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Recognise cell structures as seen with a light microscope and with an electron microscope
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Nucleus – Controls cell activity
Cytoplasm – jelly-like substance where chemical reactions take place
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Respiration releases energy that the cell needs to work
Endoplasmic reticulum - Provides mechanical support to the cell
...
It acts as an intracellular transport system
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A-T
G-C
DNA is made up of two strands of mononucleotides running opposite directions (antiparallel)
Understand the multiplication of cells with a simple outline description of the four
stages of mitosis
...
Understand that mitosis occurs
during growth, repair, cloning and asexual reproduction
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Mitosis is for growth and repair
...
They continue this process with 4 stages prophase (chromosomes condense this
means they thicken & become visible with a light microscope), Metaphase – micro tubules
grow from the centrioles and attach to the centromeres
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Cytokinesis begins
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Mitosis occurs during the cell replacement
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Different cells form tissues
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Involuntary muscle when your brain doesn’t control these things
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Cardiac – heart muscle
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Blood – tissue made of different types of red &
white blood cells within plasma
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Epithelium – hair-like projections called cilia
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Inside of
lining of human cheek is an example of squamous and ciliated
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Recall the organisation of cells into organs
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Carbohydrates, lipids (fats & oils) all have carbon, hydrogen and oxygen in them
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Understand the structure of carbohydrates, proteins and lipids as large molecules
made up from smaller basic units: starch and glycogen from simple sugars; protein
from amino acids; lipid from fatty acids and glycerol
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The simple sugars produce a rapid increase in blood sugar for short-term energy
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Starch is found in plants and
glycogen is found in animals
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Amino acids are made
from protein
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Describe the tests for glucose, starch, lipid and protein
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Green precipitate (cloudy
layer on top of solution) means glucose is present in small amounts
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Bluish colour means that there is no glucose
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Starch: Add a few drops of iodine to sample and if the same goes blue/black then starch is
present
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If sample goes blue, that means there is no protein
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2) Use sudan dye and dye the solution and if it turns red/orange it means lipid is
present
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Explain the role of enzymes as biological catalysts in metabolic reactions
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This is done by the
enzymes lowering the activation energy in the reaction
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Also, the catalysts don’t undergo change during reaction
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If the temperature is too high, the enzymes will denature
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Rate of reaction will be
slower in too cold temperatures
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pH is similar, at a low pH, the enzyme activity is low and at a high pH, the
enzyme activity is also low
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7 and this is where enzyme activity is
highest
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Example: in the stomach the optimum pH for enzyme is 2
because of the HCL
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5
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1) Put starch in test tube and do it at different temperatures and add amylase to test
tube
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Time how long it takes
for iodine to stop being blue/black
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When iodine stops being blue/black, there is no more starch
present
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At low temperature, it would take
longer for iodine to be blue/black
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Recall simple definitions of diffusion, osmosis and active transport
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Osmosis – The movement of water from a dilute solution to a concentrated solution
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Understand that movement of substances into and out of cells can be by diffusion,
osmosis and active transport
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Osmosis- When water diffuses into a plant cell, it makes the cell turgid (straight)
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For
example: magnesium or chlorophyll
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You need energy to push the molecules by ATP
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Rate of movement is affected by surface area to volume ratio
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Temperature increases the
kinetic energy of the particles so that the diffusion occurs quicker
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Describe how to carry out simple experiments on diffusion and osmosis using living
and non-living systems
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Higher the temperature, the more
kinetic energy, therefore the colour is moving faster throughout the liquid
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Put one piece in
distilled water and the other in salt water
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The one in salt water would have lost mass as the water in the potato
moves to the more highly concentrated salt water
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Osmosis takes place in all cells; the cell
membrane is partially permeable (allows water to go to other side)
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Axial skeleton contains the vertebral column, ribcage and skull
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Appendicular skeleton contains the scapula, clavicle, pelvis and limbs
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It’s unfused (not linked
together) this allows for a greater range of motion
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Long bone – elongated bone consisting of a body (diaphysis) and two terminal parts
(epiphyses), such as the leg and arm bones (femur, radius and phalanges)
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The appendicular skeleton, which is attached to the axial skeleton, is formed by the
pectoral girdle, the pelvic girdle and the bones of the upper and lower limbs
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Explain the functions of joints using the elbow, shoulder and a cartilaginous
intervertebral joint as examples
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The elbow is a synovial joint
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Shoulder – also has diarthroses joint
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Cartilaginous intervertebral joint – located in the vertebrate

Describe the structure of a synovial joint
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The ends of the joint bones are covered with a smooth,
articular cartilage (reducing friction during movement)
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It acts
as a shock absorber, and allows friction free movement
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Voluntary muscles – Consist of triceps and biceps
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One flexes whilst one extends
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This is the same with
the quadriceps and hamstrings
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Recall the dietary factors controlling the healthy development of muscle and bone
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Low calcium leads to a lower bone density, leading to an increase risk
of fractures
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The use of tobacco and high alcohol consumption leads to
weak muscles and bones
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Recall the structure of neurones: sensory, motor and relay
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(Search up
comparisons of Google)
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Central nervous system contains the brain and spinal cord
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Signals
travel along the axons causing neurotransmitters to be released at synapses
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Neurones send neurones through axons
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The electrical impulse can
only travel in one direction
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There is a small gap between the two neurones at a synapse called synaptic
cleft
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This diffuses across the cleft and attaches to dedicated sites on the cell membrane of
second neurone
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Recall the structure and functions of the spinal cord
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The spinal nerves carry
sensory nerve impulses towards the spinal cord and brain
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The grey matter contains nerve cell
bodies and dendrites
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lesson 12 page 8
Describe the structure of the reflex arc
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The
relay neurone is not involved because it’s involuntary
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Two types of reflexes which are autonomic (affects inner organs) and somatic (affects
muscles)
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Recall spinal reflexes, including the knee jerk and withdrawal reflex
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"
Most reflexes called spinal reflexes involve spinal nerves and the spinal cord, not the
brain at all
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This
helps maintain posture and balance allowing them to keep balanced without
conscience thought)
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g
...
g
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Recall the main areas of the brain and their functions in outline, including the
cerebral hemispheres, cerebellum, mid brain, pituitary gland and hypothalamus
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There are receptors in our skin which respond to heat
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Mechano receptors respond to mechanical
stimuli
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Understand the integrated action of hormones from the pituitary (ADH and
gonadotrophic hormones), adrenal (adrenaline) and thyroid glands, the islets of
Langerhans in the pancreas (insulin and glucagon) and the gonads and recall the
role of hormones in growth and development
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Hormones are chemical messengers
that go directly in your blood stream they regulate your body’s activities and the
chemistry
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It also controls growth, urine production, blood chemistry and
reproductive activities
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e
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ADH (Anti-diuretic hormone) lesson 11 page 12 is responsible for affecting blood
pressure
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The islets of Langerhans are secreted directly into the blood
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Insulin regulates blood glucose by allowing many of the
body cell to absorb and use glucose, this drops the blood glucose level and glucagon
does the opposite
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Problems in the regulation of the pancreas hormones will cause blood sugar
imbalance)
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Nervous system
 Works by nerve impulses
transmitted through nerve cells
(although chemicals are used at

Endocrine system
 Works by hormones transmitted
through the bloodstream





synapses)
Nerve impulses travel fast and
usually have an ‘instant’ effect
Response is usually short-lived
Impulses act on individual cells
such as muscle fibres, so have a
very localised effect





Hormones travel more slowly and
general take longer to act
Response is usually longer-lasting
Hormones can have widespread
effects on the different organs
(although they only act on
particular tissue or organs if the
cells have the correct receptors)

The nervous system and endocrine system both use chemical messengers to signal
cells, but the speed of transmission is different
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Insulin/ glucagon  negative feedback (changes from stimulus in environment cause
fluctuations in the hormones)
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Temperature control – if our body is feeling too hot, the body will lose heat by
sweating and if our body temperature is slow, then our body will increase out
metabolic action by shivering (in animals by thickening the fur)
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m) The ear: recall the structure of the ear and describe its functions in
balance and hearing
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It has light receptor cells in the retina
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When there is increased light, your pupil shrinks
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This happens because the iris contracts to make the pupil smaller, or it
relaxes to make it bigger
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In
increased light, the radial is relaxing and the circular in contracting; in this way less light
in entering
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The eye is adapting its shape
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If an object is far, the ciliary
muscles will relax, making the suspensory ligaments contract so that they pull the lenses
to make them thin
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Stereoscopic vision – if you have two eyes working together you can see 3D vision
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The ear catches sound waves and converts them into impulses that the brain interprets
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The outer ear leads down the auditory canal
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The semi-circular canal helps in balancing
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Describe a balanced diet: including carbohydrates, proteins, lipids, vitamins, minerals,
water and dietary fibre
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Understand variations in diet related to age, pregnancy, climate and occupation
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Older people are
less active therefore they don’t need that much energy
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In areas where there’s high
temperature, they would need to consume more energy as they sweat a lot
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Recall the sources and functions of carbohydrates, proteins, lipids (fats and oils),
vitamins A, C and D, and the mineral ions calcium and iron
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Prevents anaemia (blackcurrant, grapefruit, orange)
Vitamin D – Helps immune function and for muscle strength
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(Salmon, mackerel, cheese, eggs)
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(Milk, cheese, yogurt) Iron: is important for transporting oxygen to
tissues and it’s a component of myoglobin
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Having too
little haemoglobin is called anaemia
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Understand that energy requirements vary with activity levels, age and pregnancy
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Older people are
less active therefore they don’t need that much energy
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In areas where there’s high
temperature, they would need to consume more energy as they sweat a lot
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Skin, muscles and organs all contain protein
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This will cause your muscles to shrink; your
immune system will be less strong and you’ll be more vulnerable (higher risk of being
infected by cold/flu) due to protein deficiency meaning higher infections
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Recognise the structures of the human alimentary canal and describe in outline the
functions of the mouth, oesophagus, stomach, small intestine, large intestine, and
pancreas
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Oesophagus is the tube that connects the mouth to the stomach so the food goes
down the oesophagus and there is a process called peristalsis
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The churning in the stomach mechanically
digests the food, while enzymes digest the food chemically
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In addition, the villi cover the inside of the
small intestine to give it a large SA so that more molecules can diffuse into the blood
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The pancreas
produces the enzymes amylase, lipase and protease
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Dietary fibre keeps the bowels functioning well
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Understand the role of digestive enzymes to include the digestion of starch to glucose
by amylase and maltase, the digestion of proteins to amino acids by proteases (pepsin,
trypsin) and the digestion of lipids to fatty acids and glycerol by lipases
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Amylase converts starch
maltose and the enzyme maltase converts maltose to glucose
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The enzyme pepsin is found in the stomach and
trypsin (pH level is 2-3 because stomach is acidic) is found in the small intestine
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The pancreas secretes juices into the
small intestine which includes lipase
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Food is acidic after being in the stomach and bile is alkaline so it can neutralise the
stomach acid that’s surpassing the liver
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Bile emulsifies fats, which gives them a larger surface area, making it easier for the
lipases to work
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The villi on the lining in the small intestine have very thin walls which enables the
molecules to pass through easily
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They also increase the surface area of the small intestine wall,
increasing the rate of diffusion
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The capillaries allow transport of nutrients to the live
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Understand the factors which affect
their growth
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The job of the teeth is to cut, tear and grind food
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* Incisors act as a blade to cut food, they are quite sharp
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Premolars are used to cut and grind food
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-Tooth decay is when bacteria in our mouth feed on the bits of food
leftover
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Reduce sugar intake to prevent the bacteria respiring brush

teeth regularly to remove plaque which is layer of bacteria
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Describe how to carry out a simple experiment to determine the energy content in a
food sample
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Then, record the mass of water and record mass of food
sample
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Hold it at the base of the test tube and when
the food is fully burnt, record the temp of water
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Energy (joules) = mass of water x change in temp x 4
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All of this over the mass of the food sample
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Digestive enzymes work in the body so you know they work best around body
temperature so if doing a design then put all the tubes in a water bath at
around 37 degrees
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Know where in the digestive system the enzyme is
normally found so pepsin is in stomach so works best at an acid pH
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Make sure
you know the end products of what the enzyme breaks down i
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amylase are
glucose, protease is amino acids, and lipase is fatty acids and glycerol
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Record the time it takes
for substrate to be completely broken down
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Compare the times to work out the optimum temperature of the enzyme, use same
enzyme, to make this a fair test
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The
only different thing is the temperature
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Respiration breaks down glucose to release energy
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The energy is used for processes such as cell division, muscular
contractions and active transport
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Aerobic uses oxygen and anaerobic is without oxygen
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Aerobic respiration releases
more energy, but takes longer to release its energy than anaerobic
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This high concentration of lactic acid causes muscular
pains and cramps
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Glucose + Oxygen  Carbon Dioxide + Water (+energy) – in the form of ATP
C6H12O6 + 6O2  6CO2 + 6H2O (+ ATP)

Describe how to carry out simple controlled experiments to demonstrate the evolution
of carbon dioxide in respiration
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ATP can be released as heat energy or can be used as a power source to drive different
type of chemical reactions
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This reaction uses an
enzyme using ATPase
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This is obtained
in the process of oxidation
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In anaerobic respiration, not enough oxygen is reaching the muscles
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Glucose forms lactic
acid and a small amount of energy
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The lactic acid is removed from the muscles by
blood flowing through them
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Recall the structure of the thorax, including the ribs, intercostal muscles, diaphragm,
trachea, bronchi, bronchioles, alveoli and pleural membranes
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When you breathe in, the intercostal muscles contract
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The trachea carries the air towards the lungs; this
is taken to the bronchioles which end at alveoli where gas exchange takes place
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All of this reduces the space inside the lungs, pushing the air
out
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The alveoli have think walls which allows gases to diffuse through them easily
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There is a lot of

surface in contact with the bloodstream for the gases to diffuse into
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Explain the term lung capacity, including vital capacity, tidal volume and explain
spirometer traces of breathing movement
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Vital capacity is the maximal amount of air a person can expel from the lungs
after a maximum inhalation
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Spirometer records breathing and respiration
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Vital capacity – the most he can breathe
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Chemoreceptors (receptors in the skin) detect the levels of carbon dioxide in the blood by
monitoring the concentrations of hydrogen ions in the blood
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If there’s a decrease in the
blood pH, the respiratory centre (detects this) sends nervous impulses to the external
intercostal muscles and the diaphragm to increase the breathing rate and the volume of
the lungs during inhalation
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Understand the biological consequences of smoking in relation to the lungs and the
circulatory system
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Smoke removes the cilia
which keeps the lungs clean
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Describe how to carry out simple experiments to investigate the effect of exercise on
breathing in humans, including the use of limewater or bicarbonate indictor
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People who are more active are more likely to live longer and are less likely to develop
serious diseases such as diabetes and heart disease
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Exercise can reduce
the risk of heart disease and stroke
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It can help improve your mental and wellbeing
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Recall the composition of the blood: red blood cells (erythrocytes), white blood cells
(phagocytes and lymphocytes), platelets and plasma
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The blood cells are known as rocytes
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Plasma is largely composed of water
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Explain the effects of genetically inherited conditions such as sickle cell anaemia
(autosomal inheritance) and haemophilia (sex-linked inheritance)
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It causes the entire blood cell
to change shape under stress conditions and because of this, they cannot squeeze through
the small blood vessels
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This can damage tissues and vital
organs
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The inheritance depends on the presence or absence of
certain alleles and autosomes
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This results in excessive bleeding which is often
internal
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Therefore, it occurs more in males
than in females
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Water which is the main component of plasma is a solvent and a liquid
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Water also carries the
energy which is important in the regulation of body temperature
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Red blood cells carry oxygen around the body
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Red blood cells have no nucleus to make room for the haemoglobin
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Red blood cells are biconcave (flat disk with a dip in the middle)
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The dip in the
middle is to increase the SA and decrease the distance for diffusion, meaning that
diffusion of oxygen happens quickly
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White blood cells have phagocytes and lymphocytes
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The white blood cell produces B cells and T cells (lymphocytes)
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The B cells produce antibodies
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Macrophage (same as phagocytes)

ingests bacteria
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Lymphocytes stay in the lymph system
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When you get hurt, you lose blood
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The
chemicals in platelets turn fibrigen into a solid called fibro
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The tissue beneath this can begin to repair the
damaged womb
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Understand the role of ABO blood groups and their importance in blood transfusions
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The blood groups are determined by the types of antigens
you inherit from your mum and dad
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Type O is when
neither antigen are present
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Understand the problems associated with transplants, including the need to avoid
rejection
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The
immune system would not be familiar with the foreign antigens and would create
antibodies to keep the foreign cells away
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The immune system will try to destroy the new organ so antirejection medicines will need to be taken
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Recall the structure of the heart and how it functions
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The atria’s contract first and the ventricles
contract second
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When the ventricles are full, they
begin to contract
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Blood is forced out of the heart
into the circulatory system through the open semi-lunar
valves, and when the ventricles finish contracting, the
semi-lunar valves shut which stops back flow of blood
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The left side of heart is bigger than right side
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CHD is the main cause of heart attacks
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During a heart attack, a plaque bursts, causing a
blood clot
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Also, heart attacks are caused by people who smoke and by people who have
a lot of high cholesterol in their diet and have high blood pressure, who are overweight or
obese and people who do less exercise and who drink a lot of alcohol
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Atherosclerosis also causes heart attacks
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During exercise, muscles require more energy which is created by respiration
...
This means that the heart
needs to work harder & increase its speed so that more blood is sent to the muscle
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If someone is under the influence of adrenaline, it
stimulates receptors in the heart which increase the heart rate
...
Also, the body prepares itself for the ‘fight
or flight’ response
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Recall the structure of arteries, veins and capillaries and understand their roles,
including the pulse
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The blood inside the arteries is under high
pressure, they deliver blood to an organ
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The veins now take blood to the heart to refill it with oxygen
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There are valves
in the veins which prevents the blood flowing in the wrong direction
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Capillaries are where gas exchange takes place
...
The pulse is a measure of speed at
which the heart is pumping blood around the body
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Tissue fluid is a thin layer of fluid that surrounds the body cells
...
It also acts as a medium (or platform) for sending chemical messages across
cells
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Exchange of tissue fluid,
gasses and nutrients takes place in the capillaries
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The veins take blood to the heart
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Blood leaves the right ventricle and enters the lungs through the pulmonary artery
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Blood leaves aorta through left
ventricle
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Blood
returns to heart through the vena cava
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Vein- to the heart
Artery- away from heart
Lung- pulmonary
Liver- hepatic
Kidney- renal
Stomach- gastric
between the gut and liver is the hepatic portal vein
...
All living
things have receptors so they are able to detect change and there are effectors that are
able to carry out fast response
...
An example would be
osmoregulation which is control of water levels in the body
...
An example is when the body is too hot it sweats and when the
body is cold the hairs on your arms stick up, which traps air as a layer on insulation
...

The body needs to stay at 37
...
The body’s temperature is monitored by the brain
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If it’s too cold, the hair on your skin will stand up so that they trap warm
air as a layer of insulin
...
Blood vessels can
shrink so they constrict and this reduces heat loss – this is called vasoconstriction
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Also, the blood vessels dilate, causing more heat to be carried
by the blood to the skin
...
When you’re
cold, the muscles shiver which warms you up
...
Another function of the
skin is that it prevents loss of moisture, helps regulate temperature and acts as a sensory
organ
...

Recall the definition of excretion; the removal of metabolic waste, including urea,
carbon dioxide and water
...
Metabolism is all the chemical reactions that
take place in a cell/organ/organism
...
Urea is made in the liver from the breakdown of worn out
red blood cells and is released in the urine by the kidneys
...
Excretion is important because it
prevents toxic build up in our body
...

The renal system is the urinary system
...
The formation of urine is important because it helps
the body get rid of metabolic waste and toxins
...
Nephrons are in the kidney and they filter the blood and cause waste to be
removed (they’re really small)
...
Fluids containing excess water, salt and metabolic waste products are
extracted from the blood as they enter the Bowman’s capsule
...
1) Glomerular filtration (this is where water and other substances pass
into the Bowman’s capsule) – this process must be controlled precisely
...
2) Tubular reabsorption and secretion
...
The glomerular filtrate enters the renal tubule (the tubule is very long so it
increases the SA)
...
When water is being reabsorbed, this is an important process (and it’s
regulated by hormones) because the more hydrated a person is the less water is
reabsorbed
...
3)
Water conservation
...
But if too much water is removed, it results in
dehydration, leading to serious health conditions
...

Recall that the lungs, kidneys and skin are organs of excretion
The waste product in the lungs is CO2
...

They diffuse into the kidneys
...

Recall that the kidney carries out the roles of excretion and osmoregulation
Amino acids contain nitrogen which is toxic to the body
...
In osmoregulation, kidneys respond to the ADH hormone and this is
released by the pituitary gland
...
If there is too little water, ADH is released and the kidneys won’t absorb
any more water
...

Recall the structure of the urinary system including the kidneys, ureters, bladder and
urethra
GOOGLE PICTURE

Recall the structure of a nephron to include Bowman’s capsule, glomerulus,
convoluted tubules, loop of Henlé and collecting duct
...

GOOGLE PICTURE
...

The blood enters the Bowman’s capsule, and it travels to the glomerulus under higher
pressure as the tubes are smaller
...
(This is a glomerulus filtrate)
...
The loop oh Henley
is where water and sodium chloride are reabsorbed into the bloodstream
...

Water is reabsorbed into the blood from the collecting duct
...
So the first section of convoluted
tubules is the proximal convoluted tubal
...

Describe the role of ADH in regulation the water content of the blood
Excess or lack of water is detected by the hypothalamus in the brain
...
This hormones travels through the
blood steam to the kidneys
...
The urine is then concentrated with a lower volume
...

Recall that urine contains water, urea and salts
...

Describe the value of kidney transplants and understand the problems of tissue
matching to avoid rejection and the role of artificial kidneys such as dialysis machine
...
The
tissues of the kidneys must be of the same type otherwise the body will reject the tissue
and cause serious health conditions
...
The blood travels through the tube into a dialyzer which filters out extra
salt and extra water
...
This is repeated to keep the blood clean
...


Explain the importance of rehydration following loss of body fluids through vomiting
and diarrhoea
Dehydration occurs when your body loses more fluid than you take in
...
If you’re not
drinking enough fluid/ fluid that is lost isn’t replaced, or you have vomited or have
diarrhoea, this causes dehydration
...
You can rehydrate by drinking lots of water
...

Describe the oral rehydration method
There’s an oral rehydration solution, this treats dehydration caused by diarrhoea
...
This should be taken after very meal, or as
much as needed
...
The main
function of the liver is the secretion of bile
...
When blood glucose is low, the liver breaks down stored glycogen into glucose and
released it into the bloodstream
...
When blood glucose is high, the liver converts the glucose into glycogen for
storage
...

The liver detoxifies substances such as alcohol
...

Describe the effects of excess alcohol on the liver, nervous system and behaviour
On the liver, excessive consumption of alcohol can cause strain of the liver and cause liver
cancer and it cirrhosis on the nervous system
...
It can also make the person very angry, anxious and it gives
them a slow response rate
...

Recall that the process of fertilisation involves the fusion of a male and female gamete
to produce a zygote
Gametes are sex cells
...
As the zygote divides repeatedly, it becomes an embryo
...
These gametes
undergo fertilisation which restores the diploid number of chromosomes (meiosis reduces
the chromosome number by half)
...
2) Independent assortment of homologous pairs
...
4 stages: prophase – chromosomes
condense centrioles form and move towards the poles
...

Metaphase – micro tubules grow from the centrioles and attach to the centromeres
...
Cytokinesis
begins
...
Cytokinesis completes, creating
two haploid (half chromosomes) daughter cells
...
For the male reproductive system, the testies produce sperm cells
...
The urethra carries sperm to the
end of the penis
...
The
oviduct carries the eggs to the uterus and the uterus develops the fertilised egg and the
cervix is the entrance to the uterus
...
It does two things: stop FSH being produced so that
only one egg matures in the cycle and it also stimulates the pituitary gland to release LH
...
FSH is secreted by the pituitary
gland
...
LH causes the mature egg to be released from the ovary
...

Understand the formation of a zygote from an ovum and its development into an
embryo involving cell division
The process of an embryo forming and developing is called embryogenesis
...
Once fertilised, the ovum is called a zygote (single diploid
cell)
...

Explain the role of the placenta in the nutrition and gaseous exchanged of the
developing embryo
The embryo can’t digest, breathe, or excrete
...
Waste products are taken out of the embryo and put back into the mother’s
bloodstream for her to excrete them
...
If any force is applied on the uterus
wall, it will not harm the embryo
...


Recall the roles of oestrogen and testosterone in the development of secondary sexual
characteristics
In females – oestrogen causes the beginning of the menstrual cycle
...
There is body hair and development of sexual
organs
...

Describe the birth process and explain the advantages of breast feeding
There are 4 stages of the birth
...
2)
Full cervix dilation to the delivery of the baby
...
4) After birth recovery – the mother is monitored to make sure there is no
uterus bleeding or other complications
...
Also, mothers are less likely
to develop osteoporosis later in life and have a lower risk of breast and ovarian cancer
...
This is growing from a zygote
(one celled) to an adult human being
...
There are 10 days of gestation
...
It occurs around 8 weeks after
fertilisation (10th week of pregnancy till birth)
...
Adulthood is 20+ years
...

Describe the methods of contraception by hormonal, barrier and natural methods,
intra-uterine devices and sterilisation
...

There are various methods of contraception
...
The advantages are that its very
effective, side effects are uncommon and it helps to ease period pains and reduces the
chance of some cancers
...
You had to take it at exact time intervals and it can’t
be used with certain medical conditions (an example would be high blood pressure)
...
The next one is barrier methods; condoms
...
It’s very effective and there are no medical risks or side
effects and they provide protection against STIs
...
Natural methods
involve fertility awareness
...
Example; body temperature and cervical secretions
...
It needs proper instructions and takes a few cycles to learn properly (takes 3-6)
...

Recall that the nucleus of a cell contains chromosomes on which genes are located
There are loci where genes are located on a chromosome, in a nucleus of a cell
...

Recall that genes exist in alternative forms called alleles which give rise to differences
in inherited characteristics
...
The different forms are called alleles
...
Homologous chromosomes carry
genes for the same features in the same sequence
...
For example: Aa and Bb (big A is dominant and small a is recessive)
...

Recall the meaning of the terms dominant, recessive, homozygous, heterozygous,
phenotype, and genotype, dominance, diploid and haploid
Understand the inheritance of the ABO blood groups, and recall the terms multiple
alleles and codominance
The ABO blood group is inherited from the parents
...
This is an example of codominance and multiple alleles
...
Multiple alleles are when there are more than two alleles in a
gene
...

Understand the patterns of monohybrid inheritance using a genetic diagram
Monohybrid inheritance is the inheritance of one gene
...

Understand how to interpret family pedigrees
A pedigree diagram shows a specific gene in the family
...
If coloured in, it represents an allele and if it’s white it
represents another allele
...
Sickle cell anaemia is also caused by a
recessive allele
...
One pair of chromosomes controls
the gender of the person- XX is female and XY is male offspring
...

Understand the pattern of sex-linked inheritance, including haemophilia and red-green
colour blindness
X-linked inheritance means that the gene causing the disorder is located in the X
chromosome
...
X-linked recessive genes are
expressed in females only and only if there are 2 copies of the gene
...
In males, there only needs to be one copy of an x-linked recessive gene in
order for the disorder to be expressed
...
This
means that the person can’t tell the difference between red and green
...
Haemophilia means that the blood cannot clot properly due
to a lack of clotting factor
...
Males are also affected more
...

Gametes contain a random selection of genetic information from each parent
...
Therefore, offspring are genetically
different to their parents
...

The diploid number of chromosomes is 46 and the haploid number is 23
...

Variation is the differences between the members of species
...
Environmental variation is caused by any factors after
birth
...
Some variation is a bit of
both
...
A mutation
is a changed in the DNA sequence
...

Recall that many mutations are harmful but some are neutral and a few are beneficial

A lot of mutations are harmful; an example is genetic diseases such as cystic fibrosis
...
An example – having a
different hair colour
...

Understand that mutant organisms can increase in population by natural selection
Darwin’s theory – Variations in the species exist naturally
...
There is a lot of environmental
pressure and this determines the reproductive success of the individual
...
Over generations, the individuals more successful in reproduction populate the
species
...
This is called evolution
...

Recall that the incidence of mutations can be increased by exposure to ionising
radiation (for example gamma rays, x-rays and ultraviolet rays) and some chemical
mutagens (for example chemicals in tobacco)
There are things that make you more likely to have a mutated gene, these include ionising
radiation and chemical mutagens for example the chemicals in tobacco
...

The general course of a disease
...
(ii) Understand the difference between endemic and epidemic diseases
(ii) Endemic disease is a disease that is present in a population or geographic region, at
consistent levels/period of time
...
Epidemic disease is when there is an outbreak which affects a
disproportionally higher number of individuals than normal at a given time
...
(i) Viruses: recall a brief description of
their structure and reproduction
...

A virus is an extremely small, infectious object that only replicates in a living host
...

The proteins of the capsid are encoded for by the nucleic acids
...
The viral capsid may sometimes be surrounded by a viral envelopethis is a lipid bilayer derived from the host cell (the envelope can change rapidly in
response to many factors, allowing the virus to avoid the immune system)
...
Viruses can’t grow/reproduce on their own – which is why they have to
affect the cells in the living organism
...

Bacteria: recall a brief description of their structure, nutrition and reproduction
Each bacterium is a single cell
...
No other proper organelles (mitochondria)
...
A capsule/slime layer outside the cell wall and sometimes
one/more flagella, which beat to move the cell along
...
Not the same as mitosis, because there
is no nucleus & only a single chromosome
...
Many grow on dead material,
rotting it down – decomposers
...

Bacteria as pathogens: recall methods of transmission, treatment and prevention of
spread oh typhoid, tuberculosis and gonorrhoea
...
Lives in the gut wall, causing fever,
vomiting and diarrhoea, caused by the toxins it releases
...
Typhoid bacillus present in faeces of sufferers & spread in drinking water contaminated by
the faeces & food visited by flies which have fed on the faeces
...
Treatment is by antibiotics to kill the bacteria & oral rehydration therapy
...

Tuberculosis – caused by another bacillus called Mycobacterium tuberculosis
...
Death is from destruction of lung tissue
...
Common in crowded conditions
...
Treatment by prolonged
used of multiple antibiotics
...

Gonorrhoea – caused by a coccus called Neisseria gonorrhoea
...
Symptoms – discharge of pus from penis/vagina
...
Avoided by avoiding sexual intercourse &
wearing a condom
...


Fungi: recall methods of transmission, treatment and prevention of spread of thrush
and athlete’s foot
...
These include candida albicans which caused thrush; a painful
infection of the mouth/vagina/penis
...
Outbreaks occur
when immune system is disabled (during AIDS)/ during a course of antibiotics to treat
bacterial infection
...
Trichophyton causes athlete’s foot
...
Transmission is by spores, often found on floors of
sports changing rooms
...

Disease caused by other parasites: (i) The parasite schistosoma: recall its nutrition and
life cycle
...
The worms live
inside blood vessels of several organs, feeding on the host’s red blood cells
...
Bilharzia is a chronic (long lasting) rather than an

acute disease
...
It makes use of a
secondary host in its life cycle
...
Immature forms called larvae are released by the
snails, swim in the water & burrow through the skins of people bathing in water,
something eggs themselves wouldn’t be able to do
...
Transmission is reduced by
improved sanitation so hat urine and the faeces do not contaminate freshwater lakes and
rivers
...


Understand the role of non-pathogenic bacteria and fungi useful to humans in the
decomposition of organic matter
Fungi play an important role in many aspects of human life, including medicine, food and
farming
...
Yeast is used in production of beer, wine and bread
...
Decomposers are non-pathogenic bacteria
...
They are also important in biotechnology, genetic engineering and waste disposal
...
Organic matter – nitrogen, sulphur phosphorus
...
Values and knowledge influence people’s views of life and
define the way humans act
...
Example: provision of resources like water, food energy, land for farming etc
...
They reorganise
existing eco-systems to achieve new ones that seem more effective for example; knocking
down a forest for new building projects
...

Explain the dependence on green plants for supplies of food and oxygen

Green plants photosynthesis by taking in co2 and releasing oxygen
...
Without photosynthesis, this would replenish
fundamental food supply
...
Primary producers turn light energy
into chemical energy
...
The
secondary consumes the primary and the tertiary eats the secondary consumer
...

Describe the transfer of substances and of energy along a food chain and understand
that only about 10 per cent of energy is transferred from one trophic level to the next
As one thing consumes another, the energy inside it (e
...
fat & vitamins) get transferred
to the consumer
...
g
...

Only a small amount of the producers original energy is stored by the consumer (approx
...
The amount of energy at each trophic level decreases as it moves through an
ecosystem
...

Understand the hygienic methods of food preparation, storage and preservation
Food protection methods are intended to prevent contamination and spoilage of foods
...
These contaminate the food with the microorganisms
...
All surfaces that come into contact with food should be clean
...
All utensils must be kept clean by
regular washing
...
Floors and
surfaces should be cleaned and drained
...

Raw food and cooked food must never touch each other as raw food can contaminate
cooked food
...
Food preservation allows food to be kept for extended period of time,
without losing it nutritional quality & avoiding the growth of unwanted microorganisms
(using high temperature such as boiling/cooking/chilling/freezing food
...
)

Understand the scientific principles used in the purification, distribution and storage
of water
...
Without it there would be no life on
earth
...
River water is usually contaminated and must be purified for drinking purpose
...
The rain water must be filtered
and boiled for at least 10 minutes
...
2)
Sedimentation – this allows some solids to settle
...
3) Filtration – the sand particles become coated with a jelly-film film which traps
bacteria
...
Water is stored in large tanks and supplied to houses through pipes
...
They take up sunlight and oxygen,
many fish and organisms die through the harmful chemicals in the water
...

Explain how eutrophication can result from leached minerals from excess nitrogen
fertiliser or treated sewage
Eutrophication is an increase in the concentration of chemical nutrients in an ecosystem to
an extent that increases in the primary productivity of the ecosystem
...
Another example is the increase of
phytoplankton in a water body as a response to increase levels of nutrients
...
There are some ecological impacts, for example, decrease
biodiversity, changes in species composition and dominance, toxicity affects
...
When in the atmosphere, they can dissolve in rain water to create acidic rain
...

Acid rain can also change the pH in soils and rivers, meaning that some species cannot
survive in that area
...
Sulphur
dioxide + water leads to acid rain
...

Greenhouse gases absorb heat reflected by the earth
...
These gasses can change the climate by keeping

in too much heat
...

Explain how human activities contribute to greenhouse gases
Fossil fuels: 1) Combustion of fossil fuels from industries, cars and domestically
...
2) Methane – cows produce methane
and this is through agriculture, natural gas distribution and landfills
...
3) Solvents (CFC), refrigeration agents and other industrial processes cause
ozone depletion and also an increase in halocarbon gas concentrations (ozone is a GG gas
that is continually produces and destroyed in the atmosphere by chemical reactions
...
g
...
Human activities e
...
surface mining and
industrial processes have increased dust (aerosols) in the atmosphere
...
These waves travel from the
sun through the earth’s atmosphere and warm it up
...
Many of these waves escape the earth’s atmosphere, but some are
absorbed by greenhouse gases, meaning the heat is trapped within the earth’s
atmosphere
...
The consequences are; melting of the ice caps, raised sea levels,
change in ocean and wind current – results in climate change and affects the ecosystem
...
Normally the nutrients are rained into the soil,
absorbed by plants, shared in the leaves (when they die) and then digested by
decomposers, so that it’s back in the soil
...
In addition, the soil is not protected by plants, so that when
it rains, there’s a higher rate of surface runoff (means that nutrients will remain in soil)
...
If there are fewer plants, less water is
evaporated into the atmosphere which means less cloud, rain, and leads to droughts
...
Forests carbon
sinks and uses more carbon than they release
...
When these forests are cut down,
this process is lost and trees are usually burnt, releasing more CO2 into atmosphere (when
forests are cut, animals lose their homes – causes collapsing of food chains)
...
Energy that is
emitted from a source is referred to as radiation
...
Ionising radiation is radiation can cause an atom
to become charged/ionised
...
Ultraviolet light causes damage to the skin this comes from the sun
...
In x-rays, a low
level of ionising radiation is used to produce images from the inside of a body
...




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