fig
...
4)
...
The yeast infusions were boiled in the flasks and let steam released out of the
neck of each flask
...
No life was produced even
after the lapse of several days; because micro-organisms entering along with
incoming air got stuck up in on the curved walls of the glass neck
...
It was observed that micro-organisms were produced within 48
hours
...
He rejected
spontaneous generation
...
1
...
3 Concept of chemical and organic evolutional
The modern view of origin of life stresses upon the idea of chemical evolution and
ties its origin to the history of the earth and the primitive atmosphere
...
About 15 billion year ago, there was a Big Bang
(huge explosion)
...
In time, about 4
...
The Primitive atmosphere of the earth was
rich in Hydrogen
...
It is believed that the earth's atmosphere at
this stage consisted carbon monoxide, carbon dioxide, Hydrogen, Nitrogen, water
vapours and was exposed to intense radiation and electric spark
...
With the passage of time, the atmospheric temperature
gradually dropped
...
Thunder and lightning sparks together with ultraviolet
radiation caused reactions of the atmospheric gases
...
These molecules I came down with rain and
accumulated in the oceans, lakes, rivers and the soil over a very long period of
time
...
This
sequence of chemical evolution was demonstrated in the middle of the 20th
century by some clever laboratory experiments
...
More recent experiments using
electric sparks in laboratory chambers have successfully produced not only amino
acids and sugar but also the basic ingredients of fatty substances and DNA, all of
which are the constituents of life
...
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Life originated on earth more than 3
...
We do not know how life formed, although
the evidence is consistent with the hypothesis that it evolved spontaneously from chemicals
...
What was the first life form like? The first life form, perhaps, was a sphere of
naked protein or RNA and was capable of making its copies (reproduction)
...
There is now general agreement that this first life form respired anaerobically
because the earth's atmosphere lacked free oxygen; it reproduced asexually
...
The first living organism may
have been like viruses
...
This availability of free oxygen opened the way for an explosion of a variety of
organisms in times to come
...
For at least the first 2 billion years of life on earth, all organisms were bacteria
...
5 billion years
ago, the first eukaryotes appeared
...
First inorganic molecules
interacted in a way that organic molecules came into existence
...
Ultimately there arose the first cell a unit
with a membrane
...
The basic underlying concept in this
process is that over a period of time (a very long period) one form gave rise to
another
...
They argued that new forms of life must have arisen from
older ones through variations and that it was something in the process of heredity
which was responsible for variations
...
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SUMMARY
Biology is the study of living things
...
Biology can be divided further into a large number of branches like
morphology, anatomy, histology, cytology, physiology ecology, embryology,
taxonomy, genetics, paleontology, biochemistry, biotechnology, etc
...
The systematic process used in resolving a biological problem is called a
biological method
...
Hypothesis is a guess made by scientist about the solution of a certain
phenomenon
...
Experiment is the practical testing of hypothesis and deduction
...
The old discarded belief that the living beings can spontaneously develop
from the non-living is termed as abiogenesis, and the view that only living
things can produce their own kind is called biogenesis
...
Living organisms had a common origin but, with the passage of time, they
gradually changed and became different from one another
...
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EXERCISE
1
...
Write whether the statements are true or false:
i)
ii)
iii)
iv)
v)
3
...
(a) Deduction
(b) Theory
(c) Hypothesis
(d) Law
Alkheil, Al-Ibil, Al-wahoosh were written by
(a) Jabir-Bin-Hayan
(b) Abdul Malik Asmai
(c) Ibn-al-Haitham
(d) Zia-uddin Baitar
Write detailed answers of the following questions:
iv)
Make a chart to show the steps of a scientific method
...
Galileo discovered the first microscope
...
Study of tiny organism like virus, bacteria, etc is called parasitology
...
Redi was the pioneer scientist who gave the idea of biogenesis
...
Linnaeus developed method of _________ for organisms
...
Biology also provides information about relation of existing
organism with ______ organism
...
______ verify the deduction and finally the hypothesis
...
Name some branches of biology
...
What do you mean by biogenesis and abiogenesis? Also give some
experiments which explain the concept of biogenesis
...
Define the following terms:
i)
Physiology
ii)
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Biochemistry
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Biology
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Observation
iv)
Genetic Engineering vi)
Deduction
Biogenesis
Distinguish between in tabulated form:
i)
Biogenesis and abiogenesis
ii)
Hypothesis and theory
...
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Chapter 2
STRUCTURAL ORGANIZATION OF LIFE
The cell is the basic unit of life
...
All the things that living organism can do are done by its cells
...
Each cell gets food for energy, obtains
oxygen, produces energy, gets rid of wastes, maintains homeostasis and
produces new cells
...
Learning objectives:
Cell as a basic unit of living organism
...
Concepts of light microscopy and electron microscopy
...
Structure and functions of different cell structures
...
Reproduction of cell, different methods
...
Three level of organization in living organism i
...
tissues, organs and system
...
Types of animal tissues, epithelial, connective, muscle and nervous tissues,
structure of these in relation to their function
...
Multicellular organization
...
Frog as multicellular organization with digestive, respiratory, circulatory,
excretory, nervous and reproductive organs and systems
...
All organisms are
made of cells, which behave as basic unit of their structure and function
...
2
...
The question arises here how did biologist come to know that, obviously through
observations
...
(Latin word micro = small;
skopion = to see)
...
In 1665, Robert Hook made an improved
microscope by combining lenses, called compound microscope and examined a
slice of cork under it
...
The cork was made from bark
of oak, so he actually saw the cell-wall only
...
It was found to consists of cells
...
Schleiden (1838) a German
botanist, proposed that all plants are made up of cells
...
He
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From here the difference between plant and animal cell started to establish
...
e animals
cells come from animal cell and plant cells from plant cell
...
Virchow finally gave rise to cell theory
...
The cell is the smallest, basic structural and functional unit of all
organisms
...
2
...
The discovery and early
study of cells progressed with the invention and improvement of visual
instrument, like microscope
...
Resolution
Resolution is the capacity to
separate adjacent objects
...
Resolution improves
as
the
wave
length
of
illumination
become shorter
...
By
increasing
magnification
resolution is disturbed
...
The microscopes first used by scientist, as well as the microscope you use in the
biology laboratory are light microscopes
...
These lenses reflect the
light in a way that the image of the specimen is magnified as it is projected into
the human eye
...
e just 0
...
In 1935, a new type of power full microscope called Electron microscope was
invented by scientist to improve the resolving power of microscope
...
The electron beam increases its
resolving power
...
2 nm, a thousand times improvement over light microscope
...
This image
cannot focus in human eye, therefore screen or photographic plates are used to
review and focus these images
...
1 millimeter (mm) - 10-3 meter
...
1 nanometer (nm) = 10-9 meter
...
But the light microscope has many advantages especially for
the study of live cells
...
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3
BASIC STRUCTURE OF CELL
Cells are of different shapes and size according to their functions
...
In plant cell, cell-membrane is
surrounded by a cell-wall
...
3
...
Therefore, cell is a unit of structure of living organisms
...
All basic functional
activities, characteristic of living things, occur in the cell
...
1
...
It is not found in animal cell
...
In plant cell it is mainly composed of cellulose and pectin
...
These fibers are kept in their position by a
cementing material called calcium pectate (Pectin)
...
Thickness of cell-wall varies in different cells of plant
...
Middle lamella is formed between the primary walls of neighbouring cells
...
Cell-wall provides protection and support to the cell
...
It also performs the function of transport of
material from outside to inside or vice versa, therefore, it is permeable in nature
...
Cell- membrane:
The
cell-membrane
or plasma
membrane
surrounds nucleus and
cytoplasm in all types of cells
...
It can repair itself to some extent
...
The most acceptable model among them is Fluid mosaic model
presented
by Singer and Nicholson (1972)
...
This basic structure is found in all the membranes of
mitochondria, chloroplast etc
...
Cell membrane is a selectively permeable membrane because it regulates
selective movement of molecules
...
This process is called endocytosis
...
Nucleus or Karyon:
Nucleus (discovered by Robert Brown in 1831) is an important arid prominent
structure present inside the cell
...
It may be
spherical or irregular in shape
...
Nucleus is enveloped by a double membrane called nuclearmembrane
...
Nucleus is
filled with a gel like substance called nucleoplasm
...
The
threads of chromatin become prominent during cell-division
...
These structures of major importance
...
DNA plays significant role in the
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The number of chromosomes in the cells of all individual of the same species
always remains constant
...
of Chromosomes
46
26
48
08
16
48
14
4
...
It consists of an aqueous ground substance called cytosol and
granular portion called cytoplasmic organelles
...
It is a site of metabolic reactions like protein
synthesis, glycolysis etc
...
Some important cytoplasmic organelles found in eukaryotic cells
...
3
...
7
...
4
...
Golgi complex
Plastids
Ribosomes
1
...
It is a network of membranous channels or tubules extending throughout the
cytoplasm
...
There are two types of endoplasmic reticulum
...
ii)
Smooth endoplasmic reticulum without ribosome
...
It also provides mechanical support to the cell so that its
shape is maintained
...
2
...
They are set of smooth membranes that are stacked into flattened,
fluid filled sacs or vesicles containing carbohydrate, glycoproteins and enzymes
...
3
...
The inner membrane is folded
...
Mitochondria contain enzymes
which break the food for the production of energy
...
The number of mitochondria in cell relates to
its activities
...
Plastids:
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These are the organelles
which contain different types of pigments
...
11)
i)
Chloroplasts have green pigment i
...
chlorophyll found in leaves and
other green parts of a plant
...
ii)
Chromoplast have coloured pigments other than green found in fruit,
flower, petals and other coloured parts of plants
...
They store food in the form of starch
...
Centrosome and Centrioles:
A rounded structure, the centrosome is present near the nucleus in animal cells
...
12)
...
They form fibrous protein spindle
which help in movement of chromosomes towards poles during animal cell
division
...
Ribosome:
They are granules, rich in ribonucleic acid (RNA)
...
They are found free
in cytoplasm as well as attached on the surface of rough endoplasmic reticulum
...
Vacuole:
They are the fluid (other than cytoplasm) filled sacs surrounded by a membrane
called tonoplast
...
They are concerned with storage of cell sap
...
4
PROKARYOTIC AND EUKARYOTIC CELL
There are two types of cells, Prokaryotic and eukaryotic cells
...
Prokaryotic (pro: before; karyon: nucleus) cell does not possess true nucleus
...
These
types of cells are found in bacteria and cyanobacteria (blue green algae)
...
Eukaryotic (eu: true, karyon: nucleus) cell possesses proper nucleus where
nuclear material is enclosed in a proper nuclear membrane
...
Followings are the differences found between them
...
2
...
4
...
6
...
They do not have many of the
membrane bound structures e
...
mitochondria E
...
Ribosomes are of small size
and freely scattered in
cytoplasm
...
Single chromosome is found
...
mynoteslibrary
...
2
...
4
...
6
...
They have well defined
nucleus
...
Ribosomes are of large size and
present either on endoplasmic
reticulum or free in cytoplasm
...
Respiratory enzymes are
22
Biology
7
...
Sindh Text Book Board, Jamshoro
...
These cells are simple and
comparatively smaller in size
i
...
average 0
...
Bacteria and cyanobacteria are
examples of prokaryotes
...
8
...
These cells are complex and
comparatively larger in size i
...
10l00nm in diameter average
...
2
...
After growing to a certain
maximum size, a cell may undergo the process of cell division
...
This is followed by division of the cytoplasm
...
Thus two daughter cells arise
from a single division of a cell
...
(1) Mitosis
(2) Meiosis
1
...
Although mitosis is a continuous process, its karyokinesis can be divided for
convenience into four phases which are Prophase, Metaphase, Anaphase and
Telophase
...
i)
ii)
iii)
iv)
Prophase:
During early prophase chromatin material condenses and becomes
visible as thick coiled, thread like structures called chromosomes
...
e
...
The chromatids are attached to each other at
centromere
...
The
centrioles are absent in plant cells
...
Each chromosome is attached to separate spindle fibre by
its centromere
...
In this way one set of the chromatids
(each chromatid is now an independent chromosome) move towards
one pole while the other set towards the other pole
...
Each pole receives the same
number of chromosomes as were present in the parent cell
...
In
this way two daughter nuclei are formed in each cell
...
The nucleus of each daughter cell contains the same
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...
In this way the daughter
cells are exact copies of their parent cell
...
It is responsible for
development and growth of organisms by increasing exact copies of cells
...
The production of new somatic cells, such as blood cells depends
on mitosis
...
2
...
Thus it is the
reduction of the diploid (2n) number of chromosomes to the haploid (n) number
...
The process of meiosis involves two consecutive divisions
...
i)
ii)
iii)
iv)
Prophase I: Those chromosomes in the cell which 'are similar to each
other in shape and size are called homologous chromosomes
...
The difference between
mitosis and meiosis starts at this point
...
In each
homologous pair, there are four chromatids, since each member
(chromosome) of the pair has already doubled itself
...
This
exchange is called crossing over
...
The
nuclear membrane disappears and at the same time spindle fibres are
formed
...
Unlike mitosis, it is
the homologous pair and not the individual chromosomes which attach
at separate fibre of the spindle
...
Telophase I: In this phase the chromosomes come to rest at the
poles
...
On
completion of nuclear division, the cytoplasm also divides and two
daughter cells are formed
...
Thus, the first meiotic division reduces the 2n
(diploid-2 sets) chromosomes to n (haploid-half or one set)
...
During prophase, spindles are formed and the nuclear membrane
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...
In metaphase, the chromosomes (each consisting of two chromatids)
arrange themselves on the equator
...
In telophase, the nuclear membrane
reappears around each set of chromatids (now called chromosomes) and the
cytoplasm divides forming two daughter cells
...
Thus
meiosis produces cells (gametes or spores) with a haploid number of
chromosomes
...
When the haploid male gamete (sperm)
fertilizes i
...
fuses with the haploid female gamete (ovum) to form a zygote, the
diploid number of chromosomes is restored (n + n = 2n)
...
e
...
It is due to crossing over which takes place during
prophase I
...
2
...
The question now is how can a cell express itself as an independent living
thing?
You know that some small organisms (Amoeba) are made of only one cell These
organisms are called unicellular organisms
...
Once capable of
independent existence, the cell has become an organism
...
In some cases, cells have
come together to form loose assemblies and live together as a colony
...
Both have laid down
the foundation of multicellular level of organization of life
...
6
...
A tissue consists of a group of cells which are similar in
structure and function
...
1
...
i)
Meristematic tissue: This tissue contains cells which have ability
to divide, so that the number of cells increases and the organism can
grow
...
This tissue is commonly present in root tips
and shoot apex and helps to increase the length of the root and the shoot
by adding primary tissue
...
This tissue is different from meristematic tissue because its cells do
not divide
...
Permanent tissue may be classified into two groups i
...
simple
tissue
and
complex
tissue
...
a) Simple tissue: Simple tissues may further be divided into following type
on the basis of their structure, i
...
Parenchyma, Collenchyma and
Sclerenchyma
...
mynoteslibrary
...
i
...
These cells have intercellular spaces
...
It is food storing tissue
...
Collenchyma: It consists of some what elongated cells with the
corners filled with cellulose and pectin
...
iii
...
They are dead cells
...
They are found in xylem and hard fruit coats
etc
...
These will be discussed later under
conducting tissues
...
These tissues form the outer layer of root, stem and leaf
...
However, in the stem and leaves, pores called stomata are present
through which gases are exchanged
...
ii) Ground tissues: Ground tissues are composed of thin walled
parenchymatous cells, which axe formed from meristematic tissue
...
These tissues are present in all
parts of the plant except the epidermal and the vascular tissues
...
Such
cells make up supporting tissue
...
Sclerenchyma (thick walled,
lignified and elongated) and collenchyma (living cells with thick cellular
walls with few small intercellular spaces) are examples of the supporting
tissues
...
Xylem and Phloem are examples of this tissue
...
The
phloem is made up of living cells like sieve tubes, which conducts food
from leaves to various parts of the plants
...
2
...
Some
important types of animal tissues are:
i)
ii)
Epithelial tissue: The cells of this tissue occur in a single layer and are
closely packed together
...
Epithelial tissue occurs in glands where it is
variously folded
...
They consist of a ground substance, cells
and fibres
...
Fatty tissues are
examples of the soft type
...
Blood is also a special connective tissue with cells
suspended in a fluid medium
...
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26
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iii)
iv)
Sindh Text Book Board, Jamshoro
...
Each muscle
fibre is an elongated cell, which has the ability to contract and relax
...
Nervous tissues: These tissues are formed of cells called neurons or
nerve cells
...
The nervous system (brain, spinal cord, nerves) is
made up of this tissue
...
6
...
All of
these tissues have come together in the arm to make it an organ
...
Similarly, in a plant the root, the stem and the leaves arc organs
...
2
...
3 Organ systems:
Organs work together as a unit to perform a particular function to make an organ
system
...
There are other
systems in the animal body such as transport, respiratory, excretory, muscle,
skeletal, nervous and reproductive systems
...
However, the
systems, here are not so clearly organized as in the animals
...
In this chapter you are studying life at various levels of organization from the
simplest to the most complex
...
7
UNICELLULAR ORGANISMS
Those animals and plants, which are single-celled, are called unicellular
organisms
...
Amoeba:
It is a unicellular aquatic organism found in stagnant water pools and ponds
...
25 millimeter
...
The structure of Amoeba is very simple
...
Cytoplasm is differentiated into two parts
...
The inner viscous, translucent and granular part
is called endoplasm
...
Nucleus is usually present in the centre but as the Amoeba moves, the nucleus
changes its position
...
The food vacuoles contain food particles
...
The pseudopodia are also used to capture food particles, which
enter the body as food vacuoles
...
2
...
mynoteslibrary
...
The majority of living organisms consist of many cells and are called
multicellular organisms
...
2
...
1 Brassica:
Brassica campestris is the botanical name of mustard (sarsoun)
...
Structure of Brassica:
This plant consists of roots, stem, leaves, flowers, fruit and seeds
...
e
...
The vegetative parts are those which do not directly take part in sexual
reproduction
...
The reproductive parts consist of sex organs which are directly related to
sexual reproduction
...
1
...
The first part of the root to arise
from the radicle is known as the primary root
...
The primary roots are thicker than the
secondary and tertiary roots
...
The root bears fine, thin root hairs
...
Internal structure:
The outer part of a root is the epidermis (epi=above; derma=skin), which
protects the root
...
Next to epidermis
is the cortex
...
Parenchyma cells store
food material
...
The
stele of the root is surrounded on the outside by a layer of cells called
endodermis
...
Branch
of the root originate from the pericycle
...
In between the arms of the xylem is phloem
...
ii)
Stem: This part of plant develops from the plumule of the seed and
grows away from the soil
...
The point, on the
stem or on a branch, which gives rise to leaf, is known as the node
...
The stem and
the branches transport water and salts from the root to the leaves
...
In
addition, the stem supports the leaves and the branches in the air, thus
enabling the leaves to receive maximum amount of sun light for
photosynthesis
...
Internal structure:
A cross section of Brassica stem shows that it is surrounded on the outside by a
single layered epidermis
...
The cortex is made up
of parenchyma and collenchyma cells
...
Next
to the cortex is a ring of vascular bundles
...
Xylem is located towards the inside and phloem towards the outside
...
mynoteslibrary
...
called cambium
...
It is made up of
parenchyma cells and stores food material
...
Generally, the leaf of Brassica consists of two parts
...
Young leaves are without petioles and their margins are entire or smooth
but in mature leaves the margin is wavy
...
The branch veins emerge
and spread in the leaf like a net
...
This network of veins supports the leaf
and keeps its lamina in an expanded position
...
The function of the leaf is to
prepare food
...
----------------------------------------The leaves are arranged on the stem and branches in such a way that
their upper surfaces remain directly exposed to sunlight while the lower
surface does not get the same amount of light
...
Leaves
having different upper and lower surfaces are called bifacial leaves
...
The upper layer of a leaf is
called the upper epidermis
...
Each stoma has a pore and
two guard cells
...
The mesophyll cells below the upper epidermis are longer than broad
and are closely packed
...
The cells next to the
palisade layer are irregular in shape and loosely arranged having spaces like
sponge and is called the spongy layer
...
Running through
the leaf are many vascular bundles or veins
...
Xylem is located towards the upper side and the phloem towards the
lower epidermis
...
Reproductive parts
Flower:
With growing age, Brassica plant bears small, yellowish flowers
...
They are arranged on young
branches in a special way
...
Parts of the flower:
The flower in Brassica is situated on a stalk known as pedicel
...
The floral leaves are arranged in four whorls on the
thalamus
...
i)
ii)
Calyx: This is the outermost whorl and consists of four free sepals
...
The most
important function of the calyx is to cover the inner parts of the flower and
to protect them from sunlight and rain
...
Because of the petals, the flower becomes very conspicuous that
honey bees, butterflies and other insects are easily attracted and thus help
in pollination
...
mynoteslibrary
...
Androecium: The androecium lies inside the petals
...
Its parts are not leaf-like
...
In Brassica flower, the stamens are arranged in two circles
...
The inner circle has four long
stamens
...
Each
anther contains numerous pollen grains
...
There are
dark green nectaries of small size at the base of the androecium
...
This nectar is the food
of insects
...
This results in the pollination of flowers
...
The parts of the gynoecium are called carpels, who are the female
reproductive organs of the plant
...
Each carpel is divisible into three main parts
...
Above the ovary carpel extends into a
thin stalk, the style
...
In
the ovary many ovules are present, which ripen into seeds
...
The fruit of Brassica is a long dry
capsule with many seeds
...
They can be
easily dispersed by air currents
...
2
...
2 Frog:
The frog lives both in water as well as on land
...
There is a membranous skin between its toes which helps
in swimming
...
In male frog the first finger is thicker than the
others
...
As the head is directly attached to the trunk
frog cannot move it as we can
...
Behind each eye is a circular area called tympanic membrane
...
At the tip of the snout it has two openings called external nostrils
by which frog breathes
...
It is slippery
due to secretions produced by glands present in it
...
They hibernate during the winter season by burying themselves in the mud and
stay there throughout the winter
...
Internal organs:
The internal organs are located in the body cavity, which is also called coelom
...
These
are as follows:
1
...
This system is
composed of a tube, the alimentary canal and special glands associated with it
...
i)
Buccal cavity: Food enters into the buccal cavity through mouth
...
They are not
meant for chewing food but prevent it from slipping out of the mouth
...
mynoteslibrary
...
the buccal cavity and being free behind
...
---------------------------------------------------------Frog feeds mainly on insects
...
The prey sticks to its sticky tongue
...
Pharynx: The buccal cavity opens into a short but narrow pharynx,
which leads into a wide tube,, the oesophagus
...
When the food passes into the
oesophagus, the glottis is closed and during respiration it is opened
...
Stomach
is a thick walled, muscular and glandular sac
...
Food is grounded in stomach and mixed with enzyme pepsin,
which partially digest proteins
...
Intestine: The intestine is a long narrow coiled tube
...
The partially digested food from the
stomach enters the small intestine through pyloric end, where its
digestion is completed
...
The
undigestible parts of the food enter the large intestine, also called
rectum
...
From
cloaca undigested food is expelled out as faeces through its opening
called cloacal aperture
...
Liver and pancreas: The liver is a large reddish-brown gland
located adjacent to the stomach
...
Between the lobes of the liver is a rounded pouch called gall
bladder, which stores bile
...
On its way, this
duct passes through pancreas and joins the pancreatic duct
...
Its secretion, pancreatic juice, is carried by the pancreatic
duct
...
The
bile and the pancreatic juice help in the complete digestion of the
food in the small intestine
...
The digested food is then absorbed into the blood through the
intestinal walls
...
Respiratory system:
Energy is required by every organism to carry on all the life activities
...
This process takes place in
the cells
...
This entire process called respiration,
divided into two phases
...
We will restrict our discussion upto gaseous exchange as respiration
...
These are:
i)
Pulmonary respiration
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Biology
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...
The frog has two lungs, which are balloon like structures
...
The lungs are richly supplied with
blood vessels
...
The two bronchi
open into a larynx
...
------------------------During respiration air is taken in by the external nostrils
...
From here it enters the glottis,
passes through the larynx and bronchi finally reach the lungs
...
e
...
Aresting
ii)
iii)
human
breathes out
about
500
litres
of
CO2
every 24 hours
...
Frog uses skin as a respiratory organ during swimming and hibernation
...
Buccal respiration:--------------------------------------------------------The lining of buccal cavity is thin, moist and richly supplied with blood
capillaries
...
This type of respiration is called buccal respiration
...
Circulatory system:
Every cell requires a supply of oxygen and nutrient molecules and must get rid of
waste products
...
Blood transports these materials during its circulation through
out the body
...
It consists of:
i)
ii)
Heart- strong muscular pumping organ
...
(b)
Veins － Which return blood to the heart
...
Heart:
Heart is a conical, muscular pumping organ, located in the anterior region of body
cavity
...
It contracts and
expands continuously through out the life
...
Frog heart consists of three chambers
...
Left auricle or Atrium
...
The longest heart stoppage was 4 hours
...
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...
The truncus arteriosus originates from ventral side of the ventricle and divide
into two branches each of which divides into three arches (arteries)
...
Both of these structures are not true chambers of heart but often
called accessory chambers
...
The
oxygenated blood from the lungs enters the left auricle through pulmonary veins
...
From sinus venosus, it reaches the right auricle
...
When ventricle contracts it is
pumped into the truncus arteriosus From here it enter (a) the pulmonary arteries,
which carry the blood to lungs for oxygenation and (b) the systemic arteries,
which supply it to all parts
...
A human being contains about 70 ml of blood per Kilogram of body weight
...
The opening between various chambers of the heart are guarded by valves, which
prevent the flow of blood in reverse direction
...
Arterial system:
A blood vessel, which carries blood away from heart to the various body parts is
called an artery
...
Pulmocutaneous arteries: They supply deoxygenated blood to lungs and skin
where it gives up carbon dioxide and picks up oxygen
...
Systemic arteries: These vessels carry oxygenated blood to all the parts of the
body except the head and lungs
...
5
...
The venous system consists of the following major
components
...
(ii) The deoxygenated blood from head and fore limbs is collected
through several veins, which join together to form one major
precaval vein, on each side
...
Both the pre-cavals and the post-caval open into the
sinus venosus from where the blood is pumped into the right auricle
of the heart
...
mynoteslibrary
...
Portal system: Set of veins, which collect the blood from one organ and
discharge it into another organ, is called portal veins
...
Hepatic portal system: The veins collecting the blood from the digestive system
do not carry it directly to the heart
...
From the liver, blood enters the postcaval, which carries it to the sinus venosus
...
These
veins are also included hepatic portal system
...
These veins begin in capillaries in the hind limbs and
breaks up into capillaries in the kidneys
...
These veins arc
included in renal portal system
...
Excretory system:
It is the set of organs involved in the process of excretion i
...
the removal of
metabolic waste matters from the body
...
There are two kidneys in frog
...
The urine is carried from the
kidneys by a pair of tubes called ureters, which open into the cloaca
...
7
...
Organs
involved in this process are included in reproductive system
...
The reproductive organs consist of gonads and their ducts
...
The male
gonad is known as the testis (plural testes) and the female gonad is called the
ovary
...
The
sex cell of male is sperm and that of female is ovum (Plural ova) or egg
...
The male produces sperms during the breeding season
...
Each sperm fuses with a egg and a new
frog starts developing
...
Nervous system:
The set of organs, which control and co-ordinate all the activities of the body is
called nervous system
...
e the central nervous
system and the peripheral nervous system
...
e
...
The animal with the heaviest brain is the sperm whale
...
2 Kg
...
The brain consists of the following regions:
(i)
The most anterior region comprises the olfactory lobes
...
mynoteslibrary
...
(ii)
Immediately behind the olfactory lobes, there are two large
outgrowths called the cerebral hemispheres
...
(iv) The part between the optic lobes and hemispheres is known as the
diencephalon
...
(v) The last part of the brain consists of the cerebellum and the
medulla oblongata
...
It passes from the skull through a hole and enters the canal of the
vertebral column
...
Brain and spinal cord are not solid
...
Olfactory lobes are associated with the sense of smell and transfer of olfactory
sensation to the cerebral hemispheres, which are the seats of intelligence and
memory
...
The optic lobes are associated with the eyes and vision
...
The medulla also controls respiration, circulation
and digestion
...
The peripheral system connects body parts with the central nervous system
...
Cranial nerves connect and establish
communication between various parts of brain and parts of the head while the
spinal nerves connect structures of the trunk area with the spinal cord
...
Autonomic nerves control the
internal organs of the body such as heart, lungs, stomach, smooth muscles of the
intestine, vessels and glands
...
9 SENSE ORGANS
To get the informations about the environment organisms like frog have receptor
organs
...
The frog has many types of receptors
...
For smell, there are olfactory receptor located in
the nostrils
...
Ears are used for receiving sound waves and maintaining balancing and
eyes for receiving light i
...
sight
...
Using its
antennae, it can detect a female emperor moth 11
...
Its tongue weighed 4
...
1
...
Its outer most
part is the tympanic membrane
...
On the inner side of this membrane is a cavity known as tympanic cavity
...
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...
Human can hear sounds
which vibrate at about 19 KHz
...
The internal ear (Fig: 2
...
It consists of three semicircular canals
...
When sound waves strike the tympanic membrane
it is set into vibration
...
The
internal ear, in addition to hearing, also keeps the balance of the body
...
Eye:
The frog has two eyes one on each side of the head (Fig: 2
...
If we make
vertical section of the eye, we find that the innermost layer of the ball is the
sensory retina
...
Outside the retina is the
choroid, which is richly supplied with blood capillaries supplying nutrients to the
retina
...
It provides shape to
the eye ball
...
Behind the
cornea is iris
...
Behind the pupil is the lens
of the eye
...
A watery fluid is
present in between the cornea and lens
...
Optic nerve takes the sensory messages from the eye to the brain
...
mynoteslibrary
...
SUMMARY
Cell is the basic unit of living organisms
...
Cells are observed under light and electron microscopic
...
Plant cell consist of cell-wall, cell membrane, cytoplasm and nucleus, in an
animal cell all these parts are present except cell-wall
...
Cell wall is non-living part of cell, mainly composed of cellulose and pectin
...
Translucent material filled in between nucleus and plasma membrane is called
cytoplasm
...
Cells divide to increase in numbers
...
Meiosis is the reductional cell-division in which number of chromosomes
reduces to half
...
Amoeba is an example of unicellular organization, Brassica and frog of
multicellular organization
...
mynoteslibrary
...
Sindh Text Book Board, Jamshoro
...
Write whether the following statements are true or false:
i)
Gonads are the organs responsible to produce germ cells
...
iii)
Pulmonary vein contains de-oxygenated blood
...
v)
During pulmonary respiration gaseous exchange takes place
through skin
...
Encircle the appropriate answer:
i)
ii)
iii)
iv)
v)
Nucleus of cell was discovered by
(a) Robert Hooke
(b) Schleiden
(c) Robert Brown
(d) Virchow
The type of lenses of light microscope is
(a) Biconcave
(b) Convex
(c) Concave
(d) Electromagnetic
DNA is found in
(a) Nucleus
(b) Chromosome
(c) Cell
(d) Nucleoplasm
Prokaryotic cells do not contain
(a) Nucleus
(b) Membrane bound nucleus
(c) Ribosome
(d) Cell-membrane
The number of chambers in the heart of frog is
(a) Two
(b) Three
(c) Four
(d) Five
4
...
iii)
Describe those organelles which are only found in plant cell
...
v)
What is the difference between cellular respiration and gaseous
exchange? Describe different methods of gaseous exchange in frog
...
5
...
How do the chromosome number remains the same in the members of
same species?
Why is meiosis called reductional cell-division?
Why is upper surface of dicot leaf much darker than the lower surface?
iv)
v)
6
...
mynoteslibrary
...
x) Compound tissue xi) Mitosis
xiii) Neuron or Nerve cells
7
...
ii)
Cell-wall and cell-membrane
...
iv)
Light and electron microscope
...
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...
To study such a diversified
group it is customary to classify it into groups
...
But
closer examination with better techniques necessitated three more kingdoms
...
Likewise biologists,
rather than dealing with millions of different organisms, classify them into major
groups
...
A classification
system is based on shared characteristics
...
More specific characters result in smaller
groups
...
Learning objectives:
The exact meaning of classification
...
Criteria used in the classification of living organisms
...
Binomial nomenclature
...
3
...
In a
broader sense, taxonomy can be defined as a branch of biology, which deals with
the description, identification, classification and naming of living organisms
according to structural similarities and dissimilarities
...
3
...
It is not always easy to recognize these basic
similarities
...
It is
principally the homologous structure that one considers in grouping organisms
...
Sometimes it is impossible to classify organisms using morphological criteria, so
one may compare the chemical substances which they contain
...
Other characteristics used in classifying organisms
include cytological structures with the help of electron microscope, genetic
constitution and their developmental patterns etc
...
mynoteslibrary
...
3
Sindh Text Book Board, Jamshoro
...
A species is a group of
organisms which has numerous physical features in common and which are
normally capable of inter breeding and producing fertile offspring
...
Similar genera are
grouped together into families, families into Orders, orders into classes,
classes into phyla (singular -phylum) or divisions and phyla or divisions into
kingdoms
...
The name of a species maybe given on the basis of
i) Locality
ii) Character of plant
in) Religious belief
iv) Scientist who first discovered it
For example:
Ficus bengalensis (Banyan tree) named after locality
...
Ficus elastica (Rubber plant) named after that atex is extracted
...
3
...
Linnaeus adopted the binomial nomenclature system for naming organisms to
eliminate confusion while using native or common names when describing an
organism
...
This is
known as binomial nomenclature
...
The species name follows
the generic name and begins with small letter
...
Every scientific name is written in italic or it is underlined
...
5
COMMON SCIENTIFIC NAMES AND CLASSIFICATION
1)
Common name
KINGDOM
DIVISION
CLASS
ORDER
FAMILY
GENUS
SPECIES
SCIENTIFIC NAME
…
…
…
…
…
…
…
…
…
Mustard
Plantae
Tracheophyta
Dicotyledonae
Capparales
Brassicaceae
Brassica
Campestris
Brasica Campestris
2)
Common name
KINGDOM
PHYLUM
CLASS
ORDER
FAMILY
GENUS
SPECIES
SCIENTIFIC NAME
…
…
…
…
…
…
…
…
…
Man
Animalia
Chordata
Mammalia
Primat
Hominidae
Homo
Sapiens
Homo Sapiens
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Biology
3)
Sindh Text Book Board, Jamshoro
...
6 MAJOR GRQUPS OF LIVING ORGANISMS
Two Kingdom to five Kingdom classification:
Previously living things were classified into two kingdoms namely Plant Kingdom
and Animal Kingdom
...
All the living organisms having cell-wall and
chlorophyll were regarded as plants and placed and studied under Kingdom
Plantae
...
But a
large ruimber of living organisms did not fit cleary into the category of plants and
animals
...
Whittaker (1969) suggested a new
system of classifying living organisms
...
1
...
2
...
3
...
4
...
5
...
Although Whittaker's Scheme received wide spread approval, it had one major
draw back
...
Other
problem was that it meant putting the algae into two separate kingdoms, the
protista and the plant kingdom
...
According to this, there are five
kingdoms of living organisms as listed below:
1
...
g
...
2
...
g
...
3
...
g
...
4
...
g
...
5
...
g
...
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Biology
Sindh Text Book Board, Jamshoro
...
The scientific study which deals with the classification of living organisms is
called Taxonomy (Taxis= Arrangement
...
All the living organisms placed in a particular group have many fundamental
similarities in their structure
...
Closely related species are grouped together into genera
...
Linnaeus's system of naming give each species a scientific name comprising
two words is known as binomial nomenclature
...
Now a days living organisms are classified into five kingdoms
...
mynoteslibrary
...
EXERCISE
1
...
The study which deals with the classification! of living organisms is
called __________
...
2
...
Closely related genera are grouped together into classes
...
3
...
i)
ii)
iii)
5
...
Name the five kingdoms of living organisms
...
Why is the kingdom protoctista difficult to classify? What is the basis of
their grouping in kingdom protoctista? Give examples of each of its group
...
Write a note on binomial nomenclature
...
mynoteslibrary
...
Chapter 4
VIRUS, BACTERIA AND CYANOBACTERIA
The most abundant organisms on earth are so small that they cannot be seen
with the naked eye
...
Though structurally simple viruses and bacteria
play an important role in the biosphere
...
Discovery of virus, characteristics, structure, types and the diseases caused
by viruses in humans, other animals and plants
...
Shapes, nutrition and importance of bacteria
...
4
...
They form a heterogenous group which includes
viruses, bacteria, cyanobacteria, protozoa, unicellular algae and some
fungi
...
Rest of the micro-organisms are eukaryotic and studied
under protoctista (Protista)
...
Protozoa are heterotroph
...
4
...
1 Viruses:
Viruses (Latin word Viron = Poison) are the smallest, the simplest and perhaps
the most primitive living things
...
Some diseases puzzled them
...
In 1892,
Russian biologist, Iwanowsky showed that this disease was due to some thing
smaller than bacteria
...
No one had seen them because
they were too small to be seen even with the compound microscope
...
A new kind of microscope the electron microscope had been
constructed and any object smaller than mµ (millimicron 1,000,000,000th part of
a metre) can be observed
...
This TMV and many other viruses
were actually seen with the help of the electron microscope
...
1
...
They cannot live and reproduce outside of living cells since they
lack the ability to do so by themselves
...
They are sub-microscopic
...
They reproduce by replication
...
mynoteslibrary
...
The simple viruses use the enzymes of the host cell for both their protein
synthesis and gene replication; the more complex ones contain upto 200 genes
and are capable of synthesizing, through their host many structural proteins and
enzymes themselves
...
4
...
3 Structure:
They appear like small rods, tadpoles 6r may be polyhedrals or like little spheres
...
Their
nucleic acid may consist of a single or several molecules of DNA or RNA
...
The protein coat that encloses the nucleic acid is called a capsid
...
Capsid is made up of protein subunits called capsomeres
...
Some viruses have accessory structures called viral-envelopes that help them
infect their hosts
...
The simplest viruses consist of a single molecule of a nucleic acid (DNA or RNA)
surrounded by a capsid, which is male up of different protein molecules
...
Each of them is made up of at least five separate proteins: these make up the
head; the tail core, the molecules of the capsid, the base plate of the tail, and the
tail fibers
...
They may be:
Plant-viruses
Animal-viruses
Bacteriophages
infecting plants,
infecting animals and
which infect bacteria
...
1
...
Viruses with their core of DNA or RNA surrounded by a protein coat
somewhat resemble the chromosomes of other living organisms
...
They have the ability to reproduce (Property of replication-reproduction)
...
Many kinds of viruses are known to undergo mutations
...
Viruses show genetic recombination
...
i)
Non-cellular structure
...
iii)
Completely inactive outside host's cell
...
1
...
Animal diseases:
Several of the animal viruses cause many important diseases
...
Although poliomyelitis
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...
Colds are viral infections of the upper respiratory tract
...
Measles and Mumps are the common viral diseases of children
...
Human Immune Virus (HIV) was discovered in 1985 to be the cause of
Acquired Immune Deficiency Syndrome (AIDS)
...
The majority of human viral diseases are spread through respiratory tract by air
borne droplet spread by sneezing and coughing of infectious people or by the
contaminated water and food or by blood or other body fluids
...
2
...
This virus
affects the leaves of tobacco plants and light green and yellow patches appear on
the leaves of diseased plant
...
Therefore, their efforts are focused largely on reducing the incidence and
transmission of such diseases and also on developing varieties of crop that are
relatively resistant to certain viruses
...
2
BACTERIA
Bacteria grow in every habitat of earth under all possible environmental
conditions
...
They can survive in freezing temperature and also in hot sulphur springs
...
Bacterial cell ranges in size from 0
...
(micron) to 2 µ in width and 2 to 10 µ (microns) in length
...
Bacterial cell consists of cell-wall, plasma-membrane,
cytoplasm and nuclear material
...
It is thick and
rigid and made up of amino-acids, sugar and sometimes chitin
...
It has many pores
...
Cell-membrane performs the function of
respiration as mitochondria are absent in them
...
Cytoplasm is granular, present in between cell-membrane and nuclear region
...
It has no
endoplasmic reticulum and no other membranous organelles like golgi apparatus,
plastid and mitochondria
...
mynoteslibrary
...
chromosomes
...
Shortly before a bacterium divides, these DNA bodies replicate
(double) and are equally distributed to the daughter cells
...
4
...
1 Form (Shapes):
There are different shapes of bacteria
...
Kokkos = Berry, rounded)
...
They are non-flagellated
...
They are rod shaped
...
They may be flagellated
...
Sperira = A coil
...
iv)
Vibrio or comma: They are slightly curved or comma (,) shaped e
...
They may be flagellated
...
2
...
Heterotrophic bacteria are
those which cannot synthesize their organic compounds from simple inorganic
substances
...
i)
Saprophytic bacteria:
They get their food from dead organic matter
...
Bacteria living in the soil have large number of
enzymes that break down the complex substances of humus to simpler
compounds
...
Many other saprophytic bacteria cause decay of dead animal
and plant material as they convert complex organic compounds to simpler ones
...
They obtain food from the
host without harming it, e
...
nitrogen fixing bacteria in the roots of leguminous
plants
...
These bacteria lack certain complex systems of enzymes
...
Autotrophic bacteria may be photosynthetic or chemosynthetic
...
mynoteslibrary
...
a) Photosynthetic bacteria: They have pigments very similar to the chlorophyll
and named as bacterio chlorphyll
...
They carry out
photosynthesis
...
Many are
also symbiotic heterotrophs, including those that cause disease
...
4
...
3 Respiration:
Another aspect of metabolism which can be used in the classification of bacteria is
their need for oxygen in respiration
...
Anaerobes respire without oxygen
...
Others use oxygen but can respire without it, they are called
facultative anaerobes
...
4
...
4 Importance of bacteria:
1
...
Nitrifying bacteria
convert the proteins of these dead bodies into nitrates
...
Soil bacteria increase the fertility of
the soil by bringing about physical and chemical changes in the soil
...
Similarly some are present in human
beings and make vitamins
...
iv)
Medicinal bacteria: Valuable antibiotic drugs have been obtained from
bacteria, e
...
Riboflavin is a vitamin produced by
Clostridium
...
Harmful bacteria:
i)
Pathogenic bacteria: They are responsible for most varied kind of
diseases in human beings, animals and plants
...
Some of the diseases found in man due to bacteria are typhoid, tetanus,
cholera, diphtheria, and tuberculosis (T
...
Plant diseases caused by bacteria
are black rots of cabbage, citrus canker, fine-blight of pear and apple, ring rot of
potato etc
...
mynoteslibrary
...
Food spoilage: Bacteria spoil food by fermentation and decomposition
...
3) CYANOBACTERIA (Blue green algae)
Salient features of this group are:
1
...
3
...
5
...
7
...
They may occur alone or in the form of colony
...
Protoplasm is differentiated into an outer coloured region—chromoplasm
and an inner colourless region—centroplasm
...
Total absence of sexual reproduction
...
g
...
Cyanobacteria are photosynthesizers that sometimes can also fix atmospheric
nitrogen
...
NOSTOC:
Taxonomic position: According to new classification, Nostoc belongs to kingdom
prokaryotae(Monera)
...
The filaments are intermixed in a gelatinous mass
forming a ball like structure
...
A single filament look like a chain
of beads
...
Each cell has double layered wall
...
The inner thin layer is made up purely of cellulose
...
There is total absence of endoplasmic reticulum, mitochondria, golgi bodies and
vacuole
...
The centroplasm also called central body have hereditary material (DNA) in the
form of long coiled structure called chromatin body
...
These are called heterocyst
...
But they are specially concerned with the multiplication of
filaments during unfavorable conditions
...
mynoteslibrary
...
SUMMARY
Living organisms which cannot be seen without the help of microscope are
called micro organisms
...
Viruses are the smallest, the simplest and perhaps the most primitive living
organisms
...
They cannot live and reproduce outside the
living cells
...
There are three types of viruses
...
Animal-viruses
infecting animals
...
Bacteria are the most abundant prokayrotes with variety of shapes
...
According to their mode
of feeding, heterotrophic bacteria may be saprophytic, symbiotic or parasitic
...
Others use oxygen but can respire without it, they are called
facultative anaerobes
...
Bacteria are responsible for most varied kind of diseases in human beings,
animals and plants
...
The Nostoc is filamentous
...
It floats on water
...
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Biology
Sindh Text Book Board, Jamshoro
...
Fill in the blanks with appropriate terms:
i)
Previously, living organisms were classified into two kingdoms
namely Plant Kingdom and ________ kingdom
...
iii)
Kingdom Protista has been renamed as ________
...
v)
A single filament of Nostoc look like a _______ of beads
...
Write whether the statements are false or true:
i)
Kingdom Protoctista includes all the eukaryotic organisms,
which are no longer classified as animals, plants or fungi
...
iii)
Electron microscope was constructed in
...
iv)
Virus mainly consist of capsid and Nucleic acid
...
3
...
(a) Noncellular structure
(b) Total parasite
(c) Undergo crystalization (d) Undergo reproduction
iii)
Bacilli bacteria are
(a) Rounded
(b) Rod shaped
(c) Spiral shaped
(d) Curved
iv)
Streptococci are the bacteria which occur
(a) Two in number
(b) Four in number
(c) In chain
(d) In bunch
v)
Nostoc belongs to
(a) Cocci bacteria
(b) Eubacteria
(c) Cyanobacteria
(d) None of them
Write detailed answers of the following questions:
i)
Discuss in detail the discovery, characteristics, structure and
types of viruses
...
Write short answers of the following questions:
i)
What are the four types of bacteria according to shapes?
ii)
What do you mean by Industrial bacteria?
iii)
Name the five Kingdoms proposed by Whittaker
...
v)
Describe salient features of Cyanobacteria
...
mynoteslibrary
...
Chapter 5
FUNGI AND ALGAE
Algae play an important role in nature
...
Without the oxygen produced by algae,
most of the plants and animals could not survive
...
Fungi, together with bacteria, are at work everywhere on the
earth doing this recycling business
...
• General characters of fungi with reference to Rhizopus, Penicillium,
Agaricus, Ustilago
...
• General characters of algae with reference to Chlamydomonas and Spirogyra
...
5
...
5
...
1 General characters:
According to old concept, fungi were considered as plants and placed in
thallophyta but now they have been assigned a separate kingdom the Fungi
...
ii)
Cell-wall is made up of fungal cellulose
...
iv)
Fungal body is called mycelium which is made up of thread like cells called
hyphae (Sing = Hypha)
...
vi)
They reproduce asexually by means of spores or by budding or
by fragmentation
...
viii)
The mode of nutrition may be saprophytic, parasitic or symbiotic
...
Either they have evolved
from an Alga or from certain unflagellate protozoa
...
Common examples include Yeast, Agaricus,
Penicillium, Rhizopus etc
...
An effort is being made to increase the
cultivation of additional species of mushrooms, especially in Asia
...
Many have a high protein content, as well as a delicate
flavour
...
Some species of penicillium are sources of the well-known antibiotic penicillin
...
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...
5
...
3 Importance of Fungi:
Food: A number of edible fungi in the form of mushrooms are a source of
nourishing and delicious food-dishes
...
But one must bear in mind that not all the
mushrooms are edible
...
Yeasts, another kind of fungi, are utilized in baking industry
...
Medicines: Fungi have opened a new field in medicine being the course of
antibiotics like Penicillin, Chloromycetin, Neomycin, Terramycin etc
...
Fermentation: The property of fermentation is utilized for the manufacture of
ethanol, organic acids and alcoholic beverages
...
Food spoilage: Fungi cause tremendous amounts of spoilage of food-stuff by
many of the saprophytic fungi
...
Plant diseases: Fungi destroy many agricultural crops, fruits, ornamentals and
other kinds of plants
...
Rusts and smuts can cause crop
destruction in large area
...
5
...
Previously algae were regarded as
plants and placed in thallophyta
...
H
...
Finally all the algae have
been placed in Kingdom Protoctista (Margulis and Schwartz)
...
All algae contain green
chlorophyll, but they may also contain other pigments that mask the colour of the
chlorophyll
...
Common examples of Algae are Chlamydomonas, Spirogyra, Ulva etc
...
Chlamydomonas:
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...
It is found growing in still water of ponds, pools, ditches,
tanks, lakes etc
...
It is unicellular, eukaryotic green, motile alga
...
It has cell-wall, cytoplasm, distinct nucleus and two
flagella
...
It is made up of cellulose and pectin
compounds
...
Cytoplasm
has granular endoplasmic reticulum, free ribosomes, mitochondria, golgi bodies,
chloroplast, pyrenoid, contractile vacuoles and an eye-spot
...
It lies towards
posterior end
...
It is a
tiny starch manufacturing factory
...
They are pulsating
in nature under-going alternate expansipn and contraction
...
They may be regarded as excretory
organelles
...
It is situated anterolaterally
...
Flagella are the two cytoplasmic
elongation arising near the contractile vacuoles
...
2
...
Spirogyra is unicellular, but grows in colonial form known as filament
...
All the cells are alike and there is no differentiation of base and apex
in a filament
...
Its outer wall is made up of cellulose
and pectin substances
...
The chloroplast is ribbon shaped with toothed margin
...
These chloroplast
are spirally arranged in protoplasm Each chloroplast has several rounded bodies
along its length, these bodies are made up of protein and are known as
pyrenoids
...
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...
The fungi are distinguished primarily by their sexual reproductive
structures
...
Rusts and smuts are important fungal plant pathogens
...
Some species of Penicillium are sources of the well-known
antibiotic penicillin, and other species of the genus give the characteristic
flavours and aromas to cheese
...
Spirogyra is unicellular, but grows in colonial form known as filament
...
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Biology
Sindh Text Book Board, Jamshoro
...
Fill in the blanks with appropriate terms:
i)
The body of a fungus is called ________
...
iii)
Yeast belongs to _________group of living organism
...
v)
Rust and smuts of cereal crop is due to _______
...
Write whether the following statements are true or false:
i)
Spirogyra is unicellular and colonial
...
iii)
Sargassum belongs to fungi
...
v)
Some species of penicillium are source of antibiotic penicillin
...
i)
ii)
iii)
iv)
v)
Encircle the appropriate answer:
The characteristic not associated with Fungi
(a) Non-chlorophyllous
(b) Coenocytic
(c) Body called mycelium
(d) True cellulose
Which is not a fungus?
(a) Aspergillus
(b) Chlamydomonas
(c) Agaricus
(d) Saccharomyces
Which one is not an alga?
(a)Chlorella (b)Volvox
(c) Spirogyra (d) Yeast
Chloroplast of spirogyra is
(a)Ring shaped
(b)Cup shaped
(c)Ribbon shaped
(d) Spherical
Agaricus is commonly known as
(a) Bread mold
(b) Yeast
(c) Mushroom (d) All of them
4
...
ii)
Describe the structure of Spirogyra and Chlamydomonas?
iii)
Give economic important of fungi
...
v)
Discuss the importance of algae and fungi
...
Define the following terms:
i) Pyrenoid ii) Fungi iii)
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Isogamy iv) Mycellium v)Hyphae
57
Biology
Sindh Text Book Board, Jamshoro
...
They are all
autotroph and manufacture food for all forms of life hence called producers
...
Learning objects:
General characters of Kingdom Plantae
...
General account of Bryophytes with reference to Funaria
...
Study of pteridophyte with reference to Pteris, Adiantum
...
Gymnosperms and study of pinus and Thuja
...
Morphological differences between dicots and monocots
...
1
BRYOPHYTES (Bryon = a moss; phyton = plant)
Bryophytes and tracheophytes are included in Kingdom Plantae
...
Bryophytes are defined as multicellular, eukaryotic, chlorophyllous, non-vascular
plants having cell-wall made up of cellulose and their zygotes develop into an
embryo
...
AH
plants protect their embryos from dessication
...
1
...
They are relatively poorly adapted to
life on land, so are mainly confined to damp shady places
...
They have thalloid bodies which are not
differentiated into true root, stem and leaves
...
Some bryophytes have pseudo
stem and leaves
...
All plants have a life cycle that shows an alternation of generations; some have a
dominant gametophyte and some have a dominant sporophyte
...
It means the
two generations called gametophyte and sporophyte are morphologically as
well as cytologically different
...
The gametophyte reproduces sexually by
producing dissimilar male and female gametes
...
This gives rise to sporophyte, which
may be partly or completely dependent on gametophyte
...
Each spore germinates into a gametophyte
...
1
...
Musci (Mosses)
3
...
mynoteslibrary
...
g
...
e
...
Funaria having rhizoids,stem and leaves
...
g
...
58
Biology
Sindh Text Book Board, Jamshoro
...
The stem may be
branched
...
Fertilization takes place when plant is submerged in water
...
Embryo develops into a
sporophyte, which remains attached with gametophyte
...
The foot is anchored to the gametophyte and absorbs
nutrients from it
...
Within capsule spores are
formed after meiosis
...
Each spore germinates into Funaria gametophyte
...
2
TRACHBOPHYTES (VASCULAR PLANTS)
6
...
1 General characters:
Tracheophyte (Trachea = Vessel; Phyton = Plant) have conducting or vascular
tissues
...
Nearly, all tracheophytes have well developed true root, stem and leaves
...
All tracheophytes show alternation of generation in which sporophyte
generation is dominant and totally independent, whereas gametophyte generation
may be very small, inconspicuous, short lived and totally dependent on
sporophyte except in pteridophytes
...
6
...
2 Major groups of tracheophytes:
Tracheophytes are divided into pteridophytes and spermatophytes
...
They are further divided into psilopsida, lycopsida,
sphenopsida and pteropsida
...
They
are found growing in nature or in moist cool, shady places
...
In the non seed vascular plants, such as ferns, there is a dominant
vascular sporophyte, which produces wind-blown spores
...
i) Pteris:
It is found in wild state in some regions of Punjab but in Sindh it is a common
ornamental plant
...
ii) Adiantum:
It grows in the wild
...
The main plant is sporophyte, a small herb which consists of a stem, roots and
leaves
...
mynoteslibrary
...
Stem — short, thick, rhizome
...
Leaves— large and pinnately compound, having rachis bearing leaflets or pinnae
arranged in an alternate manner
...
Sori— on the under surface of the margin of fertile pinnules occur the sori
...
Spores after liberation from sporangium develop into small gametophyte called
prothallus
...
3 SPERMATOPHYTES — The seed producing plants:
Spermatophytes (Sperma = Seed, Phyton = Plant)are seeds producing plants,
which are divided into two major groups, gymnosperms and angiosperms
...
This gives rise to
naked or covered seeds
...
6
...
1 Gymnosperms: (Gymnos = Nakecf; Sperma = Seed)
Gymnosperms have naked ovules produced in cones
...
We will study Pinus as the
representative of gymnosperms
...
The four divisions of these plants are probably not closely related
...
The height may be 40 to 50 meters and
thickness may be up to 2 meters
...
A conifer is the most typical example of a gymnosperm
...
Following fertilization,! the
seed develops from the ovule, a structure that has been protected within the
body of the sporophyte plant
...
Roots: It has well-developed tap roots
...
Stem: The main stem has two types of branches called long-shoots and dwarf
shoots
...
Foliage leaves are popularly called needles because of their shape
...
They perform the function
of photosynthesis
...
They are present on main stem as
well as on both types of branches
...
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...
They are very
small and never longer than 2cm;Each male cone has a central axis called
thalamus or torus
...
Each microsporophyll has sac like microsporangium which
produce small spores called microspores
...
Female cones: They develop singly in place of dwarf-shoots
...
Each female cone
has an elongated axis (thalamus) on which large number of paired scales are
present called megasporophyll having megasporangium or ovule, each ovule
produce 4 comparatively large megaspores, out of these four, one will survive
and develop into female gametophyte
...
During next season, microspore germinates to form reduced
male-gametophyte
...
Female gametophyte: Each functional megaspore develops into a body called
female gametophyte within megasporangium
...
Fertilization and formation of seed: One of the male gamete fuses with the
ovum to form oospore, becomes diploid
...
In the mean
time, the whole megasporangium develops into seed
...
The two ends of the axis have plumule and radicle
...
THUJA:
In Thuja, the female cones are small, spherical or oval in shape and about the
size of a spherical fruit locally called "bair" (berry)
...
6
...
Angiospcrms
are those flowering tracheophvtes which produce seeds within fruits
...
Angiospcrms are divided into two major groups monocotyledons and dicotyledons
having one and two cotyledons (seed leaves), respectively
...
4
...
Vegetative parts have root, stem and leaves
...
These vegetative parts and
reproductive parts of angiosperm have already been discussed in chapter 2 with
reference to Brassica campestris
...
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...
5 MORPHOLOGICAL DIFFERENCES BETWEEN DICOT AND MONOCOT
PLANTS
Dicot plant
*Plants produce two cotyledon (seed
leaves) containing seed
...
*Stem is mostly branched
...
6
...
*Roots are mostly adventitious
...
*Leaves are comparatively large with
parallel venation
...
Many vascular plants specially angiosperms are source of food e
...
wheat, rice, maize, pulses etc
...
Many vegetables come from vascular plants e
...
potato, cauliflower,
radish, carrots, bean, lady finger, tomato, onion etc
...
Many ingredients of our food also come from vascular plants e
...
mustard,
sugar, coconut, etc
...
Many plants used as fodder belong to this group e
...
grasses, sorghum,
burseem, jantar etc
...
Many delicious fruits come from vascular plants e
...
Apple, mango,
apricot, banana, citrus etc
...
Timber is obtained from these plants, e
...
pinus, deodar, cedrus,
sheesham, kikkar etc
...
Many useful things are obtained from these plant, which serve as medicine
e
...
Amaltas, cinchon, Ajwain etc
...
Fibre of some plants are used in making cloth and rope such as cotton and
jute
...
Many plants are used for beautification as ornamental plant e
...
Rose,
jasmine, shoe flower, glory of night etc
...
mynoteslibrary
...
SUMMARY
Plants may be defined as multicellular, eukaryotic, chlorophyllous living
organisms having cell-wall made up of cellulose and their zygotes develop into
an embryo
...
They are relatively poorly
adapted to life on land, so are mainly confined to damp shady places
...
Bryophytes
show distinct heteromorphic alternation of generation
...
In contrast to other
plants, bryophytes have dominant gametophyte (Haploid)
...
Nearly, all tracheophytes have well developed root, stem and leaves
...
They are found
growing in moist cool, shady places
...
Spermatophytes produce seeds
...
Gyrnnosperms have naked
ovules because cones are without ovaries
...
The body of an angiospermic plant may be divided into two parts, namely
vegetative and reproductive parts
...
Flower is a highly modified form of a branch, which is responsible for the
reproduction of plants by producing seeds within fruits
...
mynoteslibrary
...
2
...
EXERCISE
Fill in the blanks with appropriate terms:
i) Bryophytes are one of the two groups of plants, the other
being________
...
iii) Sporophytic generation is partly or completely dependent on
gametophyte in ______________ plants
...
v) Gymnosperms have ________ ovules
...
ii)
Water is necessary for fertilization in Marchantia
...
iv)
Dryopteris plant belongs to Musci of Bryophyta
...
3
...
Write detailed answers of the following questions:
i)
What are plants?
Give general characters and groups of
bryophytes and tracheophytes with examples
...
Describe any gymnosperm that you have studied
...
iv)
Describe the characters and groups of tracheophyta
...
Define the following terms:
i)
Bryophytes
ii) Plants
iii)
Tracheophytes
iv) Gyrnnosperms
v)
Angiosperms
vi) Spermatophyte
6
...
ii) Bryophyta and tracheophyta
...
and archegonia
...
v) Male and female cone
...
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64
Biology
Sindh Text Book Board, Jamshoro
...
Multicellular
animals called metazoa are divided into two groups those that have backbones
are called vertebrates; those that do not have backbones are called invertebrates
...
They
have many diverse forms and ways of life
...
*
Diversity among invertebrates
...
*
Identification of invertebrates around you and their placement in proper
groups
...
1
Invertebrata: Animals without back bone,
Chordata/Vertebrata:
Animals
having
supporting, rod like structure) in their body
...
They are greater in number, but usually smaller in size than vertebrates
...
Some of the important
phyla are described below:
1
...
They occur either as freeliving (e
...
Amoeba, Paramecium, Euglena, etc
...
Common
protozoan parasites are Plasmodium and Entamoeba histolytica which cause,
important human diseases malaria and dysentery, respectively
...
Paramecium lives in fresh water pond
...
Paramecium has
two nuclei, one is larger called macronucleus while the other one is smaller
called micronucleus
...
According to the recent classification protozoa is not included in kingdom animalia
but has been placed in kingdom Protoctista (Protista)
...
Phylum Porifera:
Porifera are the simplest group of multi-cellular (many celled) animals
...
The entire
body has numerous minute pores or ostia
...
All sponges are aquatic (live in water) and sessile (fixed at one place
throughout their life)
...
The water then
leaves the body of sponge through another opening, the osculum
...
mynoteslibrary
...
Sponges have an internal skeleton of hard structures called spicules, which are
formed of calcium carbonate or silica
...
Common examples of sponge are Sycon,
Venus flower basket and bath sponge
...
It is a colonial form which is found in shallow water in being attached
by a sticky secretion to some submerged solid object like rocks, shells of molluscs
and corals
...
The free end of each opening, the osculum
...
Phylum Cnidaria (Coelenterata):
Coelenterates are aquatic animals
...
Cells of coelenterates are organized to form tissues
...
In between these two layers are a jelly like,
non-living layer called mesoglea
...
g
...
They occur as free
living animals, cither living singly e
...
Hydra or in the form of a colony e
...
Obelia
...
Its body is cylindrical with several thread-like tentacles at its one end encircling
an opening called mouth
...
The tentacles
are used for capturing the prey
...
The prey is digested in the coelenteron
...
Jelly fishes live in the sea
...
They swim freely in water
...
It is encircled by four long arms each bearing numerous stinging
cells
...
4
...
They
occur mostly as parasites of animals as well as man
...
Platyhelminthes are
triploblastic animals because of the development of a middle layer of cells, the
mesoderm, in between ectoderm and endoderm
...
It is a parasite in
the liver of sheep, goat and cattle
...
It has a bifurcated, highly branched
digestive system
...
Each liver fluke has both male and
female reproductive organs
...
Tape worms live in the intestine of their vertebrate hosts
...
The anterior end is some what
rounded and head like
...
Tape worm lacks digestive system,
mouth and anus
...
Every segment has a set of male and a female reproductive organs
...
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...
5
...
The body is unsegmented
...
They are free-living as well as parasites of animals, man and even plants
...
It lives in the intestine of man
...
6
...
The segmentation in
annelids is both external as well as internal
...
Annelids occur in water as well as on land
...
g
...
while few are ectoparasites e
...
leech,
etc
...
However,
respiration occurs through their general body surface
...
e blood circulates
in blood vessels being pumped by
...
The leech lives in ponds
...
It sucks the blood of its host
...
Phylum Arthropoda:
Phylum Arthropoda is the largest phylum of Kingdom Animalia
...
Their body is covered externally with a hard covering called
exo-skeleton which is made up of a complex chemical called chitin
...
The body of an arthropod is usually divisible
into three distinct regions; an anterior head, a middle thorax and a posterior
abdomen
...
Insects are the most abundant animals on earth
...
Many of them
have wings to fly
...
Many insects such as mosquitoes hatch out of their eggs in a premature form and
pass through different stages of development to reach the adult stage
...
Metamorphosis is of two types:
i)
Complete metamorphosis
ii)
Incomplete metamorphosis
i)
Complete metamorphosis:
In complete metamorphosis, the young one, the larva, which hatches out of egg
is morphologically completely different from adult
...
After going through farther changes,
the pupa comes out of its capsule, it is now termed adult
...
Insects such as butter flies, mosquitoes, house flies, etc
...
ii)
Incomplete metamorphosis:
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Biology
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After the development of wings and
maturity of reproductive organs, the nymph becomes adult
...
Common insects are house-fly, butter-fly, mosquito, cockroach, honey-bee,
termite, etc
...
Phylum Mollusca:
Animals of this group have a soft, fleshy body enclosed in a thin fleshy cover
called mantle
...
They mostly occur in water but some are
found on land
...
It helps in locomotion
...
Common examples of molluscs
are snail, pearl oyster, squid, octopus, and fresh water mussel
...
Snails have spirally coiled shells and are commonly seen in lawns and gardens
...
9
...
They are found only in the sea
...
This vascular system operates the soft,
tube shaped feet (tube feet) which enable the animal to glide over the rocks in
water
...
Common examples of phylum
echinodermata are star-fish-, sand-dollar, sea-cucumber, sea urchins etc
...
Sea Urchin has a ball-like body without arms
...
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Invertebrates are divided into a number of smaller groups or phyla
...
Protozoa are unicellular animal like organisms which are now placed in
kingdom Protoctista (Protista)
...
Coclentcrates are multicellular and diploblastic
...
Nematodes have elongated, un-segmented body pointed at both the ends
...
Arthropoda is the largest phylum
...
Around 95% of
the arthropods are insects
...
Molluscs have soft fleshy body enclosed in a soft membranous cover called
mantle which may be covered over by a hard shell
...
mynoteslibrary
...
EXERCISE
1
...
Write whether the following statements are true or false:
i)
ii)
iii)
iv)
3
...
(a) Porifera (b) Arthropoda
(c) Nematoda
(d) Protozoa
...
(a) Protozoa (b) Annelida
(c) Echinodermata
(d) Mollusca
...
Write detailed answers to the following questions:
i)
ii)
iv)
iv)
5
...
Nematodes are segmented worms
...
Water vascular system is a feature of sponges
...
The external, protective covering which develops in arthropods
is called __________
...
Animals fixed at one place are called ________
...
House flics, mosquitoes, butterflies belong to class ________
...
Echinodermates have ________ skin
...
Discuss important characters of Phylum Arthropoda
...
Discuss important features of diploblastic animals
...
How do they get food while staying at one
place?
You have studied different groups of animals
...
What do you know about insects?
What is exoskeleton? Name two phyla of animals having
exoskeleton
...
Name five parasites and the phyla to which
they belong
...
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Biology
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...
All
vertebrates have a spinal column made up of bones called vertebrae
...
This cord is joined to highly developed brain
...
This superior nervous system is the real key to
the biological supremacy of vertebrates
...
*
Vertebrates relation with chordates
...
*
Important features of vertebrate groups
...
which you commonly observe
around you belong to the phylum Chordata
...
Although, chordates are less numerous in number than invertebrates, yet
they occur in greater diversity
...
It
is one of the basic features present in all chordates
...
Notochord,
hollow dorsal nerve cord and pharyngeal gill slits are considered as the basic
features of all chordates
...
Later in adult life, they may be modified
or even lost
...
1
VERTEBRATA
Most of the chordates belong to the group vertebrata
...
Their brain is also
protected in a brain box
...
1) Pisces (Fishes)
2) Amphibia
3) Reptilia
4) Aves (Birds)
5) Mammalia
1
...
The body of fish is
stream-lined (spindle shaped) to offer less resistance to water while swimming
...
Their body can be differentiated into head, trunk
and tail
...
They bear paired fins rather
than legs which help them in swimming
...
They are not used for grinding the food
...
e
...
Common examples of this group are sharks, Labeo (RohuArout,
Hilsa (Pullah), and Catfish (Khagga)
...
Its gills are covered
with bony plates or opercula (Sing, operculum) and the skin has external
skeleton of large scales
...
mynoteslibrary
...
Fishes, the largest group of vertebrates, are very important source of food for
animals as well as for man
...
Fishing is also a popular sport throughout the world
...
Class Amphibia:
They live in water during their early life
...
For this reason they are termed as Amphibia (means dual life)
...
Breathing in early stages occurs through gills
...
Adult amphibia have a naked skin which is thin, moist and slimy skin,
which is also used for exchange of gases (oxygen and carbon dioxide)
...
Common examples of amphibia are frogs, toads,
and salamanders
...
Some frogs live on trees
...
Largest frog found in Africa is about 30 cms in length
...
It lives close to water
...
Toads usually have dull
coloured skin with less jumping capability
...
The immature young one which hatches out of
egg is called tadpole larva
...
During winter, in order to avoid low temperature, frogs
burry themselves in the mud present at the bottom of pond
...
3
...
Unlike amphibia, they lay their large shelled eggs on land rather than in water
...
They breathe by lungs
...
However, some are also aquatic
...
Both the jaws in reptiles bear teeth
...
Very early reptiles called dinosaurs were huge animals but they do not live now
...
House (Wall) lizard is familiar to you
...
It crawls on walls or
even on ceilings because of special kind of adhesive pads on their fingers
...
Some of them (e
...
Cobra) are well known for
their deadly poison
...
Poison is injected into the prey through special, long pointed
teeth called fangs which can regenerate if broken
...
In fact, most snakes are non-poisonous
...
Class Aves (Birds):
This class includes all the birds
...
Most of the birds can fly with the help of their wings and feathers
...
Although birds live on
land, some birds are also aquatic and can live in water
...
mynoteslibrary
...
of their neck
...
Eggs are laid on land
...
Parrot, sparrow, pigeon, ostrich, kiwi are some of the common
examples of birds
...
it feeds on the nectar of flower
...
Its egg is about 1 to 2 lbs in weight
Pigeons were used to serve as a means of dispatching letters in the old times
...
Pigeons are among the
modern birds which can fly for hours in the skies
...
Their wings are short and feathers are hair-like
...
5
...
Mammary glands are functional and secrete milk in females, which is used
to feed their young ones
...
In
addition to mammary glands, skin also contains sweat glands, sebaceous
glands and scent glands
...
Like birds, they are also warm blooded animals
...
Mammals can be divided into three subgroups
...
Like reptiles, they lay eggs
...
Since they have characters of both reptiles and mammals, they are
considered to be connecting link between reptiles and mammals
...
Both
are found only in Australia
...
As the new born babies are weak, the
mother keeps them in a pouch on its belly until they develop fully and become
strong enough for independent life
...
Kangaroo, koala bear and
opossum are common examples of pouched mammals
...
In placental mammals,
the young one completes its development inside the body of its mother where it
is fed through on organ called placenta
...
Common examples of placental mammals are man monkey, elephant, rat, cat,
lion, bat, seal, whale and dolphin
...
mynoteslibrary
...
Although mammals are chiefly terrestrial, some (e
...
whale dolphin seal, etc) live
in water
...
Bats are unique
as they can fly
...
2
LOCAL FLORA AND FAUNA OF PAKISTAN
Pakistan has a long stretch of high mountains in its north and north-west,
plateaus in Baluchistan and Potohar, plains of Indus and patches of deserts in
Punjab and Sindh
...
Thus when we speak of flora, we mean
plant life and when we speak of fauna, we mean animal life
...
It is
our duty to take care of these valuable gifts of nature
...
Flora:
Our country has representatives of all groups of plants which you have studied
...
Forests and forestry are considered to be the backbone of our
economy
...
They prevent formation of
deserts, control water logging and maintain the amount of salts in the soil and
regulate the temperature of atmosphere
...
They are an integral part
of our ecosystem
...
These forests consist of trees like blue
pine, chir pine, chalghoza pine, deodar, fir, juniper and olives, etc
...
Trees of Sheesham, Mulberry, Willow, Poplar, Neem
etc
...
These forests play a key role
in providing us wood for furniture, sports goods and fuel
...
These crops include wheat, maize, rice, sugar cane, sugar beet,
pea, potato, tomato, onion, garlic, chili, turnip, radish carrot, cauliflower, many
cereals, grains and cotton, etc
...
Many plants are cultivated for
ornamental purpose e
...
Chrysanthemum, roses and jasmines etc
...
Still a large number of plants like Typha, Hydrilla, and many
types of algae are found in fresh water ponds, lakes, streams and river
...
The above mentioned plants not only provide us food but are also important for
their medicinal values
...
Is it not a good idea to
prepare a list of plants found in your locality? It will increase your knowledge of
the flora of Pakistan
...
mynoteslibrary
...
2
...
Each
one of these groups holds an important position in its biological relationship with
plants and with human beings
...
There are, however, a few facts which you should
remember
...
These are considered to be one of the best fishing grounds in the world
...
Fishes in large number and
variety are found in our sea
...
Fishes in general are of great commercial value
...
You are undoubtedly familiar with our common amphibians, frogs and toads
...
Cobra, krait, vipers and pythons are
among our common snakes
...
Every year large number of migratory
water birds like ducks visit our lakes
...
Other common birds are Houbara bustard, crane, water fowl, falcon, eagle, kite,
peacock, pigeon, crow, parrots etc
...
We have a variety of deer
...
Uncontrolled hunting has endangered their survival
...
Our monkey is endangered because of its great demand in overseas
markets
...
They provide us milk and meat
...
Pakistan has large variety of
these animals
...
Cows, buffaloes, donkeys, horses! goats and camels are the
common domesticated forms
...
are much
endangered animals of Pakistan
...
Fauna
and flora are biologically inseparable because of their interrelationship and have
an impact on our own welfare or even survival
...
If this balance is disturbed, each
one would be negatively affected
...
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Biology
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...
, in vertebrates notochord is
replaced by vertebral column
...
Pisces, amphibia and reptiliaare cold blooded animals
...
Pisces have paired as well as unpaired fins on their bodies
...
Snakes are limb-less reptiles
...
Most mammals give birth to young ones
...
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76
Biology
1
...
EXERCISE
Fill in the blanks with appropriate terms:
i)
The name chordata refers to the presence of a solid, elastic rod
like, supporting structure called the___________
...
iii)
The skin of fish is usually covered over with ________
...
v)
Birds and mammals are _________ blooded animals
...
Write whether the following statements are true or false:
i)
Adult frogs are gill breathers
...
iii)
Birds have hair on their skin
...
Encircle the appropriate answer:
i)
It is not cold blooded
...
(a) Kiwi
(b)Deer
(c) Tiger
(d) Dinosaur
iv)
It gives birth to young one
...
(a) Shark
(b)Frog
(c) Elephant
(d) Sparrow
4
...
Give examples
...
iii)
What is Pisces? Discuss their important characters
...
v)
Discuss general characters of the vertebrates with naked skin
...
Write short answers of the following questions:
(i)
Make a list of basic characters of chordates
...
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...
It is
like a factory, a place of great activity, where fuel and raw materials are taken
and converted into finished products and energy
...
Energy keeps this machine system working and up till these major
systems are working, in co-ordination, organism is alive whenever they stop, life
ceases to survive
...
Nutrients are chemical substances needed by the body
...
They repair the older body cells and form new ones
...
Importance of food to obtain nutrients
...
Autotrophic nutrition in plants
...
Special modes of nutrition in plants
...
Nutrition in human beings and components of their food
...
Disorders of the gut
...
To meet these
demands they intake two main categories of molecules from environment:
already synthesized high-energy compounds (food) or the raw materials from
which new protoplasm can be synthesized
...
Materials required for the synthesis of new
protoplasm as well as for the production of energy are called nutrients
...
1 NEED FOR FOOD
All living organisms need food
...
They also need food as a source of energy
...
In living organisms food drives essential living processes and brings about
chemical changes
...
It also provides materials to maintain various processes of life such as
reproduction, respiration etc
...
(i)
Autotrophic organisms
(ii)
Heterotrophic organisms
(i) Autotrophic organisms: Organisms, which can synthesize their own organic
compounds (food) from inorganic raw material taken from inorganic
surroundings
...
Most of the autotrophs are photo synthetic e
...
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Biology
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...
They obtain
synthesized food from their environment
...
e broken down into smaller, more easily absorbable
molecular units
...
1
...
Proteins
3
...
Vitamins
5
...
Water
9
...
Most of them are large and complex
...
Small molecules (e
...
Glucose) arc used as sub-units to
synthesize longer molecules e
...
starch
...
All polymers are synthesized by a process called
condensation
...
Monomers
Monosaccharides e
...
glucose
Amino acids
Fatty acid and Glycerol
Polymer
Polysaccharide e
...
starch and
glycogen
Proteins
Fats and oils
Simple Sugar to Starch and Glycogen:
Starch, glycogen and simple sugar (glucose, fructose etc), belong to a group of
organic compounds called carbohydrates
...
The most common simple sugar is grape sugar called
glucose (C6 H12 O6)
...
Fig: 9
...
g
...
When
many simple sugar molecules join in long chain, they form the most complex
polysaccharide carbohydrates such as cellulose, glycogen and starch
...
9
...
2 Amino acid to proteins:
Amino acids are the monomers that condense to form proteins, which are very
large molecules
...
There are 20 kinds of amino acids which combine in different kinds of proteins
...
2 Formation of a simple Protein molecule by the combination of amino
acids
As you know that the English language has 26 letters of the alphabet and they
form millions of different words
...
mynoteslibrary
...
great variety of proteins
...
Main role of protein is to provide building material in the body
...
They make structures like muscles,
nails and hairs
...
2
...
A fat or oil is a molecule
which is formed by the condensation of 3 molecules of fatty acid with a glycerol
by removing 3 molecules of water
...
Examples of oils are cotton seed oil corn oil coconut oil, soyabean oil
...
Organisms use fat molecules as long term energy storage compounds
...
3 Diagram showing how fats are formed from glycerol and fatty acids
9
...
Plants, on the other
hand, first make the food they need and then use it for energy and growth
...
Some are
heterotrophic and live as parasites or saprophytes
...
In dealing with life processes in plants in this chapter, we shall first discuss
photosynthesis and its processes
...
3
...
In this
process a plant can build sugar by taking carbon dioxide from air and water from
the soil
...
The plant builds sugar
molecules from these simple compounds
...
The
process if completed in the mesophyll cells of the leaves as shown in Fig: 9
...
The reaction is expressed by the following chemical equations:
6CO2
+
Light Energy
6H2O
Carbon dioxide
Chlorophyll
+
Water
(Raw material)
C6H12O6
+
Glucose
6O2
+ Oxygen
(Product)
This equation shows only the starting materials and end products of the process
but gives no information about the intermediate reaction steps involved
...
During day
light, green plants take in carbon dioxide and give out oxygen
...
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Biology
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...
4 Photosynthesis in plants
9
...
2 Morphology and Anatomy of leaf related with Photosynthesis:
In plants, leaves are the most appropriate structures which are adapted fog
photosynthesis
...
The
following characters explain their adaptability towards photosynthesis
...
Their broad flat shape offers a large surface area for absorption of
sunlight and carbon dioxide
...
Most leaves are thin and the CO2 has to diffuse across only short
distances to reach the inner cells
...
The large spaces between cells inside the leaf provide an easy passage
through which C02 can diffuse
...
There are many stomata (pores) mostly in the lower surface of the leaf
which allow the exchange of CO2 and O2 with the air outside
...
There are more chloroplasts in the upper cells than in the lower cell
because the cells of upper surface receive more sunlight
...
The branching network of veins and veinlets provide a good water
supply to the photosynthesizing cells and no cell is very far from a
water conducting vessel
...
5 (a) The external appearance of leaf shows the transport tissues
...
5 (b) Transverse section through part of a leaf
...
The upper and lower
surfaces of a leaf consist of a layer of transparent cells, the epidermis
...
Inside the leaf,
there are a few layers of cells collectively called mesophyll (which means simply
middle of leaf) where photosynthesis occurs predominantly
...
3
...
The external factors are sunlight, water, carbon dioxide and temperature
...
It is present in special structure within a cell
called chloroplast
...
1
...
However, they will not combine in the absence of sunlight because
various reaction steps necessary for synthesis of glucose require energy input
...
As light is composed of seven colours; rays of
two colours chiefly red and blue, are used in the process
...
Very intense light is harmful, while light of
moderate intensity accelerates and weak light slows down the rate of
photosynthesis
...
Photosynthesis can also take place in artificial light
...
Chlorophyll:
Chlorophyll imparts green colour to the leaves
...
Photosynthesis will not proceed without
chlorophyll and that is why it occurs only in the parts of the leaf or stem that
contain chlorophyll
...
mynoteslibrary
...
3
...
It
enters the leaf through the stomata
...
Photosynthesis will not take place without carbon dioxide
...
03 to 0
...
The process of photosynthesis accelerates if its proportion is
increased up to 1
...
However, greater amounts of carbon dioxide, adversely
affect the process
...
Water:
This constituent is as basic as is carbon dioxide
...
It is important that stomata should remain open
so that carbon dioxide may enter leaves
...
g
...
5
...
Normally a
temperature range of 15°C to 30°C is most suitable for this process
...
However, depending on regions, the temperature requirements of the
plants may change
...
9
...
4 Conversion of light energy into chemical energy:
Photosynthesis is the metabolic process by which plants trap light energy, convert
it into chemical energy and store it in the bonds of organic nutrient molecules
such as glucose and release O2 as by-product
...
These reactions occur at different sites in the chloroplast
...
1
...
Dark reaction
1
...
Some of the light is utilized to split water into oxygen and hydrogen
...
Oxygen which is
produced during photolysis is released in the environment whereas hydrogen
together which CO2 is used in building glucose
...
The conversion of light energy into
chemical energy in these photosystems produces two energy rich compounds
...
mynoteslibrary
...
NADP, which already exists in the chloroplast reduces into NADPH2 by accepting
hydrogen ion released from splitting of water
...
Light energy
ADP + P
ATP
Enzyme
Reduction and oxidation are two important chemical concepts which help us to
understand the terminology of the electron transfer chain
...
In biological systems this
addition of electrons is usually brought about by the addition of hydrogen or the
removal of O2
...
ATP and NADPH2, both are energy rich compounds
...
Fig: 9
...
Dark reaction:
Dark reaction is also called light independent reaction because light energy is not
captured during this phase
...
Fixation of CO2 and its conversion into glucose occurs in the chloroplast by means
of a series of reactions known as Calvin cycle or dark reactions
...
Melvin Calvin a scientist received a Nobel prize in 1961 on determining the dark reaction
...
1
Is chlorophyll necessary for Photosynthesis ?
Since it is not possible to remove chlorophyll from a leaf without killing it, so it
becomes necessary to use a leaf where chlorophyll is present only in patches
...
For destarching the leaves, the potted plant is kept in a dark place for a couple of
days and then exposed to daylight for a few hour
...
Its out line is carefully drawn to note the position of presence or absence of
chlorophyll on it
...
(Startch whenever come in contact with iodine turns blue)
...
This result indicates that starch is
formed only in those parts of the leaf where chlorophyll exists (i
...
green parts)
...
If this were
possible the white parts of the leaf should have also given a blue colour with
iodine
...
mynoteslibrary
...
7
Sindh Text Book Board, Jamshoro
...
2
Is light necessary for Photosynthesis?
A potted plant is destarched by keeping it in the dark room for two days
...
Two of its leaves are selected for the examination
...
The other leaf is also wrapped in black
paper but an L-shaped part of the paper is cut out so that light can reach this
part of the leaf through it
...
The
two leaves are now detached from the plant and tested for presence of starch
...
However, in the second leaf, light could pass
through the L-shaped opening in the black paper
...
This shows that light
plays a vital role in the manufacture of starch
...
Fig: 9
...
3
Is carbon dioxide needed for Photosynthesis?
Two potted plants are destarched by keeping them in a dark room
...
Each pot is enclosed in a transparent
polythene bag as shown in figure 9
...
A petri dish containing soda lime (potassium hydroxide) is placed in one of the
pots to absorb any carbon dioxide present in the polythene bag
...
The plants are then left in light for several hours
...
The leaf from the pot containing
soda lime does not turn blue
...
The leaf from the other pot where carbon dioxide was being released
by the sodium bicarbonates solution turns blue indicating the presence of starch
...
Fig: 9
...
4
Is oxygen produced during Photosynthesis?
A short stemmed funnel is placed over the shoot of an aquatic plant (Hydrilla) in
a beaker of water as shown in fig
...
10
...
The funnel is placed in the beaker on supports, to allow
free circulation of water
...
Bubbles
of gas soon appear from the plant, rise and collect in the test tube
...
A glowing match stick is
inserted in the tube
...
It is clear from this experiment that oxygen is evolved during
photosynthesis
...
10 To show that Oxygen is set free during photosynthesis
9
...
5 Factors affecting the rate of photosynthesis:
The rate of photosynthesis is affected by a number of factors
...
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The brighter the light,
the faster will water molecules split in the chloroplast
...
9
...
Beyond that point, any further increase in light intensity has only a small
effect
...
So, no matter how much the light intensity
increases, no more light can be absorbed and used
...
11 Light intensity and rate of photosynthesis
Temperature:
The dark reaction will be affected by temperature
...
Thus rate of photosynthesis increases with the increase in temperature within
optimum limits
...
03% of CO2 in the air
...
Experiments show that an
increase in CO2 concentration enhances the rate of photosynthesis
...
At low concentration of CO2 inside the leaf, the stomata will open
...
3
...
The photosynthesis is the only process which can fix atmospheric CO2 into organic
compounds to produce bio-molecules
...
Thus, they are the direct or indirect source of food for all the nonphotosynthetic life on earth
...
During photosynthesis they fix CO2 and release oxygen
in environment
...
One of the property of CO2 is that it absorbs heat of sun
...
Photosynthesis keep on using CO2 has an indirect cooling effect
...
3
...
These
two compounds provide only three elements, C, H, and O, but plants require
more elements for the composition of their molecules, e
...
Nitrogen (N) is
always present in amino acids, the building- block units of proteins which are
essential components of protoplasm, some amino acid also contain sulphur (S)
...
Chlorophyll, essential pigment of photosynthesis contains
magnesium while cytochrome important compound in electron, transport,
contain iron
...
Table 9
...
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9
...
8 Importance of chemical fertilizers in Agriculture:
Inorganic fertilizers help to replace the mineral ions consumed from the soil by
successive production of crop
...
Modern commercial inorganic fertilizers are often designated by their N-P-K
percentages e
...
the widely used garden fertilizer called 5-10-5 contains 5% N,
10% P and 5% soluble K by weight
...
Phosphorous and potassium are added in the form of super phosphate
and potassium chloride, respectively
...
4
SPECIAL MODES OF NUTRITION
Plants, usually being autotrophic, are directly or indirectly the source of food for
all organisms on this earth
...
Such plants are known as heterotrophic plants
...
1
...
Saprophytes
3
...
Symbionts
...
Parasites:
These are entirely or partially dependent upon autotrophic plants for their food
supply
...
An
important feature of these plants is that they have special roots known as
haustoria which absorb ready made food from the host plant
...
A well known parasitic plants is cuscuta
...
Fig: 9
...
Saprophytes:
These plants have no chlorophyll and derive their food from dead organic matter
...
These plants are found in thick jungles where sunlight cannot reach the
ground and the soil is rich in decomposing organic matter
...
The roots
of these plants develop in association with a special type of fungus
...
These hyphae thus serve
as 'root hairs' and help in the absorption of the food from the dead organic
matter
...
13
Monotropa
...
Insectivores:
These plants are found in marshy areas of many countries
...
To make up for this deficiency
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They
attract insects with their peculiar shape, colour and nectar and then trap them
inside their modified leaves
...
The insectivorous plants can make their food by photosynthesis because of
chlorophyll in their leaves and can survive without eating insects
...
They bear more flowers, fruits and
seeds
...
It is found along Eastern Himalayas
...
It is here that insects are trapped
...
It is green due to the presence of chlorophyll
...
Fig: 9
...
Symbionts:
An association of two organisms in which both the partners get benefits is called
symbiosis
...
Lichens are another example of
symbiosis
...
The fungus provides shelter and water to the alga
...
Fig: 9
...
The alga produces food; the fungus may provide protection and moisture
...
5
NUTRITION IN ANIMALS
Animals cannot manufacture their food from simple inorganic substances so they
have to obtain' organic molecules from then-environment in the form of food
...
As
animals obtain their food from other organisms, this type of nutrition is also
called heterotrophic nutrition
...
Carnivores:
This type of nutrition in which animals feed upon other animals is called
carnivorous nutrition
...
For example cat, dog,
etc
...
2
...
For example, horse, cattle, deer,
etc feed upon leaves and grass
...
They do not
have canines
...
are also herbivores
...
Omnivores:
It is the mode of nutrition in which animals feed upon flesh as well as plants
...
fall into this category
...
4
...
are frugivores
and this type of nutrition is called frugivorous
...
mynoteslibrary
...
5
...
For example wall lizard and frog
feed upon-a-variety of insects
...
6
...
Organisms with this type of nutrition are called parasites
...
Some
parasites live on the external surface of their hosts
...
g
...
They obtain their food from the surface of
the host
...
They are called
endoparasites e
...
tape worms and round worms in the intestine of vertebrates
...
7
...
Saprobes secrete the enzymes out side
their bodies, on the food to digest it and then absorb it in the fluid form
...
9
...
6
...
Moreover, food is needed to make enzymes for various metabolic
processes
...
(1) Carbohydrates
(2) Fats
(3) Proteins
(4) Vitamins
(5) Minerals
(6) Water
1
...
Common examples are starch, sugars, etc
...
It is the most readily available source of energy
...
Fats:
Fats belong to a group of organic compounds called lipids
...
They provide double amount of energy upon oxidation, in contrast to the
same quantity of carbohydrates
...
g
...
g
...
Animals store fats beneath the skin and around some visceral organs
...
They also serve as building material of protoplasm and membrane systems
...
Proteins:
Proteins are the building materials of protoplasm
...
They consist of smaller units called amino
acids
...
, the deficiency of proteins in diet especially that of essential amino acids
containing proteins, severely affects such functions
...
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Minerals:
Minerals are ionic substances which are required in metabolic activities of the
body
...
Some important minerals are described below:
Calcium: It is obtained from milk, eggs, fruits, and cereals
...
It also helps in muscular contraction, blood clotting and
conduction of nerve impulse
...
It is
used in synthesis of haemoglobin and myoglobin in blood and muscles,
respectively
...
It is required for
bones, teeth, formation of plasma membrane, nucleic acids, and ATP
...
Vitamins:
Vitamins are organic compounds which are needed in minute quantities for proper
growth and development of the body
...
There are
different vitamins which are denoted by letters of the alphabets such as A, B, C,
D, E, K
...
g
...
g
...
Fat soluble vitamins can be stored along with, fat but
water soluble vitamins cannot be stored so we require continuous intake of them
...
2 shows different vitamins alongwith their sources, their deficiency
disorders and characterization of disorders
...
2 Vitamins and their functions
Name of
Sources of
Characters
Vitamin
vitamins
of disorder
Vitamin A
Vitamin D
Fat soluble vitamins
Vitamin E
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Fish-liver oil,
animal liver,
milk, cheese,
fresh green
vegetables
...
Also made by
action of
sunlight on
skin
...
Essential for
vision, growth
and
functioning of
skin, etc
...
In
adults bones
become
painful and
can be
fractured
easily
...
Severe
deficiency in
infants may
cause high
rate of
destruction of
Disorders
caused by
lack /
deficiency
Dry cornea,
dry skin poor
night vision
...
Anemia
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Made by
bacteria in
intestine
...
Leafy
vegetables,
fish, eggs
...
Citrus fruits
and green
vegetables
...
Prolong
clotting time
excessive
bleeding
Wasting of
muscles;
circulatory
failure and
paralysis
Sore
mouth,
eyes and skin
Diarrhea,
dermatitis and
mental
disorder
Bleeding from
gums, wounds
fail to heal
Blood does
not clot
Beri Beri
Sore
Pellagra
Scurvy
6
...
It is required as
solvent in most of the metabolic activities of the body
...
It helps plants in
photosynthesis for intake of minerals from the soil and in movement of food
...
7
DIETARY FIBRES (Roughage)
Dietary fibre or roughage is made up of the indigestible cell walls of plant cells
that we take in our food such as fruits, vegetables
...
It also stimulates the gut for peristaltic
movement which makes the passage of food easier through the gut for
defecation
...
9
...
1 Nutrition and food technology:
We eat food in order to obtain energy for the maintenance of life and also to
provide raw materials to build and repair the body
...
Unfortunately, the production of food is seasonal and not uniform
throughout the world
...
Food is destroyed either by the growth of micro-organisms such as bacteria, fungi
or due to the enzymes of the cells of food
...
The nutritional value and taste were considerably
lost in food preserved through such traditional methods
...
Some of the important methods are as follows:
1
...
You all
know very well that milk is boiled after purchasing it from milk- man
...
mynoteslibrary
...
temperature of milk up to the boiling point, kills most of the germs (bacteria)
present in it thus milk can be kept longer
...
The modern way of milk pasteurization comprises of heating to
71 °C and then immediate cooling
...
2
...
In this method food is kept at
very low temperature at -30°C to -40°C
...
Now-a-days, food quickly
freezes (-18°C) in about 30 minutes
...
3
...
Although drying of food
does not kill micro-organisms, it preserves the food as it makes water unavailable
to micro-organisms which requires it to grow and multiply
...
However, it often brings about a
change in texture and taste of the preserved food
...
Canning:
In this method, food is adequately cooked and then sealed while hot in a sterile,
metallic and air tight container
...
HEALTH PROBLEMS RELATED TO NUTRITION
The problems related to nutrition are as follows
...
Under-nutrition
2
...
Over-nutrition
1
...
Famine stricken countries such as Ethiopia are facing this problem
...
Due to insufficient food, their
physical as well as mental growth are severely affected
...
Fig: 9
...
2
...
It can affect person of
any age or group
...
It has
been noticed that mal-nutrition is the major cause of death among the children
upto the age of five in the world especially in developing countries
...
17 Effects of malnutrition (Girls of the same age)
In Africa and Asia, due to poverty and famine, the diet is usually deficient in
proteins and carbohydrates
...
3
...
Obesity
is the most common disorders due to over-nutrition
...
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It helps in proper growth,
metabolism, and maintenance of good health
...
The problem of doing
this is complicated by the fact that the body's food requirements vary
according to age, body size, sex, occupation, and health
...
Youth on the other hand need more
food than elderly people because of their active physical work
...
Fats are necessary in diet as they contain fat soluble vitamins as well as
fatty acids
...
How ever infants should be given 2gm per kg from
birth to six months
...
Raw food (100g)
Rice
Eggs
Butter
Milk (Mother)
Milk (Cow)
Sugar
Beef
Fish
Mutton
Beans
Orange
Apple
Energy (K
...
9 DIGESTION IN MAN
Man, like other animals takes food that consists of complex and larger molecules
...
The bread of
the sandwich contains starch which is insoluble and chemically different from
glycogen or glucose
...
Also the proteins of sandwich are useless to you in the form they are
eaten
...
- This process is called digestion
...
This tube called alimentary canal, opens at the anterior end of the body through
an opening called mouth and at the posterior end through another opening called
anus
...
Alimentary canal is
associated with a number of glands like salivary glands, liver and pancreas which
secrete digestive juices containing special chemicals called enzymes to bring
about the chemical digestion of food
...
The alimentary canal is differentiated into buccal cavity, oesophagus, stomach,
small intestine and large intestine
...
Ingestion
2
...
Absorption
4
...
Egestion
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9
...
In the mouth cavity also called buccal cavity or oral cavity, this food is
cut down into smaller pieces with our teeth
...
The process of breaking the food
mechanically into smaller pieces is called mechanical digestion while the
chemical break down of food into smaller chemical molecules is called chemical
digestion which is brought about by enzymes
...
Teeth:
As stated above, teeth in our oral (mouth) cavity perform mechanical digestion
...
We have two sets of
teeth during life time
...
Later, about at the age of 7 years, the milk teeth gradually fell
and are replaced one by one by permanent teeth
...
(i
...
Structure of tooth:
Each tooth consists of three parts i
...
crown, neck and root
...
It is the biting or
chewing surface of tooth
...
The outer surface of crown is covered by a very hard white substance, the
enamel
...
The root as well as the portion inside the enamel is dentine
...
Inside the dentine, there is a cavity, the pulp cavity
...
It also contains nerves and blood
vessels that supply the growing tooth with food and oxygen
...
The tough fibers of periodontal membrane attach the cement to the jaw bone so
that each tooth is fixed firmly in socket
...
18 Structure of a tooth
Types of teeth:
According to the shape and function following types of teeth are present in our
oral cavity
...
Molar: The molars are large strong teeth efficient at grinding food
...
Incisors: These teeth have a chisel shaped, sharp cutting edge ideal for biting
...
Fig: 9
...
They are eight in number, four in upper while four in the lower jaws
...
ii) Canines: Beside incisors lie canines on each side in both jaws
...
They are used for tearing and pulling flesh
...
mynoteslibrary
...
why they are very long and prominent in carnivores such as lion
...
iii) Premolars: In both jaws each canine is followed by two premolars
...
They are involved in grinding the
food
...
They are 12 in number
...
The last molar is called wisdom
tooth
...
I2/2, C 1/1, Pm 2/2, M 3/3
It represents each type of tooth in half of the upper jaw and half of the lower jaw
...
The causes of tooth decay and its prevention:
Tooth decay refers to erosion of enamel and dentine
...
The plaque develops as a hard layer over teeth due to not brushing or
improper brushing of teeth after each meal
...
The bacteria feed on left over sweet
which is broken down to produce an acid that gradually destroys enamel forming
a cavity in it
...
Bacteria feeding on the sugar form acids, which dissolve the enamel and
dentine and hole starts forming
...
The infection can spread rapidly through the pulp cavity and may form an
abscess at the root of the tooth
...
20 Tooth decay
If this decay is ignored, the erosion penetrates deep to destroy dentine
...
This results in tooth ache and tooth is gradually
destroyed
...
Visit a dentist regularly for check up for healthier teeth
...
9
...
Digestion of food in mouth:
The process of mechanical and chemical digestion begins in mouth
...
It
contains an enzyme called ptyalin which acts upon starch to break them partly
into maltose (sugar)
...
Fig: 9
...
Digestion of food in stomach:
Stomach is a large bag-like, thick walled structure which stores food as it passes
down the oesophagus
...
Internally, its walls contain gastric glands which secrete gastric juice which
contains HCl and enzymes called renin and pepsin
...
mynoteslibrary
...
in food
...
Renin helps to curdle milk in infants
...
The thick walls of stomach churn up the
food
...
Peristalsis: The movement of food from oesophagus and onward up to the anus
takes place by means of an automatic movement or peristalsis (Fig: 9
...
Fig 9
...
Digestion and absorption of food in small Intestine:
Stomach is followed by a long, narrow tube called small intestine where the
remaining process of digestion is completed as well as the absorption of nutrients
from the digested food takes place
...
Through these two ducts, the secretion of liver called bile and the
secretion of pancreas known as pancreatic juice are poured simultaneously in
the duodenum upon the acidic chyme which is coming from the stomach
...
4
...
These proteins are useful as they speed up chemical reactions without being
used up by themselves
...
They are secreted by digestive glands
...
It is reddish brown in colour
...
For the process of
digestion, it secretes an alkaline, greenish yellow juice called bile which is stored
in a sac-like gall-bladder attached with it
...
It
contains some salts
...
It also
contains bile pigments
...
Bile helps in
breaking down of larger molecules of fats into small droplets
...
It makes the digestion of fats easier in the small intestine
...
Its secretion is called pancreatic juice
...
It contains sodium bicarbonate
and many enzymes
...
ii)
Trypsin: It acts upon the proteins to convert at into smaller peptides
...
9
...
3 Absorption of food in small intestine:
Duodenum is followed by ileum, the next portion of small intestine where the rest
of the digestion is completed by the enzymes present in intestinal juices secreted
by the glands present in the walls of small intestine itself
...
After the process of digestion of food is completed here, the digested food in the
form of soluble molecules glucose, fructose, amino acids, fatty acids, glycerol,
etc
...
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There are about 5 million villi in the ileum
...
The villi greatly increase the internal surface area of the ileum
...
Both blood capillaries and lacteal absorb the digested food
...
These capillaries join together to form a larger blood
vessel called the hepatic portal vein which carries the absorbed food to the liver
...
Lacteals of villi join together to form lymph vessels which finally
deliver the fats into blood stream through lymphatic system
...
23 Structure of Villus
Table: 9
...
secretion / enzymes and the
action
...
Gastric juice
Gastric glands in
stomach
HCl Pepsin Renin
Germicidal,
activates pepsin,
breaks down
proteins into
peptones
...
Bile
Liver
Nil
Turns acidic
chyme alkaline
and emulsifies fat
...
Amylase
Breaks down
starch into
maltose
...
Amino peptidase
Breaks down
peptides into
amino acids
...
Intestinal juice
Intestinal glands
in small intestine
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9
...
Depending upon the requirement of the cell, this
food can be used either to build new protoplasm or to obtain energy to perform
various activities
...
Our food consists of different components
...
This undigested food along with considerable
quantity of water is passed from the ileum into the large intestine
...
It consists of caecum, appendix,
colon and rectum
...
Meanwhile, the
intestinal bacteria cause fermentation of the undigested matter which is now
termed as faeces
...
9
...
9
...
However, some times due to the intake of contaminated food,
some disorders of gut may develop
...
Vomiting:
Whenever we take food containing harmful or poisonous substances, the contents
of stomach are expelled out through the mouth by antiperistaltic movements
...
It may occur when we over eat and helps to
expel out the food from the stomach giving us some relief
...
There are a number of other reasons for vomiting such as peptic ulcer,
appendicitis, many other diseases, psychological or emotional problems, travel
sickness, bad smells, pregnancy etc
...
Diarrhoea:
Diarrhoea refers to the condition of large number of watery motions
...
Due to continuous diarrhoea, the
body can lose large quantity of water which could be fatal if not rehydrated
...
In case of
diarrhea, they must be given continuously solution of ORS (Oral Rehydrated
Salt)
...
3
...
It is the condition in which there is infrequent or
difficult passing of dry, hard faeces occurs
...
It is a disorder of large intestine which absorbs excessive amount of
water from undigested food
...
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Appendicitis:
It is the inflammation (burning, painful sensation) of the appendix associated with
vomiting and abdominal pain
...
In such a case, physician must be consulted irnmediately for
diagnosis and treatment
...
5
...
These are minute, thread
like worms which live in the large intestine of man
...
It produces severe itching
around the anus
...
Such contaminated hands can cause reinfection of the same
person or others who take food or drink contaminated with the eggs
...
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Living organisms can be divided into two groups on the basis of their
modes of nutrition i
...
Autotrophs and heterotrophs
...
Simple sugar, starch and glycogen belong to a group of compounds called
carbohydrates
...
Proteins are building as well as biocatalyst molecules of the body
...
In
this process a plant can build sugar by taking CO2, H2O in the presence of
chlorophyll and light
...
Solar energy is converted into chemical energy in the form of ATP and
NADPH2 which is utilized during dark reaction for the fixation of CO2
...
Natural and artificial fertilizers are the source of mineral nutrients for
plant
...
Animals can not prepare their food from simple inorganic substances and
hence are all heterotrophs
...
Minerals ensure proper growth and functioning of the body
...
Malnutrition develops due to intake of inappropriate quantities of food
...
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Fill in the blanks with appropriate terms:
i)
Ready source of energy in the cell is________
...
iii)
The process of conversion of light energy into chemical energy
is called___________
...
v)
Another name of dark reaction is____________
...
vii)
Indigestible cell walls of plant cells is called_________
...
ix)
The part of teeth projected above the gum level is called________
x)
Starch breaks into maltose through the action of enzyme_______
2
...
ii)
Fats and oils are the consendation products of amino acid
...
v)
Widely used garden inorganic fertilizer is called 6-12-6
...
vii)
Calcium is required for the formation of blood
...
ix)
Carbohydrates are digested in stomach
...
3
...
(a) Lipids
(b) Carbohydrates(c) Vitamins
(d) Proteins,
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4
...
iv)
Write a note on chemical fertilizers of plants?
v)
What is roughage and how it is related to our health?
vi)
What is mal-nutrition? Why is it a health problem?
vii)
Write a detailed note on balanced diet
...
ix)
What is tooth decay?
x)
Explain the role of liver in the digestion
...
5
...
iii) Photosynthesis
vi) Saprophyte
ix) Pasteurization
xii) Appendicitis
Distinguish between the following:
i)
Autotrophs and heterotrophs
ii)
Light and Dark reaction
iii)
Protein and carbohydrate
iv)
Carnivore and Herbivore
v)
Digestion in stomach and digestion in intestine
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To keep the candle of life
burning exchange of O2 and CO2 inside and outside the body is a must
...
ATP and its importance
...
Aerobic and anaerobic respiration
...
Gaseous exchange in plants and animals
...
Effects of smoking on respiratory system;
Respiration may be defined as, “a process that liberates chemical energy
from organic molecules when oxidized
...
Nutrition is also a process of acquiring food
...
Food molecules
are bonded chemically, they require some energy for bonding
...
These bonds are broken and the energy is released
...
The energy obtained through respiration is
utilized to perform all the body functions, like cell division, growth, movement
etc
...
1 ADENOSINE TRIPHOSPHATE (ATP) FORMATION
All the living organisms from bacteria to human beings are always in need of
energy
...
As the cells can use energy only in the
form of ATPs so they are often called currency of energy and to carry out the
continuously going on metabolic activities a constant supply of ATP molecules is
always needed
...
Each ATP molecule, chemically, consists of
an organic component adenine linked to a ribose (5 carbon sugar) to form
adenosine to which is attached a chain of three inorganic phosphate groups
...
It supplies energy
to every energy consuming process anywhere in the cell
...
1 Structure of ATP
Chemically ATP is hydrolysed to ADP by enzyme ATPase releasing a phosphate
and liberating 30
...
3 Kcal) of energy
...
When the energy is made available, by oxidation of food, ADP takes this energy
to be converted to ATP that is to say that it becomes charged once again
...
About 1100 KJ (263 Kcal) are available in the form of ATPs whereas
the rest is lost as heat energy
...
2 ATP- ADP Cycle
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2 RESPIRATION AND BREATHING
At one stage when our knowledge about cell metabolism was not adequate,
respiration was considered as only the process of inhaling oxygen and exhaling
carbon dioxide
...
i) The breathing or gaseous exchange, takes place through the respiratory
surface by diffusion, either directly or through some transport medium like blood
and does not involve any release of energy
...
Thus both the steps of cellular respiration and breathing go together as
two separate steps but integral processes for the release of energy
...
3 CELLULAR RESPIRATION
Cellular respiration also called tissue respiration takes place within the cell
...
It usually requires oxygen and is called
aerobic respiration
...
10
...
1 Aerobic respiration:
This is the usual mode of respiration in plants and animals
...
The end-products are carbon
dioxide and water
...
Chemical equation;
Glucose + Oxygen
Aerobic
respiration
Carbon dioxide + Water + Energy (2827 KJ)
10
...
2 Anaerobic respiration:
Anaerobic respiration also called fermentation, takes place in some bacteria, fungi
and endoparasites
...
The end-products of anaerobic respiration in
bacteria and fungi are ethanol (ethyle alcohol) and carbon dioxide, whereas in
animals lactic acid is produced
...
Chemical equation;
In bacteria and fungi,
Glucose
Aerobic
respiration
Ethanol + Carbon dioxide + Energy (210 KJ)
In animals:
Glucose
Aerobic
respiration
Lactic acid + Energy (150KJ)
10
...
3 Importance of Anaerobic respiration:
As stated earlier, anaerobic respiration takes place in some fungi, bacteria and
endoparasites
...
Endoparasites especially the gut parasites respire anaerobically as no
free oxygen is available
...
mynoteslibrary
...
Fermentation:
The anaerobic respiration of fungi and bacteria is commonly known as alcoholic
fermentation because in the absence of oxygen glucose is broken down into
ethyl alcohol and carbon dioxide
...
Human muscle cells make ATP by lactic acid fermentation when oxygen is
deficient
...
This occurs during prolonged heavy exercise, when sugar catabolism
for ATP production surpasses the muscles supply of oxygen from the blood
...
The lactic acid that accumulates as a waste product may cause muscle fatigue
and pain, but is gradually carried away by the blood to the liver where it is
converted back to an energy releasing compound pyruvic acid and glycogen by
the liver cells
...
4 COMBUSTION, RESPIRATION AND PHOTOSYNTHESIS
Combustion is the process of burning
...
are burnt in
the presence of oxygen, producing carbon dioxide and water
...
It is an exothermic chemical reaction
...
When oxygen was discovered as the agent for combustion, it was known that the
food is burnt within cells in the presence of oxygen
...
However, the difference between the combustion and respiration is that the
combustion takes place in one go, releasing the entire energy as the heat, which
may be utilized or is lost into the environment
...
Each step is under the control of a specific enzyme, releasing
energy in small amounts which can be stored in the form of ATPs
...
3 Relation between cellular respiration and photosynthesis
Photosynthesis, another metabolic: process, is just opposite to combustion
...
In
photosynthesis, organic substance is synthesized from carbon dioxide and water
in the presence of sunlight energy and chlorophyll
...
Combustion is exothermic and releases energy,
photosynthesis is endothermic and absorbs energy
...
Photosynthesis takes place only in the green parts of the plant body having
chlorophyll, whereas respiration takes place in all the living cells of plants and
animals
...
Photosynthesis takes
place during the day time only, where as respiration takes place day and nignt
...
Respiration is an oxidation reaction whereas photosynthesis is a reduction
reaction
...
Chemical equation;
In respiration,
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5 GASEOUS EXCHANGE
Exchange of carbon dioxide and oxygen between the environment and organism
is termed gaseous exchange
...
This is necessary to allow the cells to obtain the gases needed for
metabolic processes and to facilitate the removal of gaseous metabolic waste
...
Diffusion gradient,
large respiratory surface area and a moist surface membrane
...
Gaseous exchange takes place in all
organisms by diffusion directly or indirectly
...
5
...
Except the root, the whole plant body is covered by a water
proof cuticle to check the evaporation of water, but at the same time prevents
gaseous exchange
...
Oxygen also enters
and dissolved in water from the soil through root hairs
...
Stomata:
Stomata (sing: Stoma) are pores in the epidermis of leaves and stems of plants
...
The inner wall (the wall lining the pore) is thicker and less elastic than the outer
wall
...
If water flows into the guard cells, they expand opening the
pore
...
Fig: 10
...
Under natural conditions stomata open at day time and close at night
...
Gaseous exchange in leaves:
Leaves are the chief organs of gaseous exchange as the stomata are most
numerous in the leaves, usually in the lower epidermis in dicotyledons
...
Diffusion inside the stoma:
Once inside the leaf, the gases pass through the sub-stomatal chambers into the
inter-cellular spaces of the mesophyll from where it diffuses into the cells
...
10
...
2 Gaseous Exchange in Animals
Like plants all animals exchange gases for respiration
...
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A unit
volume of air contains far more oxygen in it, than an equal volume of water
...
Animals show a great variety of form and structure, but the functions of life are
the same
...
As the form of organisms becomes more and more
complex, their functions also become complicated to achieve the maximum
efficiency
...
In Poriferian and Cnidarians all the cells of both the layers are in contact with
the water so each cell is able to exchange gases
...
This is
facilitated by the flatness of the body which increases the surface area to volume
ratio
...
The oxygen diffuses through the body surface into
the blood circulating under the skin, where it combines with the haemoglobin and
is carried to all the parts of the body
...
Molluscs, arthropods, echinoderms and vertebrates have developed
respiratory organs through which gaseous exchange takes place
...
Gills:
Gills are respiratory organs of aquatic animals, which are in direct contact with
the surrounding water
...
Each gill has a number of membranous
folds called lamellae, which are richly supplied with blood capillaries
...
5 Gills
The oxygen of the surrounding water which enters through mouth and bathes the
gills diffuses into blood and carbon dioxide of the blood diffuses out
...
Tracheal tubes:
The Tracheal tubes are found in terrestrial insects, which form a network of
ramifying troubles through out the body forming a tracheal system
...
This is much faster than diffusion of
dissolved oxygen through the tissues and permits high metabolic rates
...
mynoteslibrary
...
A number of paired holes called spiracles are present on the sides of thoracic
and abdominal segments which lead air into branched tubes called tracheae
...
In
each segment the tracheae branch into numerous smaller tubes called
Tracheoles which ramify among the body tissues ending blindly
...
At rest the tracheoles are filled with watery fluid through which
gaseous exchange takes place in dissolved state
...
Fig 10
...
Each book lung consists of a compressed sac like cavity having numerous
folds or lamellae which are attached to the inner side of the chamber and are
arranged like the leaves of a book
...
Fig 10
...
These are
amphibians, reptiles, birds and mammals
...
Leading from each lung is a short tube the bronchus
...
The ventilation
takes place by the up and down movement of the floor of buccal cavity
...
Ventilation occurs
by the movement of the ribs
...
Extending from
bronchioles are large thin-walled air-sacs
...
They
are remarkably efficient structures which fulfil the function of gaseous exchange
with minimum water and heat loss
...
6 HUMAN RESPIRATORY SYSTEM
The human breathing system consists of a pair of lungs and established system of
tubes for intake and removal of air through the nose
...
The floor is made up by the
diaphragm
...
The nose and mouth are separated by the palate so that one can breathe
through nose even when eating
...
It has mucus producing ciliated lining and numerous blood vessels close to the
surface
...
At the same time it is also cleaned, as the dust particles and
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The air the passes into a long wind pipe, the trachea about 12cm long
...
The opening of the
larynx is called glottis having a cartilaginous flap like structure epiglottis which
closes the glottis during swallowing of food and water
...
Fig 10
...
Each bronchus enters a lung,
where it splits and respilts into numerous branches
...
The walls of the alveoli
make the respiratory surface which is surrounded by the blood capillaries
...
10
...
1 Ventilation:
Ventilation means movement of air in and out
...
Breathing which takes by the movement of the chest,
can be divided into two steps inspiration and expiration
...
Expiration or exhalation is the forcing of air out of the lungs
...
This is brought about by two set of muscles the external and
internal, intercostal muscles and the diaphragm, which is a large sheet of muscle
...
At the same time the external intercostal
muscles contract
...
Together these
movements increase the volume of the thorax
...
Fig 10
...
At the same time the external intercostal
muscles relax and the rib cage of drop down again into its normal position
...
The internal intercostal muscles are used when breathe more forcefully like coughing
...
It also performs
the vital function of removal of toxic carbon dioxide from the body
...
mynoteslibrary
...
10
...
2 Composition of inhaled and exhaled air:
Oxygen
Inhaled
21%
Exhaled
16%
Carbon dioxide
0
...
Carbon dioxide brought by the blood is
released across the gaseous exchange
surface
...
Water evaporates and is lost as air
breathed out
...
As the exhaled air contains 16% of oxygen mouth to mouth breathing is possible in case of
emergency
...
6
...
Our heart beat and blood circulation become faster
...
The heart and lungs cannot supply oxygen to the muscles any faster
...
This energy debt is met by anaerobic respiration
...
This does not release much
energy, but a little extra might make all the difference
...
The deposition
of lactic acid makes the muscles fatigue and one feels tired
...
The amount of oxygen needed to
remove this lactic acid from the muscles is called the oxygen debt
...
10
...
10
...
1 Smoking
Smoking affects the lungs
...
Non-smokers are also affected if they spend much time in a room with
people who are smoking
...
These
are nicotine, tar and carbon mono-oxide
...
Nicotine is addictive
...
It increases the heart beat and blood pressure and causes heart diseases
...
Where as carbon mono-oxide is
poisonous
...
7
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mynoteslibrary
...
It is the inflammation of the bronchial tubes, which may be caused by smoking or
by bacterial infection
...
Extra mucus is produced
and the cilia stop beating
...
If the tubes become infected, the person may get
chronic bronchitis; chronic means long lasting, so the disease persists
...
7
...
It can be diagnosed by chest X-ray
and sputum test
...
B was one of the most common causes of death,
but modern medicine has now nearly cured it
...
7
...
B as the major killer
...
This blocks them, so breathing
becomes more and more difficult
...
If a growth is visible, it is removed by surgery or may be destroyed by
radiation therapy
...
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Some of the energy is stored in the form of ATPs, the rest escapes as heat
energy
...
Aerobic respiration takes place in the presence of free oxygen, releasing
maximum energy
...
Respiration is a catabolic exothermic reaction where as photosynthesis is an
anabolic endothermic reaction
...
Most of the gaseous exchange in plants takes place through leaves either
directly or through stomata
...
Human breathing system consists of a pair of lungs and the associated
tubes
...
Bronchitis may be caused by smoking, tuberculosis is caused by a
bacterium
...
1
...
The process which liberates chemical energy stored in food is
called________
...
Energy can only be used by organisms in the form of________
iii
...
iv
...
Accumulation of________ causes the muscle to fatigue
...
Respiratory reactions take place in ________
...
Gaseous exchange in plant chiefly occurs through________
...
________ are the respiratory organs in fishes
...
gases takes place in lungs
...
The amount of oxygen required to remove the accumulated lactic acid
from the muscle is called________
...
Write whether the statements are true or false
i
...
ii
...
ATPs are the currency of energy of an organism
...
Respiration and combustion are somewhat similar reactions
...
Stomata are the places of exchange of gases in plants
...
Tracheae are the respiratory organs in insects
...
Movement of air in and out of the body is also called ventilation
...
Photosynthesis is catabolic reaction
...
ATPs are synthesized in mitochondria
...
Fermentation is a process of anaerobic respiration
...
Encircle the appropriate answer:
i)
Respiration take place in
a) Parenchymatous cells
b) In leaves cells
c) All cells
d) In root cells
ii)
What is the importance of respiration in plants?
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...
6
...
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vi)
Plants gain weight due to
a) Respiration
b) Photosynthesis
c) Transpiration
d) None of the above
vii)
The respiratory organs of insects are
a) Flame cells
b) Malpighian tubules
c) Tracheae
d) Lungs
viii)
The intake of O2 and release of CO2 by blood passing through the
capillaries of the alveoli are brought by
a) Diffusion
b) Osmosis
c) Active transport
d) None of them
ix)
Tuberculosis is causes by
a) Virus
b) Bacteria
c) Worm
d) None of the above
x)
Cigarette smoke contains
a) Nicotine
b) Tar
c) CO
d) All of them
Write detailed answers of the following questions:
i)
Describe the breathing system of man
...
iii)
How does gaseous exchange take place in plants?
iv)
What are the disorders of respiratory system? How is health risk
associated with cigarette smoking?
v)
What is cellular respiration? Explain its types with the help of
chemical equation
...
vii)
Explain inspiration and expiration
...
Write short answers of the following questions:
i)
What are ADP and ATP? What is their importance?
ii)
What is the importance of anaerobic respiration?
iii)
Why do people have to breathe deeply after vigorous exercise?
iv)
Trace the path of exchange from air to alveoli of man
...
mynoteslibrary
...
iv)
v)
Combustion and respiration
Respiration and expiration
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Title: Secondary Stage Biology Book 1 For Class 9
Description: complete notes with heading
Description: complete notes with heading