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BIOLOGY REVISION
12
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16 – CB1 KEY CONCEPTS







allow one to see what isn’t visible to the human eye
Discovered in the 17th century by Antony Van Leeuwenhoek
Maximum magnification usually x1500
Use of light beams
Lower resolution than electron microscopes

MAGNIFICATION – how many times bigger the image is in comparison to the original image
RESOLUTION – the minimum distance between two images before they aren’t recognised as
separate images (clear)
Using a light microscope –






Select the lowest power objective lens (x4)
Place slide on stage, fasten with clips to secure – stain/coverslip specimen if necessary
Look through objective lens, turn coarse focus knob to move down/up into focus
Use fine adjustment to enhance vision
Now change objective lens, make sure not to touch stage

Precautions to take –







Never use sun/mirror as light source – will damage eyesight
Start with lowest objective lens
Make sure slide is secured properly
Make sure slide is in central focus
Only use fine focusing wheel with high power objective
When finished, raise tube/lower stage, select lowest objective lens and remove slide

Drawing cell diagrams from microscopes –







13
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16




Must be in pencil
Title must be written
Magnification/scale given
Labelling done with ruler
Shading shouldn’t be used
Clear and realistic (don’t draw what can`t be seen, even if would be there)

– ELECTRONMICROSCOPES AND CONVERSIONS (CB1A
...
9
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9
...
Within sperm cells:
ACROSOME – found in the sperm cells head, strong enzymes that help break down the eggs jelly
surface, helps it burrow itself into the egg
HAPLOID NUCLEUS – one set of chromosomes (23), rather than two
LONG TAIL – helps the sperm swim towards the egg
MITOCHONDRIA – where respiration occurs, provides energy

2
...
Within a ciliated epithelial cell:
FINE, HAIR-LIKE EXENTIONS – move things across the
surface
DIPLOID NUCLEUS – contains two sets of chromosomes
(46)

Work of the lungs specialised adaptions against dirt –





Epithelial cells line tubes leading towards lungs (trachea)
Mucus traps dirt/dust/bacteria
Cilia move music along tubes away from the lungs
Nasal hairs also keep out dust and larger microorganisms

5
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16 – INSIDE BACTERIA (CB1d)

(DNA in plasmids and circular chromosome)
EUKARYOTIC: cell with a nucleus (animal, plant cells)
PROKARYTOIC: cell with no nucleus (bacterial cell)
6
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16 – ENZYMES AND NUTRITION (CB1Be)
ENZYMES – biological catalysts that speed up reactions however are never used up
METABOLISM – all the reactions that take place in our bodies (the breaking and building of
substances)
SYNTHESIS – to build a large molecule from smaller ones
POLYMERS – a substance made up of very long molecules containing repeated groups of atoms
MONOMERS – a small molecule that can join with others of the same kind to make a polymer

/glucose

synthesis – small into large molecules
Digestion – large into small molecules
10
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16 – ENZYMES CONTINUED (CB1e)

ACTIVE SITE – the space in an enzyme where the substrate fits during an enzyme-catalysed
reaction
SUBSTRATES – a substance that is changed during a reaction
PRODUCTS – a substance formed from a reaction
DENATURE – an enzyme where the shape has changed so much that the substrate no longer fits
in it & the reaction can’t take place
LOCK & KEY MODEL – model that describes the way an enzyme catalyses a reaction when
substrates and active site combine
SPESIFIC – when an enzyme only reacts with one kind of substrate

((substrate))
 Starch
 Protein
 Fats

((enzyme))
amalyase
protase
lipase

((products))
glucose/maltose
amino acids
glycerol/fatty acids

27
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16 – ENZYME ACTIVITY (CB1G)
1
...
One substrate molecule fits neatly into the active site of the enzyme, like a key
into a lock
3
...
The product molecules are a different shape to the substrate, so they no longer
fit into the active site and are then released
5
...


CB1G PH AND ENZYME PRACTICAL –
“measuring the effects of different pHs on enzyme action – how long it takes for amylase
solution to break down starch”
METHOD –
1
...
Heat water in beaker over Bunsen burner to 35 degrees
3
...
Use different syringe to add 3cm3 of starch solution to boiling tube
5
...
Use continuous sampling to measure how long it takes for the amylase to break down
the starch
7
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When solution remains browny-orange, starch is no longer present
9
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11
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Diffusion
Osmosis

High-low
High-low

Down
Down

Active or
passive
process
Passive
Passive

Active
transport

Low-high

Against

Active

Examples
Gas exchange in lungs
Movement of water
into hair-root cells
Movement of minerals
in hair-root cells

CB1H CORE PRACTICAL – OSMOSIS IN POTATOES
(Measuring osmosis in potatoes by comparing mass before and after soaking in sucrose)
1
...
Fill test tubes with different concentration of sucrose
solution and label each
3
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Leave in solution for at least 15 mins
5
...
Calculate change in mass with corresponding
concentration
Potato chips in the different solutions –



Dilute solutions – drawing in water as higher concentration inside potato in comparison
to outside (causes increase of mass)
Concentrated solutions – water lost from potato due to higher concentration in solution
that in potato (causes loss of mass)
(more concentrated the solution, greater the loss of mass)

CALORIMETRY – measuring the change in energy of a chemical reaction based on the
amount of heat lost or gained (exo/endothermic) – based on temperature change
CALORIMETER - device used to measure the quantity of heat transferred to or from an
object
...
11
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11
...

2
...

4
...

6
...


29
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16 – CB2D STEM CELLS
STEM CELLS – unspecialised cells that can divide to produce more stem cells or different
kinds of specialised cells (no hay flick limit)
HAYFLICK LIMIT – the limit of how many times a cell can divide
MERISTEMS – a cluster of un-specialised cells at the tip of the roots or shoots that
consist of stem cells which ensure growth in plants
Embryonic stem-cell:






From an embryo (unfertilised egg cell) to an zygote (fertilised)
Divide repeatedly to produce any type of cell
Different parts of the embryo become different organs
Can produce any type of specialised cell and repair damaged tissue such as nervous
tissue in the spinal cord
Can cause cancer due to potential ongoing division



Ethical issues due to embryos destroyed in process and chance of rejection from bodyattacked by patient`s immune system due to foreign cells

Adult stem-cell:




Taken from a fully developed organism, do not require destruction of embryos and
won’t be rejected if taken from individual themselves
Stem cells can only reproduce the type of specialised cell that was in the tissue it was
extracted from (limited differentiation)
Allows tissue to grow and replace damaged cells, however only of the same type

5
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16 – CB2E THE NERVOUS SYSTEM



Central nervous system – brain and spinal cord (CNS)
Peripheral nervous system – consists of any other neurons that carry signals to and from
the CNS

Reacting to a stimulus –
1
...
RECEPTORS (convert)
Cells that receive a stimulus and converts it into electrical impulses, to be sent to the CNS
3
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BRAIN/ SPINAL CORD (receives)
Elements of the CNS
5
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EFFECTORS (parts – absorb)
Muscle or gland in the body that reacts to the impulse when received
7
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Speeds up impulse
transmittions, ability to jump over synapses, insulates the neuron from surrounding tissue and
ensure the signal keeps its energy
...
1
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Consists of two divisions and provides genetic variation within the offspring which is
crucial for survival
...
This individual is genetically different from its
parents
...
1
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A – Adenine
2
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C – Cytosine
4
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1
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Cystic fibrosis –
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

Genetic disease
Caused by recessive allele
Mutation in gene causing thicker mucus to build up
Clogs airways and lungs, difficult to breathe
If only one recessive allele is present, individual is a carrier

17
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17 – GENE MUTATIONS

MUTATION – order of bases within DNA is re-arranged (change in sequence), effects
proteins produced

-

As well as genetic mutations, environmental factors can also cause these, including
smoking, radiation, foods and x-rays
Some can be harmful (having negative effects) – cystic fibrosis, Hd
Some can be neutral (no change in protein)
Some can be beneficial (positive effects) – giraffes with long necks

23
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17 – HUMAN GENOME PROJECT
HUMAN GENOME – sequences of bases on all human chromosomes


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In 2003, first human genome was recorded
Represents sequence of DNA within a cell
Comparing human genomes has proven over 99% of DNA bases in different people are
the same
Allows genes to be studied, preparation for future illnesses and troubles and more
efficient medication to be distributed

VARIATION VARITATION – ways in which we differ from one another due to mutations and DNA sequences
INHERITED VARIATION – both gametes that fuse are different therefore causing variation
ENVIRONMENTAL VARIATION – conditions in ones surroundings and acquired characteristics
causes variation
Inherited
Eye colour
Blood group
Genetic diseases
Natural hair colour
Attached ear lobes

Environmental
Fitness
Accent
Speed

Both
Strength
Height
Intelligence
Skin colour
Personality

CONTINUOUS VARIATION – usually environmental and inherited genes, endless possible values
(height, weight, foot length) – normal distribution (bell shaped)
DISCONTINOUS VARIATION – genetic characteristics/genes that have limited sets of possible
values (blood group, eye colour, and tongue rolling) – bar graph

6
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17– EVOLUTION
EVOLUTION - the gradual change in characteristics of species over a long period of time
FOSSILS – preserved remains of organisms from thousands of years ago
...
ARDIPITHECUS VAMIDUS (Ardi)
 Lived around 4
...
2 m tall
 50 kg
 Bone structure indicates upright posture
 Long arms and ape-like feet (climbing trees)

2
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2 million years ago
 1
...
HOMOHABILIS (handy man)
 lived around 2
...
4 million years ago
 Short with long arms
 Primitive tools introduced
 Human-like characteristics
4
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8-0
...
79 m tall
 Heavily built
 Human characteristics
Older tools – used for skinning and cutting and up meat
Newer tools – more sophisticated, used for carving
9
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17 – DAWIN`S THEORY
GENETIC VARIATION - the variation of characteristics due to differences in genes
ENVIRONMENTAL CHANGE – conditions in an area which change
NATURAL SELECTION -advantageous characteristics some organisms possess which gives them
a better chance of survival
INHERTIANCE – survivors breeding on their variations to their offspring
EVOLUTION – gradual change of an organisms characteristics over a long period of time
Peppered moths –
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During the 1950`s in London, pollution increased drastically
Those with dark wings were better adapted for survival
This was because they were able to camouflage, meaning their colour was essentially an
advantageous characteristic
Therefore they increased in number due to the lighter moths dying out
The lighter moths weren’t able to camouflage and therefore were eaten by predators at
a much quicker rate

SPECIATION – the formation of new species due to evolution

27
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17 – CLASSIFICATION
CLASIFICIATION – labelling something/putting it into a certain category – 8 Main levels known
as taxa

BIONOMINAL SYSTEM – way of naming organisms using two Latin words, should be in italics
and underlined – first word being the genus and second word being the specie
FIVE KINGDOMS – animals, plants fungi, bacteria/prokaryotes and protists
THREE DOMAINS –
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


Archaea (no nucleus, unused DNA)
Bacteria (no nucleus, no unused DNA)
Eukarya (nucleus, unused DNA)

MULTI/UNI CELLULAR
WITH/WITHOUT
NUCLEUS
FOOD?

CELL WALL?
EXAMPLES

ANIMALS
Multi
With

PLANTS
Multi
With

FUNGI
Multi
With

PROTISTS
Uni
With

Eating
other
plants
/animals
No
Mammal,
reptile

Photosynthesis

off other
dead/living
matter

x

Cellulose
Leafs, flowers

Chitin
Mushrooms

Some
Green algae

SELECTIVE BREEDING – process of intentionally breeding for certain traits




Whilst natural selection takes millions of years, selective breeding takes only a few
hundred, therefore is much quicker
Natural selection is caused by environmental pressure, whilst selective breeding is
caused by human pressure
The two contrast one another

BACTERIA
Uni
Without
x

Murein
Cyanobacteria

Process of selective breeding
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
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

Variation within a population
Desired characteristics identified
Animals with those characteristics are bred together
Offspring are then bred
This Is repeated continuously until desired trait is fully developed

ANIMALS
Quantity and quality of milk
Quality of meat
Quantity and quality of eggs
Yield (useful production)
Disease resistant
Quality of fur
Strength and speed

PLANTS
Production of fruit
Appearance
Taste of fruits
Yield (useful production)
Disease resistant
Lifespan length
Shortness of stems (durability)

BREED – group of animals of the same species that have different characteristics which make
them different to other members of their specie
VARIETY – group of plants of the same species that have characteristics that make them
different to other members of the specie
Problems with selective breeding –
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

Reduces genetic variation
Similar organisms can become prone to same diseases
Ethical conditions for animals (weight and size putting pressure on joints)
Domesticated animals become incapable of surviving in wild
Some alleles may be rejected and therefore will eventually die out, although
potentially serving purpose in future

2
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17– GENTIC ENGENERRING
GENETIC ENGENERRING - the process of removing a gene from one organism and inserting it
into the DNA of another organism



Organism will then be known as a genetically modified organism
This process is also much faster the selective breeding and natural selection

GM amongst crops
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

Pest resistant – produces toxins against pests
Disease resistant
Drought resistant
Longer shelf life
Frost resistant

GM amongst rice –
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Rice produced for countries with little fruit and vegetables (vitamin A)
adapted to produce proteins of Beta-carotene, making vitamin A
helps to fight against blindness (caused by lack of vitamin A) and death

GM goat and sheep –




future idea
goats and sheep to produce proteins in their milk
helps to fight and teat against human diseases

ADVANTAGES`
Could result in cheaper food
Provide bigger yields
Could grow in harsher conditions
Less chemical sprays necessary

DISADVANTAGES
Expensive to produce
Could cause allergies
Reduce biodiversity
Accidental transfer of new genes

Diabetes 1 cure –
-

Insulin is needed to regulate blood sugar levels
Lack of this causes diabetes
Insulin gene placed into bacteria which is then replicated
Enzymes needed to cut out useful gene from DNA and insert into bacteria’s DNA
Bacteria consists of plasmid and ends pair up with human DNA
2) Plasmids (the vector)
from bacteria are cut open
with the same enzymes and
left in the same manner

1) The first step is to cut a
useful gene out of an
organisms DNA (from
placenta) with a
restriction enzyme,
leaving sticky ends
(unpaired matches)

3) Copies of the useful
genes are mixed with the
cut plasmids
4) The sticky ends of
the genes and
plasmids match up
and are joined
together by a DNA
ligase enzyme

6) The bacteria now produce
the characteristic coded for by
the gene

5) Plasmids are
inserted back into
the bacteria

8
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17 - CB5A HEALTH AND DISEASE
GOOD HEALTH – more than simply feeling well, but at a state of complete physical (staying fit,
preventing harm), social (family/friends, communications, relationships) and mental (feeling
happy, positive) well being

Lack of
Protein
Vitamin c

Causes
Kwashiorkor
Scurvy

Vitamin d/calcium
Iron

Rickets/osteomalacia
Anaemia

Problems
Small muscles
Bleeding gums,
joint problems
Soft bones
Less/smaller red
blood cells

Cure with
Meat, fish, dairy
Citrus fruits and
some vegetables
Dairy products
Red meat, dark
vegetables

Excising in groups improving you’re Physical well-being – keeps you fit, excise
Social well-being – taking part in a group, improving social skills and building relationships
Mental well-being – helps to release stress and anxiety

DISEASE – an illness that prevents the body from functioning properly
COMMUNICABLE – any disease that can be spread from one person to another through
INCOMMUNICABLE – when a disease can`t be spread from person to person





One disease can increase chances of other diseases
Damages immune system, making you more prone to disease
Damages body`s barriers and defence system
Allows pathogens to enter body more easily

9
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17 – NON-COMMUNICABLE DISEASES CB5B
Causes –
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


Genetic – faulty alleles within DNA (cystic fibrosis, Parkinson’s)
Diet – poor diet/malnutrition (anorexia, anaemia)
Lifestyle – amount of exercise/drug intake (obesity, stroke)

Large alcohol consumption – requires liver to break down large sums of ethanol (drugs),
causing great damage (Leads to liver disease, cirrhosis)

CIRROHSIS – liver disease caused by over consumption of drugs and alcohol
DEFICIENCY DISEASES – an illness due to an insufficient supply of an essential dietary
requirement
Liver disease –
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



Ethanol is a toxic drug
Poisonous to body cells
Broken down in liver
Liver cells harmed and damaged
No longer work properly
Causes cirrhosis

Disease caused by lifestyle –
Over consumption of alcohol is a problem for:




Person who drinks it – effects health, increasing chance of death, costly
Family – potential influence, increase of stress/arguments, potential loss of family
member
Society – death rate increases, production of alcohol increases due to demand,
expensive health care

GENETIC DISORDER - Diseases caused by genetic mutations e
...
cystic fibrosis, haemophilia,
Duchenne muscular dystrophy
15
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17 – CB5C CARDIOVASCULAR DISEASE
CARDIOVASCULAR DISORDER – disease/conditions involving and affecting the circulatory
system (heart, blood vessels, brain)



Fats are crucial for insulation - store of energy, cushions/lines organs & vitamin
storage
Over consumption can lead to – artery restriction/blockage, heart diseases, strokes
and obesity
(Excess fat gets deposited under the skin and around organs)



Rise of obesity caused by - increase of technology decreasing ones physical activity,
fast food being cheaper and more efficient




Any BMI above 30 suggests individual is overweight
18-25 is a desirable, healthy weight

Waist: hip measurement –



Measuring abdominal fat which is closely related to cardiovascular disease
Higher the ratio, higher the chance of cardiovascular disease

Causes of CVD – obesity, lack or exercise, smocking, drug consumption, over exercise, high
blood pressure, high cholesterol, diabetes (type 2)
Preventing CVD – balanced/healthy diet, regular exercise, changing lifestyle if necessary and
maintaining healthy weight
-

More important to prevent rather than treat as can be fatal before treatment given and
reduces life expectancy

17
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17 – SMOKING AND DISEASE
HEART ATTACK – blood can`t access part of the heart due to blockage in vessel
STROKE – blood and oxygen can`t reach part of brain due to clot in vessel


Smoking can increase chance of stroke and heart attack due to it depositing fats in the
vessels, making it hard for blood to travel pass and reach heart/brain

Treating CVD –





Medicine – ACE (reduces blood pressure and stress on heart), aspirin (thins blood to
reduce chance of clot) and beta blocker (slows down heart rate and reduces its activity)
Angioplasty – balloon like structures inserted into vessels, expand to increase size and
stent used to maintain shape
Bypass surgery – new blood vessel used to replace faulty one
Heart transplant – replacing the faulty heart with a more healthy one

18
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17 – CB5D PATHOGENS
PATHOGENS – micro-organisms that spread disease (communicable)
SECONDARY INFECTION – an infection due to the immune system being weakened previously
by a different pathogen
1
...

3
...


BACTERIA – produce toxins that damage host tissue
VIRUSES – break open and destroy white blood cells
FUNGI – digest living cells and destroy them
PROTISTS – take over cells and break them down

Viruses causing disease –





Infect body cells
Take over body cells DNA
Begin to produce toxins
Damages cell when new viruses released

Bacteria causing illness –


Name of disease

Attack/inhibit body cells
Release toxins
Host organism

Type and name
of pathogen
Bacteria – vibrio
cholera

Main symptoms

Cholera

Humans

Tuberculosis

Humans and
animals

Bacteria –
m
...
5
...
5
...
skin
Chemical – hydrochloric acid, lysozyme fluids
Chemical/physical
Chemical

Protection
Hydrochloric acid

Where found
Stomach

Chemical

Lysozyme

Sweat, urine, saliva

Physical

Mucus

Physical

Cilia

Respiratory and
digestive system
Respiratory system

How it works
Kills micro-organisms
from contaminated
food/water
Consists of enzymes
that kill of harmful
bacteria by digesting
their cell wall
Traps pathogens
Brush away the
mucus with trapped
pathogens

SEXUALLY TRANSMITTED DISEASE – communicable disease spread during sexual activity


Chlamydia is caused by the bacterium, whereas HIV is caused by virus

How chlamydia can be spread –




Unprotected sexual activity
Getting sexual fluids in your eye
Transmittions from mother to baby during pregnancy via placenta

How HIV can be spread –





Unprotected sexual activity
Contact with blood from infected person
Transmittions from mother to baby during pregnancy via placenta
Breast milk from mother to baby

Prevention methods of HIV and chlamydia –





Use of condoms
Bottle-feeding baby of infected mother
Not sharing needles for injecting drugs
Screening reveals infection and medication given, more precautious

STI

Causative agent

How is it transmitted

Main symptoms

Prevention and
treatment

Chlamydia

Bacteria

Unprotected sex, sharing
of sex toys,

Pain when urinating,
unusual discharge, tummy
pain, bleeding and swelling
in the testis

Antibiotics, use of
condoms and dam,
not sharing sex
toys

Genital warts

Virus

Unprotected sex, sharing
of sex toys,

Swelling in genital area

HIV Vaccinations
to prevent,
freezing off waltz

Genital herpes

Virus

Sex

Pain when urinating, small
blisters around genitals,
vaginal discharge

Anti-viral
medicines

Gonorrhoea

Bacteria

Unprotected sex, sharing
of sex toys,

W – unusual discharge, Pain
when urinating, bleeding
M- Pain when urinating,
inflammation of foreskin
and pain in testis

Antibiotic
injection, use of
condoms, not
sharing sex toys

Syphilis

Bacteria

Close contact with
infected sore, sharing of
sex toys

Ulcers and sores, white
patch on mouth

Antibiotics, use of
condoms, not
sharing sex toys

HIV

Virus

Contaminated needle,
mother to baby during
pregnancy

Fever, sore throat, bodily
rash

Use of condoms,
not sharing sex
toys

Public lice

Bodily and sexual
contact

Use of condoms,
insecticide cream

Trichomoniasis

Sex

Itchy affected area,
inflammation, black powder
in underwear, blue spots on
skin
Pain when urinating, frothy
yellow discharge

Use of condoms
and dam,
antibiotics

8
...
17 – CB5G THE IMMUNE SYSTEM
Immune system consists of –








Tonsils and adenoids
Thymus
Spleen
Peyer`s patch
Bone marrow
Appendix
Lymph nodes

- In some cases, pathogens pass through the chemical and physical barriers, into the body
- Immune system becomes active in attempt to protect body
Two types of white blood cells –
1
...
LYMPHOCYTES – produce specific antibodies
ANTIGEN – proteins on the outside of all cells and virus particles, white blood cells are able to
detect pathogens because of their antigens (makes them recognisable)
ANITBODY – a protein produced by lymphocytes, attaches to specific antigen on a
microorganism and helps to destroy/neutralise it

Antibody

Antigen
cell
Immune response to a first-time infection by pathogen –
1
...
Pathogens in blood come in contact with lymphocytes, different variations have
different antibodies on their surface
3
...
Activated lymphocytes divide rapidly to produce many identical copies with the same
antibodies on the surface
5
...
Antibodies attach to pathogens and cause them to die
7
...
6
...
6
...
Pre-clinical stage of testing is done on cells or tissues in a lab to find out whether the
medicine gets into diseased cells and has desired effects
2
...
A small clinical trial is carried out on a few people to find out whether the medicine is
safe for humans and side effects are limited
4
...
7
...
This causes
them to open up the stomata, ready for
photosynthesis
...


CB6B – FACTORS EFFECTING PHOTOSYNTHESIS –
1
...

3
...

5
...


Light intensity
CO2 concentration
Temperature
No
...
e light), it is no longer a limiting factor, however others
remain
As temperature increases, rate also increases, up until it reaches the optimum
temperature whereby enzymes denature and rate falls

DIRECT PROPORTION – the two values correspond to one another, whereby one increases, so
does the other
INDIRECT PROPORTION – the two values are indirect to one another, whereby one increases,
the other decreases
Direct

Indirect

Inverse square law – used to work out new light intensity
L
...
O X D
...
N2
10
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17 – CB6C ABSORBING WATER AND MINERAL IONS
Function and Adaptations of roots (root hair cells) –







To absorb water and minerals from the soil
To anchor the plant in the ground
Large vacuole to store maximum amounts of water
Thin cell walls for increased efficiency
Hair like extensions to provide large surface area
Porous in order to let through water and minerals

What plants use water for –







Germination and growth
Softens seeds, making it easier for plant to push through
To perform process of photosynthesis
Maintains cells firm structure
Carries dissolved mineral ions
Transpiration – preventing plant from over heating

BUTTRESS ROOTS – large roots on the surface of the ground to keep the tree upright and trap
dead vegetation to provide nutrients for tree
-

CO2, H20 and O2 are needed for plant to stay alive, and are found in the air and water
Minerals needed for making amino acids – proteins for growth (Nitrate) and to produce
chlorophyll (Magnesium)

ACTIVE TRANSPORT – movement of particles from a low to high concentration, against
concentration gradient (requires energy – active/ATP)
OSMOSIS – movement of water particles though a semi-permeable membrane, from a high to
low concentration, down the concentration gradient (no additional energy required – passive)


In root hair cells, higher concentration of minerals than outside
MINERALS – ACTIVE TRANSPORT (from low to high)



In root hair cells, lower concentration of water than outside
WATER – OSMOSIS (from high to low)

-

Water through cell membrane – osmosis
Water through gaps in cell wall – diffusion

7
...
17 – CB6D TRANSPIRATION AND TRANSLOCATION
XYLEM CELLS – dead cells used to carry water and minerals from roots to rest of plants
PHLOEM CELLS – alive cells used to carry sucrose (made from glucose) from leaves to around
the plant
Formation of a xylem vessel -

1
...
Living cells are arranged on top of one another, eventually die and disintegrate – creates
long empty vessels which water can travel through easily
3
...
7
...
7
...
A to increase
rate of absorption
 Mitochondria for
active transport
 No cell wall at ends so
liquid can pass
through cells
 Dead cells with no
cytoplasm to form
tubes
 Pores to allow water
and ions to enter and
exit
 Thick side walls and
rings of lignin
 Pores to allow
movement of liquid
 Large central channel
in tube
 Mitochondria to
release energy to
pump sucrose
 Difference in cell wall
thickness causing
shape change

7
...
17- CB7A HORMONES
HORMONES – Chemical released in certain parts of body, carried within blood








Produced in endocrine glands
Act like messengers
Carried from organ to organ in blood stream
Isn’t very efficient (travels at rate of blood flow)
Every hormone has its own target organ and will only fit into its receptor site
Cause organs to respond in their presence
Removed from body through kidneys

Hormone
Testosterone

Endocrine gland
that produces it
Testes

Target cells/effect
Many organs

Thyroxine

Thyroid

Heart muscle

Growth hormone

Pituitary gland

Bone and liver

Adrenaline

Adrenal gland

Insulin

Pancreas

Many organs – liver
and muscle
Liver and muscle

Oestrogen

Ovaries

Ovaries, pituitary
glands and uterus

FSH

Pituitary glands

egg follicles

LH

Pituitary glands

Mature egg follicles

Glucagon

Pancreas

liver

Effect
Controls and
provokes puberty in
males
Increases cell`s
respiration
Increases growth rate
of tissue
Prepares body for
action, “fight or flight”
Controls blood sugar
levels
Controls puberty and
menstrual cycle in
females, stimulates
production of LH and
lowers FSH
Provokes growth and
maturation
Triggers egg release
and ovulation
Break down of
glucagon and release
into blood, controls
blood glucose levels

14
...
17 – CB7B HORMONAL CONTROL OF METABOLIC RATE
METABOLISM – describes all chemical processes that go on continuously inside the body to
keep you alive and your organs functioning properly (breathing, digestion and respiration)
BASAL/RESTING METABOLISTIC RATE – minimum amount of energy required for processes
THYROXINE –




Produced in thyroid glands
Main hormone secreted into bloodstream
Helps for digestion, heart and muscle function, brain development and maintenance of
bones, controls metabolic rate and acts as a form of negative feedback

Thyrotoxicosis (too much) –









Swelling of the neck
Intolerance to heat
Weight loss
Increased appetite
Increased bowl movements
Irregular menstrual cycle
Rapid/irregular heart beat
Palpitations, tiredness, irritability and staring appearance

Hypothyroidism (too little) –






During development of birth – mental impairment and reduction of physical growth
Decreased metabolic rate, reduced appetite
Fatigue and depression
Intolerance of cold temperatures
Low heart rate, stiffness of muscles, poor memory and infertility

18
...
17 – CONTINUATION
NEGATVIE FEEDBACK – a control mechanism that reacts to a change in condition, such as
temperature, by trying to bring the condition back to a normal level



If levels are too high – hypothalamus produces TRH which targets pituitary gland,
stimulating release of TSH which lowers production of thyroxine at the thyroid gland
and vice versa
...
9
...

Cervical caps – Small cap that fits over cervix, prevents sperm fusing egg

HORMONAL BARRIERS – use of hormones to stop or ovulation and prevent pregnancy





Injectable birth control - involves injection of a progestin which thickens uterus lining so
sperm can`t pass through
Combined oral contraceptives – pill consisting of both progestin and oestrogen causing
lining to thicken
Contraceptive patch – patch that releases hormones into skin
Vaginal ring – ring inserted into vagina which releases delivers a estradiol and progestin
for around three weeks

20
...
27 – BLOOD GLUCOSE
HOMROSTASIS – the maintenance of a consistent environment in the body by constant feedback


The body is consistently ensuring chemicals and conditions are where they should be

Average glucose levels –
NORMAL – 90 mg/cm3
AFTER A MEAL – 130 mg/cm3 (more glucose consumed within food)
AFTER VIGEROUS EXERCISE – 60 mg/cm3 (glucose lost during aerobic respiration)



If blood sugar levels are too high, pancreas releases insulin (hormone) which sends a
message to the liver to convert glucose into glycogen (stored in liver and muscles)
If blood sugar levels are too low, pancreas releases glucagon (hormone) which sends
message to liver to convert glycogen into glucose

28
...
17 – CB7D HORMONES AND THE MENSTRAL CYCLE

1
...
LUTEINISING HORMONE (LH) AND FOLICLE STIMULATING HORMONE (FSH) – pituitary
gland
CONTROL OF HORMONES IN THE MENSTRAL CYCLE 1
...
This stimulates egg follicle to grow and develop
2
...
High levels of oestrogen results in the pituitary gland releasing LH and this
stimulates egg release (ovulation)
4
...
Increasing levels of progesterone inhibits FSH
and LH products
...
If the egg cell isn’t fertilised, levels of oestrogen and progesterone drop
...
Low progesterone and oestrogen levels allows an increase in FSH levels and cycle
beings again

ASSISTIVE REPRODUCTIVE TECHNOLOHY (ART) – technology that helps to increase the chance
of pregnancy, such as hormones to stimulate egg release
1
...
Clomiphene therapy – drug given to women which increases concentration of FSH and
LH in the blood (caused by egg follicles not being matured and released)
2
...
17 – CB7F TYPE 1 AND 2 DIABETES
DIABETES – a disease in which the body’s ability to produce or respond to insulin is impaired



Insulin is injected into a fatty layer between the skin and muscles (subcutaneously) to
prevent it being used up to quickly
Area injected into should vary to prevent breaking down and building up of fat
(lipodystrophy) causing indents and lumps – bottom, abdomen…

TYPE 1 – caused by the immune system attacking itself (autoimmune disease), meaning
pancreas no longer produces insulin
-

Pump required that is attached to body via a cannula, BM tracker used every couple of
hours to check glucose levels (6-8 being normal)
turned up high to increase insulin if glucose levels too high
If too low, Lucozade or sugar items consumed to bring up glucose levels

TYPE 2 – caused by the body being resistant to insulin and therefore stops responding to it
-

Most likely to affect those over 40
Required to modify diet and exercise more
Risk factors include weight, high blood pressure and genetics

BMI – body mass index, weight (kg) /height (m)2
WAIST: HIP RATIO – ratio of waist in proportion to hit to measure amount of fat, w/h
-

The higher the BMI or hip ratio, the greater chance of getting type 2 due to obesity being
a risk factor

4
...
18 – CB8A EFFICIENT TRANSPORT AND EXCHANGE
UNICELLULAR – organism only consisting of one cell (bacteria + ambia)
MULTICELLULAR – organism with multiple cells (humans, animals, plants)
Unicellular

by diffusion

Oxygen
Multicellular





Respiration/
transport system
Veins, arteries, capillaries all needed within human transport system
Also consists of a pump (heart), to increase efficiency further
Xylem and phloem cells used in plants transport system

EXCRETION – the removal of metabolic waste (unwanted products of cell metabolism) from the
body, i
...
Thin, don’t need to diffuse far
2
...
1
...


VALVES – restrict blood flow from going in wrong direction, found in veins due to low pressure
(deoxygenated blood) to prevent falling back down

Blood –

-

For every mm3 of blood
5,000,000 red blood cells (erythrocytes)
7,000 white blood cells
250,000 platelets

CAPILLARIES - type of vessel, connecting veins and arteries, feeding all body cells by an
exchange of substances between blood and tissues
PLATELETES – tiny fragments of cells that have no nucleus and produce substances needed to
clot the blood at sit of an injury, ensures no infection by forming mesh before scab
PLASMA – straw/pale coloured liquid suspending cells in blood, also carrying dissolved
substances (carries everything besides oxygen - glucose, urea and co2) – 55% of blood, cells
other 45%
HAEMOGLOBIN – substance in red blood cells that bonds with oxygen in lungs and releases it in
tissue (lack of this causes anaemia, lack of iron)
Red blood cells DARK RED BLOOD CELLS – little haemoglobin (deoxygenated)
BRIGHT RED BLOOD CELLS - a lot of haemoglobin (oxygenated)




No nucleus – more space for haemoglobin
Biconcave shape (discs with dimples) – large SA:V ratio for oxygen to diffuse in and out
Small and flexible – to fit through narrow blood vessels

WHITE BLOOD CELLS – remove foreign cells that get inside the body (pathogens) and work
within immune system

1
...
LYMPHOCYTES – antibodies which stick to foreign cells and help destroy them
15
...
18 – CB8C THE HEART
HEART ATTACK – blood stops flowing to the muscles in part of the heart, damaging the heart
and stopping it from working properly (if heart stops completely, use of a defibrillator to force
electric shocks though it)
CHAMBERS – areas in heart that prevent oxygen-depleted blood from mixing with oxygen-rich
blood (different sectors)
VENA CAVA – large vein passing blood into right atrium
PULMONARY VEIN – pass oxygenated blood from lungs to left atrium (from lungs back to
heart)

PULMONARY ARTERY - transports de-oxygenated blood to the lungs coming from the right
ventricles
CONTRACT – movement of becoming shorter and tighter in relation to one another
VENTRICLES – chamber of heart which receives blood from the top two chambers, contracts
and “pumps blood out of heart” into arteries
HEART VALVES –valves used to restrict blood flow to ensure it only travels in correct direction
SEPTUM – wall/partition separates two sides of the heart
TENDONS – cord connecting two valves, preventing them from turning inside out
AORTA – main artery supplying oxygenated blood to rest of body
DEOXYGENATED BLOOD – blood with a low saturation of o2, oxygen used up and carried
through veins back to heart
OXYGENATED BLOOD – blood with a high saturation of o2 , a lot of oxygen to pass round body
and carried out through arteries
IMPULSE – electrical signal transmitted along a neuron, controlling the contraction and
relaxation of muscles during each heartbeat
HEART RATE – number of times the heart beats per minute

STROKE VOLUME – volume of blood pushed into the aorta in each beat, measured in litres
CARDIAC OUTPUT – volume of blood pushed into the aorta each minute
= Heart rate x stroke volume

BLOOD PRESSURE – pressure of blood pushing against walls of larger arteries (mmHg –
millimetres of mercury) – “120/70 “
DIASTOLE – (lower number of blood pressure) pressure when ventricles relax in arteries and
heart refills with blood
-

Blood flows into upper heart chambers which then contracts, pushing it into lower
chambers

SYSTOLE – (higher number of blood pressure) pressure when ventricles contract and push
blood out of heart
-

Lower chambers contract, pushing blood out of heart

Route of blood through the body –





Deoxygenated blood enters heart through the vena cava, into the right atrium
Drains from tricuspid valve into right ventricle (close to prevent blood flowing back
up intro atrium)
As it contracts, deoxygenated blood passes through semilunar valve into pulmonary
artery
Blood carried to lungs where it becomes oxygenated



Oxygenated blood returns via pulmonary veins, entering left atrium



When relaxed, blood drains into left ventricle through the left bicuspid valve



Muscles squeeze, causing left ventricle to contract and blood passes aortic semilunar
valves into aorta



Aorta branches out into more and more arteries at a high pressure to travel around the
body



Arteries meet with capillaries where oxygen is exchanged for carbon dioxide



Capillary exchange occurs whereby oxygen and other nutrients is delivered to cells,
where then waste products are expelled (co2)



Capillaries carry waste products in the deoxygenated blood (oxygen taken in by cell)
into venuels – branch off into veins



Veins then carry deoxygenated blood back to vena cava, entering right atrium where
process begins again

-

Wall of left ventricle thicker than right

-

Right ventricle – lungs (thinner)

-

Left ventricle - entire body (thicker)

-

Thicker wall to contract to produce enough force to push blood around entire body



25
...
18 – CB8D CELLULAR RESPIRATION

CELLULAR RESPIRATION – series of chemical reactions occurring in all living cells in which
glucose is broken down to release energy (exothermic reaction)
-

To move, thermoregulation and Digestion/synthesis



Glucose – taken in as food, produced in small intestine, carried in plasma



Oxygen – taken in through the air, gas exchange in alveoli in lungs, carried in
erythrocytes



Co2 and water – useless waste products



Energy – useful product
Effect of exercise

How this helps the body

Breathing rate increases and becomes deeper

To increase the oxygen uptake in the lungs to
supply muscles, co2 also exhaled more quickly

Heat beat faster

Heart rate and stroke volume increase so
cardiac output also increases, delivers more
blood (containing oxygen and glucose) to
respiring cells

Reduced blood flow to capillaries in liver but
increased flow to muscles

To replace the oxygen being used up quickly
during strenuous exercise at a faster rate than
usual

Skin turns red and sweat is released

Muscles produce heat when working hard and
radiate this from surface of skin
...
1
...
Independent variable (what was changed) – temperature
2
...
Control variable – number of organisms, greater number of organisms, greater rate of
respiration/co2 produced
4
...
Gas used up by organisms – o2
6
...
2
...
s
habitat includes other organisms that affect the population and environment

Measuring population 



Measuring population size by counting all the organisms is impossible
Instead, can be estimated by taking samples using a quadrant
Placed randomly in the area, and number per each quadrant is counted to gain a more
accurate result

FOOD WEB – shows the feeding relationships between organisms in a community
PRODUCER – organisms which produce their own food using light energy from the sun, co2, o2
and water (plants)
PRIMARY CONSUMER/HERBIVORE – organisms that feed directly off of producers for food, only
eats plants
SECONDARY CONSUMER– organisms that feed off of other consumers, eat other animals
CARNIVORE – organisms that only eat other animals for food
OMNIVORE – organisms that eat both other plants and animals
TERTIARY CONSUMER – high level consumer, often the top predator of ecosystem/food chain
HETEROTROPHIC – organisms which use organic substrates to get their energy, carbon and
nutrients for growth and development
DECOMPOSERS – organisms which break down dead or decaying organisms, and whilst doing
so, perform decomposition
20
...
18 – CB9B/C BIOTIC AND ABIOTIC FACTORS

ABIOTIC – non-living conditions that can influence where plants/animals live and their
ecosystems – temperature, amount of light, concentration of co2 e
...
t (can also be unnatural –
acid rain, pollution)
BIOTIC - living components (organisms) in an ecosystem, whereby within a community, can
affect other organisms
-

Competition for food
Competition for shelter
Predator and prey cycles
Spreading of disease

INTERSPECIES – competition between different species
INTRASPECIES – competition between the same species
Predator-Prey cycle:

As amount of prey increase, more food for
predators, number of predators increase, prey
then decrease, predators decrease, prey
increase e
...
t
...
2
...
3
...
2
...
2
...

2
...

4
...

6
...

8
...

10
...
Snow or slate
Flow back into river/lakes, towards ocean again
Also reaches oceans through rocks and soil as groundwater
Cycle repeats

Water in our bodies 










60% of our bodies consist of water, as well as being a significant part of a cell`s
cytoplasm where reactions occur
extremely important for survival
Taken in through eating and drinking
Given out during urination and transpiration
Plenty of water from various bodies (lakes, rivers, ponds) for washing
Must be treated with chemicals and filtered to make potable
Can also be filtered, removing non-toxic substances to improve taste
Places of drought collect water from air or extract from sea water
Desalination used – distillation and other methods used within this
Can also be achieved through: retrieval, sedimentation, filtration and chlorination

7
...
18 – CB9H THE CARBON CYCLE
FAECES – undigested food that forms waste material
BIOMASS – total mass in living organism, usually shown after dying
DECAY – process whereby complex substances in animals and plants are broken down by
decomposers into simpler substances
DECOMPOSERS – an organism that feeds off of dead matter, causing decay (bacteria)
FOSSIL FUELS – fuels formed from dead remains of organisms over millions of years
CARBON CYCLE – sequence of processes by which carbon moves from the atmosphere, through
living and dead organisms, into sediments and the atmosphere again
CARBON SINK – natural or artificial reservoir that accumulates and collects carbon as a matter
of sequestration (oceans, soil, plants)







Every cell contains carbon
4th most abundant element in the universe
Plants take in carbon monoxide from the atmosphere for photosynthesis and transform
into sugars/glucose for energy
Respiration and combustion release carbon monoxide back into atmosphere
All processes balance each other out and form an equilibrium, maintaining a stable cycle
of carbon

Importance of carbon –






Proteins, sugars and fats all contain carbon
Present in atmosphere as co2
Carbon within plants are consumed by animals, passed along food chain and consumed,
then released back out
As dead matter decomposes, also released back into atmosphere, and some into soil
Can also form fossil fuels and sedimentary rock (limestone) which are long term stores

Carbon cycle 1
...

3
...

5
...

7
...

9
...
3

---