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Biology Exam Notes
SNC2DR

Intro to Cell Structure
What is Life?
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All living things grow
All living things reproduce
Living things adapt and evolve
All living things respond to stimuli
All living things consume energy, gases, nutrients, and produce waste, they metabolize
All living things consist of cells

3 Postulates of Cell Theory
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


All living things consist of cells
Cells can only come from pre-existing cells
Cells are the simplest structures which can survive on their own

The Prokaryotic and Eukaryotic Cells



The first cells discovered were the Prokaryotic Cells
The more complex they became they turned into Eukaryotic Cells

Prokaryotic Cells:

Eukaryotic Cells:

Smaller in size
Less complex, they don’t have nuclear membrane,
only DNA free floating inside, and have few
organelles
Less evolved, appeared earlier on earth
All prokaryotic cells are unicellular organisms,
specifically bacteria
...
All multicellular organisms consist of
eukaryotic cells
...

 Organelle: A structure within the cell that performs a specific function for the cell
...
Nucleus
is also responsible for the cell reproduction
...


Nuclear
Membrane

Protects nucleus, semipermeable, controls the flow of substances in and out
...
Looks like a been with a wave wall inside
...
Made of the same material as the
cell membrane
 In plants: presses against the wall to keep cell “inflated” and therefore
helps to keep the entire plant upright as a stock of rigid cells

Chloroplast



In plants only: organelle responsible for photosynthesis
...
Has its own DNA
...
g
...
(not
egg or sperm cells)
...
When they divide, new cells are identical to the parent
cell
...

Cells spend most of their time in this stage
...
Some cells (like neurons in our spinal cord) divide once in 50 year (practically, you
cannot get them replaced, if they are damaged)
...
In 5 year period, most of our body cells
get replaced

-

Mitosis
Division of nucleus
...


Prophase, Metaphase, Anaphase, Telophase

-

Cytokinesis
Division of cytoplasm, organelles, cell membrane and formation of two separate cells
...
It is
uncoiled and long and
‘tangled’
...

This form is easier to
separate and divide
during mitosis
1
...
Telophase

Spindle fibres attached to
centromeres



3
...

Metaphase

HOW????  spindle fibres’
microtubules shorten, pulling
the chromatids to the poles)



Last mitotic phase – begins
when the chromatids reach
the poles
Each chromatid is now called
a chromosome
Chromosomes begin to
unwind and become less
visible (back to chromatin)
Nuclear membrane starts to
re-form
Nucleolus becomes visible






Cytokinesis







Cytokinesis is the separation
of the cytoplasm and the
formation of two new
daughter cells
Occurs after mitosis
Cytoplasm (and contents)
divides
Cell membrane forms to spilt
into two cells

Cancer
Mutation is a change in DNA
Mutation may have positive and negative outcomes
...
E
...
there are enough nutrient, appropriate environmental conditions such as
temperature or else)
...

If DNA mutation is unrepairable cell does destroy itself to prevent the wrong version of DNA to continue
dividing multiplying and carrying on the moistakes
...

Tumour is a group (a mass, a cluster) of cells produces by the uncontrolled division
Tumours Type
Ability to spread
Cancer or not
Danger level
Rate of growth

Malignant

Benign

Spread over the blood stream

Stays at one spot

cancer

Not cancer

May cause death of entire organism,

Do not cause death
...

List of Few Carcinogens




Some chemicals such as those in tobacco smock, asbestos insulation, some solvents
Some energetic radiation starting from UV in large amounts or x-ray even in little amounts
Viruses because they destroy other cells breaking down their DNA and letting them go

Some foods help us to get harmful chemicals out of our body, such as broccoli, garlic, and others Healthy
life style such as healthy diet, not smocking, not being under the sun for a prolong time helps to avoid
cancer
...
Mutation may happen out of blue or may be inherited
...


Cancer Diagnosis


Endoscopy
- They put a tube down your mouth
- Take a video of the tissues
- They take a swab of the tissue to confirm
- They test it just to double check



Disadvantages
It only limited to certain tissues/ organs

Ultrasound
- Uses high frequent sound waves, works the same way as echo- locator
- Shows soft tissues such as liver, heart
- It is non-invasive and inexpensive
- A pregnant women could not be harmed

-

Disadvantages
May not determine all tumors in all classes

 X-Ray

-

Highly energetic radiation that penetrates soft tissue but shows well bines and abnormalities
in lungs
It may damage DNA
It is first used for lungs, and can show a mass in the lungs

-

Disadvantages
Sometimes the mass found isn’t even sometimes cancerous and further studies are needed

-

 CT or CAT Scan
-

Multiple x-rays of the body from different angles
Able to show cross section

 MRI
-

Uses powerful magnetic fields resonating with atoms nuclei in a body
It provides a difference between the soft tissue of the body, the heart and cancers

-

Disadvantages
They don’t use ionizing radiation

Cancer Treatment
 Surgery
-

Physical removal of the cancer
The only successful way to get rid of the cancer
Only works if the cancer hasn’t spread yet

 Chemotherapy
-

Effective because it reaches all the cells
It kills small undetected tumors
It doesn’t only kill cancerous cells but it also has side effects like hair loss, vomiting etc
...
(p
...
There is a chance that cancerous may be
killed by chemotherapy, that includes all cells including bone marrow stem cells
...
Bone marrow stem
cells are transplanted form a matching donor
...

Read the story on p
...
The
patient lost her trachea due to tuberculosis
...
Then stem cells were introduced
on the trachea and they manage grow, differentiate and regenerate a new trachea for the patient
...
Cellular level
2
...
Organ level
4
...
Organism level

Tissue: a group of specified cells that work together to perform a specific but limited
function
4 Tissue Groups
 Epithelial: lining of inside the body and outside the body
 Connective : throughout the entire body they help support, connect, and protect the
organism as a whole
 Muscle: designed to change their to contract
 Nerve: cells have long extensions in brain and spinal cord, it helps control all sensory
organs( called Neurons)
Organs: are groups of tissues working together to perform a specific complex function
Organ systems: a system of one or more organs that work together to perform a major
vital body function

Respiratory System
Respiratory system is responsible for
Breathing is mechanical gas exchange
Respiration is chemical gas exchange

Match the parts and organs of respiration system with the diagram
...


Nasal cavity

Lets air in/ filters out air

Mouth
Epiglotis

Its flap which allows the

Trachea

Allows air to travel through

Bronchus

Allows gas exchange/ lets air through

Lung
The role of Diaphragm:

Allows air to go in

Allows gas exchange/ performs repiration

Alveoli

Is a sac that stores oxygen

Circulatory and Respiratory systems work together
The role of Capillaries:
The capillaries allow gas exchange to occur between the bronchi
...


Transport substances around the body
 Moves absorbed nutrients from small intestines to all the body’s cells
 Carries waters form the body’s cells for disposal ( to the kidney, when we urinate)
 Carries CO2 to the lungs to be released into the air
 Moves disease fighting white blood cells to areas that have infections for viruses

2
...
Red Blood Cells

o
o
o

Make up 45% of the bloods volume
Contain hemoglobin
Hemoglobin is what akes blood red

2
...
Platelets

o
o

<1% of the blood’s volume
Tiny fragments of cells that are involved in the blood

o
o

55% of the bloods volume
Protein rich fluid that carries blood cells along

3
...
Taking in food
2
...
Digesting good
4
...
5 m long and wider than the SI
It Is wider which allows it to get rid of
bigger waste (soild matter)

Rectum

 That is where the waste gets stored

Anus

 Is the hole that the waste comes out from

Accessory
Organs:

 They kinda the digestive system throughout the
way but are not a major part

Liver

o

Secrets enzymes for digestion

Gold Bladder

o

Stores bile

o

Also secrets enzymes for digestion

Pancreas

Tissue Systems in Plants
Tissue is a group of specialized cells who work together
Meristematic cells are
Meristematic cells are located:

Plant Tissues:
Tissue Group
and its general
function

Tissue

Dermal Tissue –
tissue found
outside the
plant

Epidermal tissue

Location, Special Features and Functions

Periderm tissue

Vascular tissueit’s a
transportation
system that
moves water,
minerals, and
other chemicals
round the plant

o

Thin layer of cells which cover the non – woody
parts or surfaces of a plant
Like the leaves

o
o

Tissues that cover the woody parts of the plant
Like the bark, stems, and roots

Xylem

o

Transports water and minerals form the roots to
the leaves and stems
Only moves in a upward direction
Usually passive cells as they are dead
Are hollow so they can transport more water etc
...

2
...

4
...


Organism
2 body systems
Parts
Tissues
Specialized cells

Label two body systems of the plant and some of its parts
...


Shoot system

Root
system

Body
System
Root

Shoot

Location

Structure

Function

The part of the
plant that grows
below the
ground

o

o
o

The part of the
plant that grows
above the
ground

o

o

o

Can have one or
more roots
Contain root hairs:
tiny extensions of
the tissues that help
with absorbing
Made of various
parts
Leaf, the flower and
the stem

o

o
o

Anchors the plant
Absorbs water and
minerals from soil
Stores food

It conducts
photosynthesis
And reproduces sexually



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