Human Biology

12. Disease
12.1 understand the general course of a disease as: infection, incubation and symptoms

Method of Infections

1) Droplet Infection – Causes respiratory diseases. The organisms are carried in tiny droplets
through the air when an infected person coughs or sneezes and are inhaled by others.

Example: common cold, influenza, tuberculosis, pneumonia.

2) Contaminated Water/Food – Often infect regions of the gut. The organisms colonize a suitable
area of the guy and reproduce. They are passed out with faeces and find their way back into the
water.

Example: typhoid, polio, cholera (water), salmonella (food), listeriosis (food)

3) Direct Contact – Many skin infections such as athletes’ foot are spread by direct contact with an
infected person or contact with a surfre carrying the organism. Some diseases are transmitted by
direct contact with bodily fluids. (Ebola, Hepatitis B)

Example: Athlete’s foot, Ebola, Ringworm

4) Sexual Intercourse – Organisms infecting the sex organs can be transmitted during sexual
intercourse. Some are transmitted by direct body contact (fungal thrush which causes
candidiasis) and others are transmitted in semen or vaginal secretions (AIDS). Some such as
syphilis can be transmitted in saliva.

Example: AIDS, gonorrhoea, chlamydia, syphilis

5) Animal Vectors – The pathogen is transmitted when the insect bites humans in order to feed on
blood. Flies can carry microorganisms from faeces onto food.

Example: Malaria, sleeping sickness, typhoid

12.2 know that diseases are caused by pathogenic microorganisms

- A disease is a condition with a specific cause in which a part of the body function abnormally and less
efficiently.

- Microorganisms are responsible for causing infectious diseases.

1) Bacteria – Release poisons called toxins as they multiply. These toxins mostly affect cells in the
digestive system and are not contaminated by the blood because WBS will fight the toxins in the
blood.

Example: Typhoid, Cholera, Tuberculosis, Gonorrhoea, Pneumonia

 2) Viruses – Enter a living cell and disrupts the cell’s metabolic system. The genetic material of the
virus takes over the cell and instructs it to produce more viruses.

Example: HIV, Influenza, Measles, Poliomyelitis, Ebola

3) Fungi – Grows in or on the body and secretes digestive enzymes onto the tissues, breaking them
down. Some fungi secrete toxins and some causes allergies.

Example: Athletes’ Foot, Thrush, Ringworm

4) Protozoa – There is no set pattern.

Example: Malaria, Sleeping sickness

12.3 describe the structure and reproduction of viruses

1) A virus reproduces by entering the host cell and taking over the cells metabolic system to make
more virus particles.
2) After many virus particles has been made, the host cell dies and the particles are released to
infect more cells.

12.4 describe methods of transmission, treatment and prevention of the spread of Ebola and HIV
(human immuno-deficiency virus), the virus that causes AIDS

HIV

Infection:

1) The genetic material of HIV is RNA. The virus makes DNA from the RNA and this DNA becomes
incorporated into the DNA of the T-helper cell.
2) At some point in the infection, the HIV DNA is activated. It then instructs the lymphocyte to
make HIV proteins and more RNA.
3) The HIV proteins and RNA are assembled into new virus particles.
4) Some of the HIV proteins end up as antigens on the surfAC of the cells.
5) These HIV proteins on the lymphocyte are recognized by the immune system as foreign and are
destroyed.
6) The assembled virus particles escape to infect other lymphocytes.

Transmission:

1) Unprotected sexual intercourse (without using condoms)

2) Blood-to-blood contact (Drug users sharing needles)

Prevention:

1) Use of condoms
2) Drug users using new needles
3) Limiting sexual partners
Ebola

Transmission:

1) Natural hosts of the virus are African fruit bats.

2) Ebola then spreads from person to person by direct contact with bodily fluids.
3) Ebola can also be transmitted from infected materials such as bedding.
4) The disease is highly infectious.

Symptoms:

1) Incubation period is 2-21 days.

2) First symptoms are fever, muscle pain, headache and sore throat.
3) These are followed by vomiting, diarrhoea, rash ad external bleeding.
4) Laboratory tests show low white blood cells and platelets count.

Treatment: Oral Rehydration Therapy

Prevention:

1) Reducing risk of transmission of the virus from animals – avoiding contact with animas, wearing
gloves and cooking meat thoroughly.
2) Reducing risk of transmission from infected patients – wearing gloves and protective clothing.
3) Reducing risk of transmission by sexual intercourse
4) Containing the outbreak – safe burial of the dead, isolating infected people, etc.

12.5 describe the structure, nutrition and reproduction of bacteria including the interpretation of
bacterial growth curves

Reproduction:

1) Bacteria reproduce asexually by a process called binary fission.

2) The cell grows until it has doubled in length.
3) In the cytoplasm, the single chromosome is copied and the two copies separate to opposite ends
of the cell.
4) The cell membrane folds inwards, forming a double layer across the middle of the cell.
5) Two cell walls are then made and the two daughter cells separate and grow.

Growth Curves:

1) Lag phase – Bacteria adjust to their new environment and waits for the mature age to
reproduce.
2) Growth phase – Growth then accelerates where the cell divides in equal time intervals.
3) Stationary phase – Rate of formation of new cells equal to the rate of cells death.
4) Death phase – Number of cells that dies over takes the number of new cells due to limiting
factors.
12.6 investigate the effects of antibacterial agents and antibiotics on the growth of bacterial culture

1) A petri dish containing a nutrient agar culture of a harmless bacterium (such as Staphylococcus
albus) is prepared.
2) Metal forceps are sterilised by briefly placing them in the flame of a Bunsen burner.
3) The sterilised forceps are used to place a paper disc containing penicillin on the agar surface
4) It is important that the lid of the Petri dish is opened as briefly as possible, to prevent other
microorganisms entering the dish.
5) Further discs are added, containing other antibiotics or different concentrations of antibiotics.
6) A control disc containing no antibiotic is also added on the agar.
7) It is placed in an incubator for 48 hours.
8) The effectiveness of an antibiotic is proportional to the diameter of the clear area.

12.7 know the methods of transmission, treatment and prevention of the spread of cholera and
gonorrhoea.

Cholera

Transmission:

1) Person to person through contaminated water.

2) Secrete a toxin that upsets the functioning of the epithelium lining the intestine.

Symptoms:

1) The toxin causes loss of water and salts from the blood into the intestine, resulting in diarrhoea
so the body becomes dehydrated.
2) The patient feels weak with a rapid heart rate, low blood pressure and muscle cramps.
3) The loss of fluid and shock can result in death within hours.

Treatment: Oral Rehydration Therapy

Prevention: Drinking clean water, good hygiene

Gonorrhoea

Transmission: A sexually transmitted disease passed on during sexual intercourse.

Symptoms:

1) Swollen penis and discharge of pus from the penis and pain when urinating.
2) Fever and headaches
3) Discharge from vagina or bleeding between menstrual periods.
4) Can lead to infertile if untreated

Treatment: Antibiotics

Prevention: Avoid sexual intercourse or use a condom

12.8 explain the importance of oral rehydration therapy

1) Diarrhoea causes water loss from body and the body becomes dehydrated.
2) This affects metabolism and osmotic balance of the body.
3) As a result, oral rehydration therapy is given which rehydrates the body.
4) It contains water containing salts.

12.9 know the methods of transmission, treatment and prevention of the spread of athlete’s foot

Transmission:

1) Athletes’ Foot usually grows on the warm, moist skin between the toes.
2) Fungal spores may be transferred to the skin from the air or floor.

Treatment: Antifungal Drugs

Prevention:

1) Avoid changing rooms

2) Wear cotton socks to stop feet from becoming moist
3) Keep toenails short

12.10 explain the role of the mosquito (malaria) and housefly (typhoid) in transmitting causative
agents of disease

Malaria

1) An uninfected female mosquito sucks blood from an infected person and takes in sex cells.
2) Fertilisation occurs in the body of the female mosquito. The zygotes develop into malarial
parasites.
3) Infected female mosquito injects the malarial parasite into the bloodstream.
4) The malarial parasite rapidly enters liver cells and changes form. The new form ruptures the liver
cells, escapes into the bloodstream and infects red blood cells.
5) Infected red blood cells burst and release more parasites and sex cells.

Typhoid

1) House flies do not bite humans but will feed on human food if left uncovered.
2) They are attracted to human faeces and transmit many bacteria and viruses on their body and in
their saliva.
3) The microorganisms are passes to humans when they eat the food.

12.11 describe the treatment and prevention of the spread of malaria and typhoid

Malaria
Symptoms:

1) Cold Sweats and Fever

2) Vomiting
3) Joint pains and anaemia
4) Coma and death

Treatment: Quinine

Prevention:

1) Using insecticides to kill adult mosquitoes

2) Draining swamps and pools to destroy their natural habitat
3) Biological control – Tilapia
4) Insect repellents, Long-sleeved shirts, Sleeping nets

Typhoid

Symptoms:

1) Stomach cramps
2) Constipation or diarrhoea
3) Vomiting and delirium (mental confusion)
4) Heat inflammation and multiple organ failure.

Treatment:

1) Vaccines
2) Antibiotics such as penicillin
3) Oral Rehydration Therapy

Prevention: Good sanitation and hygiene

12.12 understand the antibody-antigen reaction

1) Different bacteria have different shaped antigens on their surface.

2) Lymphocytes memories and recognises the antigens
3) The lymphocyte binds onto the antigens.
4) The lymphocyte becomes activated and starts to divide rapidly.
5) When certain lymphocytes are activated, the start to produce specific antibodies which are
released into the blood.
6) They bind onto the antigens and kill them.

12.13 explain how vaccines work to prevent the spread of disease

1) Dead or inactive pathogens are injected into the body.

2) The body produces antibodies against the antigens.
3) Memory cells are also created to provide long time immunity.
12.14 understand the differences between natural and artificial immunity and active and passive
immunity

Active immunity – happens when we produce our own antibodies to an antigen.

1) Natural Active – Response to an infection

2) Artificial Active – Result of a vaccination

Passive immunity – receives antibodies from somewhere else.

1) Natural Passive – Antibodies passed from mother to foetus across placenta.

2) Artificial Passive – Antibodies are given by injection

12.15 know the sources and role of antibiotics

1) Antibiotics are chemicals that kill microorganisms or reduce their growth.

2) They are mainly used in medicine to treat bacterial infections.
3) Do not work on viruses
4) Natural antibiotics are produced by bacteria and fungi.

Penicillin

1) Interferes with manufacture of bacterial cell wall.

2) Weakens cell wall – water enters by osmosis and bursts the cell
3) Bactericidal Antibiotic

Nalidixic Acid

1) Interferes with DNA replication

2) Bacteria are not killed but cell division is impossible so they cannot multiply.
3) Bacteriostatic Antibiotic

Tetracycline

1) Interferes with protein synthesis

2) Stops production of enzymes
3) Bactericidal Antibiotic

12.16 explain how resistant pathogens such as MRSA arise and why they are a cause for concern.

1) Resistance starts when a random gene mutation gives a bacterium resistance to a particular
antibiotic.
2) The new resistant bacterium has a big advantage over non-resistant bacteria of the same type.
3) The resistant bacteria will survive and multiply in greater numbers.
4) They will not be killed by antibiotics so the antibiotic is no longer effective in controlling the
disease.
12.17 understand the role of non-pathogenic bacteria and fungi (decomposers) useful to humans in
the decomposition of organic matter (details of other bacteria in the nitrogen and carbon cycles are
not required)

12.18 know the processes of sewage treatment in modern sewage works and a pit latrine including the
role of aerobic and anaerobic microorganisms in sewage breakdown

Sewage Treatment

1) In the first settling tank, solids such as grits and rocks are removed.
2) Sludge forms
3) Anaerobic bacteria break down the sludge
4) Methane gas is produced.
5) The leftover sludge is then used as fertiliser.
6) The aerobic bacteria break down the organic material in effluent into harmless inorganic
substances.
7) Then the water is disinfected by chlorination.

Pit Latrine

1) Pit latrines can be improved by making the base stable so that there are no cracks in the
concrete floor to avoid hookworm transmission and larvae from growing.
2) Moreover, the holes should be made large enough to avoid urine from splashing out to the walls
where flies, bacteria and fungi will thrive.

4. Bones, Muscles and Joints

4.1 describe the structure and function of the main parts of the skeleton:

1) Axial skeleton: vertebral column, cranium, ribcage and sternum (breastbone)

2) Appendicular skeleton: scapula, clavicle, pelvis and limb bones

Long Bone – made of cells called osteocytes

1) Spongy Bone (middle)

- Fewer calcium salts so less hard
- Filled with bone marrow in a hollow central cavity
- The marrow stores fat and produces blood cells
2) Compact Bone (outside)
- Harder material
 - Osteocytes arrange themselves in rings called Haversian systems around canals containing blood
vessels and nerves
- The osteocytes secrete calcium phosphate salts which makes up the matrix (bone filling)
3) Epiphysis (end)
- Cartilage acts as a cushion between two bones at a joint
- Cartilage is a tough but flexible tissue containing chondrocytes which secretes a matrix

4.2 explain the functions of joints using the elbow, shoulder and a cartilaginous intervertebral joint as
examples

1) Freely Moveable Joints

- Hinge Joints can only be moved in one direction when bending your arm (elbow)
- A ball and socket joint allows movement in any direction (shoulder)
2) Partially Moveable Joints – Joints between vertebrae allows a small movement when the spinal
column bends
3) Immovable/ Fixed Joints – Between the bones of the skull

4.3 describe the structure of a synovial joint

1) Moveable joints are called synovial joints which contains a liquid called synovial fluid secreted by
the synovial membrane.
2) Synovial fluid is oily and acts as a lubricant, reducing friction between the end of the bones.
3) The end of each bone has an articulating surface covered with a smooth layer of cartilage.
4) Cartilage acts as a shock absorber between the ends of the bones.
5) The joint is surrounded by a tough fibrous capsule held together by ligaments which runs from
one bone to the other across a joint.
6) They allow movement but prevent the bones from becoming dislocated.

4.4 explain the relationship between voluntary muscles and bones to bring about movement
illustrated by the biceps and triceps muscles and associated bones in the arm and shoulder

1) Muscles are attached to bones

2) They work as antagonistic pairs.
3) As the bicep contracts, it shortens the muscle and pulls the tendons which attaches the muscles
to the bone.
4) The tendon is not elastic so it pulls the bone as well and raises the forearm.

4.5 understand the dietary factors controlling the healthy development of muscle and bone

1) Calcium is needed to make the calcium salts in the bone matrix

2) Vitamin D is needed to absorb calcium
3) Lack of Vitamin D causes rickets

4.6 understand the causes and symptoms of osteoporosis

1) Osteoporosis is a medical condition that affects elderly people.

 2) Bones loses calcium salts and become porous and less dense so they break easily.
3) Symptoms include pain when walking and height decreases.
4) Women are particularly vulnerable after the menopause due to hormone changes.
5) There is no cure for osteoporosis

5. Coordination
5.1 know the structure of neurones: sensory, motor and relay

5.2 know the basic plan of the central nervous system

5.3 know the main areas of the brain and their functions including the cerebral hemispheres,
cerebellum, mid brain, pituitary gland and hypothalamus

1) Cerebrum: Largest part of the brain

- Made of two cerebral hemispheres.
- Source of all conscious thoughts
- Outer layer is the cerebral cortex with many folds
- Three main functions:
(1) Sensory Areas – receive and process information from all sense organs
(2) Motor Areas – where all voluntary actions originate
(3) Origin of ‘higher activities’ – memory, reasoning, emotions and personality
2) Cerebellum
- Coordinates the contraction of sets of muscles
- Maintains balance
3) Medulla
- Connects the spinal cord with the brain
- Controls basic body activities such as breathing and heartbeat rate.
4) Pituitary Glands
- Located at the base of the brain below the hypothalamus
- Secretes hormones into the blood

5.4 know the structure and functions of the spinal cord and the structure of a reflex arc

1) The stimulus is detected by temperature or pain receptors in the skin.

2) These receptors generate impulses in the sensory neurones.
3) The impulses enter the CNS through a part of the spinal cord called the dorsal root.
4) In the spinal cord, the sensory neurones connect by synapses with short relay neurons which in
turn connect with motor neurones.
5) The motor neurones emerge from the spinal cord through the ventral root and send impulses
back to the muscles of the arm.
6) These muscles then contract, pulling the hand away.

5.5 understand that the body contains receptors that can detect the stimuli for light, temperature,
pressure/pain and taste
5.6 describe the pathway taken by a nerve impulse to cause a response to a stimulus

5.7 practical: investigate the number and position of sensory receptors, such as touch and temperature
receptors in the skin

1) Use a pin or paperclip.

2) Blindfold the student so that they cannot see when the pin touches the skin.
3) One point or two points can be placed on the student’s hand at once randomly, and the student
must report whether they feel one or two pin.
4) Repeat the experiment with different students.
5) Use the same paperclip.
6) Calculate the average number of correct answers and the compare this for different parts of the
body.

5.8 understand how nerve impulses are initiated, the direction of movement of an impulse along a
neurone and transmission across a synapse. (Neurotransmitters)

5.9 understand the 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 know the role of hormones in growth and development

5.10 understand the differences between the nervous and hormonal systems

5.11 explain the structure and function of the eye in:

• Focusing on near and distant objects

1) Near
- Ciliary muscles contract.
- Suspensory Ligaments Slackens
- Lens becomes fat
- Refracts more Light
2) Distant
- Ciliary muscles relax
- Suspensory Ligaments Tightens
- Lens becomes thin
- Refracts less light

• Responding to changes in light intensity

1) Bright
- Radial Muscles Relax
- Circular Muscles Contract
- Pupils becomes smaller
- Allows less light in
2) Dim
- Radial Muscles Contract
 - Circular Muscles Relax
- Pupils become bigger
- Allows more light in

• Stereoscopic vision allowing better judgment of distance

1) Use two students; one to throw the ball and the other to catch the ball.
2) Count how many times the ball is dropped.
3) Repeat this with one eye closed.
4) Keep the number of throws the same and the distance between the two students.
5) Compare the results.

5.12 understand eye defects and their treatment, i.e. long sight, short sight, astigmatism, and
cataracts, and the use of corneal transplants

1) Long Sight
- Difficulty focusing on near objects
- Lens are not convex enough (too flat)
- Eyeball is too short from front to back
(1) Light rays from a nearby object are focused behind the retina.
(2) Image falling onto the retina will be out of focus
- Corrected using a convex lens to converge the light before it enters the eye.
2) Short Sight
- Difficulty focusing on distant objects
- Lens is too convex
- Eyeball is too long from front to back
(1) Light rays from a distant object are focused in front of the retina.
(2) Image falling onto the retina will be out of focus
- Corrected using a concave lens to diverge the light before it enters the eye.
3) Astigmatism
- A minor defect in the structure of the eye that causes blurred vision
- Corrected by wearing glasses or contact lens
4) Cataracts
- Lens of the eye becomes cloudy and opaque.
- Treated by surgery where the affected lens is removed and replacing it with artificial lens.
5) Corneal Transplants – The diseased cornea is removed and replaced with a cornea taken from a
donor

5.13 explain the structure and function of the ear in balance and hearing

Hearing

1) Sound is detected through the outer ear by the pinna down to the eardrum.
2) The ear drum then vibrates and transfer vibrations to the ear ossicles (malleus, incus, stapes).
 3) The ear ossicles transfer vibrations from the eardrum to the oval window and amplifies the
vibrations transferred.
4) The cochlea converts the vibrations to nerve impulses and transmits them to the brain via the
auditory nerve.
5) The eustachian tube allows air to pass from the throat. This equalised the pressure on either side
of the ear drum and helps keeps the malleus in contact with the eardrum.

Balance

1) The semi-circular canals as well as the sacculus and utriculus are involved in maintaining
balance.
2) In the swellings at the end of the semi-circular canals, there are hair cells embedded with a jelly-
like mass called a cupula.
3) Movement of the fluid in the semi-circular canals causes the cupula to pull on the hair cells
which stimulates them to send nerve impulses to the brain.
4) The sacculus and utriculus also contain hair cells embedded by otolith.
5) The weight of otolith pulls on the hair, stimulating the hair cells and producing nerve impulses.
6) This gives information to the brain about the position of the head.

5.14 understand how prolonged exposure to high noise levels affects the functioning of the ear and
hearing

1) Exposure to a very loud noise can rupture the eardrum or damage the delicate bones in the
inner ear.
2) It can cause temporary deafness and may also cause a ringing sound in the ears called tinnitus.
3) Prolonged exposure to high noise levels can result in permanent hearing loss.

5.15 practical: investigate the range of frequency audible to the human ear

1) Use a speaker and play sounds from a range of frequencies starting from low to high frequency.
2) Determine the frequency using an oscilloscope.
3) Count the minimum and maximum frequency that can be heard by the person.
4) Note down when it cannot be heard.
5) Repeat the investigation with several people of the same age.

5.16 understand the meaning of the term 'drug' and distinguish between legal and illegal drugs,
including:

• the dangers of heroin, cannabis and cocaine

• the action of common painkillers such as paracetamol on the nervous system.

- Drugs are chemicals that affect the normal chemical reactions taking place in a person’s body.
They may have a physiological effect when taken into the body.
Cannabis

1) Contains a psychoactive substance called tetrahydrocannabinol (THC).

2) Sense of relaxation, cheerfulness and increased awareness of sounds and colours.
3) Hallucinations
4) Dangerous to the lungs

Heroin

1) Strong painkiller – modified form of morphine

2) High, Depressant drug that slows down the nervous system
3) Rapidly develop a tolerance
4) Withdrawal Symptoms – Sweats, Chills, Anxiety & Depression

Cocaine

1) Local anaesthetic
2) White powder which is inhaled
3) Powerful, Stimulant Drug that affects synapses in brain
4) Extreme happiness, energy and alertness
5) Increases heart rate and blood pressure to dangerously high levels

Paracetamol

1) Treat common aches and pains

2) Reduce high fever
3) Inhibits an enzyme that controls the production of prostaglandins.
4) Overdosage can cause permanent liver damage and death

5.17 describe the damaging effects of alcohol on the nervous system and liver and the behavioural
consequences of excessive and long-term drinking

Alcohol

1) Slows down the nervous system

2) Blurred vision and slurred speech
3) Coma and death
4) Cirrhosis Disease – dried liver – unable to produce bile
5) Causes gene mutation – leading to cancer

5.18 describe the causes, symptoms and treatments of mental illness, including schizophrenia and
depression
Schizophrenia

Cause:

1) High levels of dopamine

2) Stress
3) Drug Abuse

Symptoms:

1) Hallucinations
2) Delusions
3) Paranoia

Treatment:

1) Talking Treatments
2) Cognitive Behavioural Therapy (CBT)

Depression

Cause:

1) Stress
2) Drug Abuse
3) Trauma

Symptoms:

1) Restless
2) Suicidal Thoughts/Actions

Treatment:

1) Talking Therapy
2) CBT

5.19 describe the causes, symptoms and treatments of Alzheimer's disease, vascular dementia and
Parkinson's disease

Alzheimer’s Disease

Cause: Build-up of two proteins in brain cells called amyloid and tau

Symptoms:

1) Forgetting recent events, names and faces

2) Becoming repetitive
3) Speech problems

Treatment:

1) Neurotransmitter called acetylcholine

 2) Activities that stimulate the brain

Vascular Dementia

Cause: Diseased and damaged blood vessels in the brain

Symptoms Memory loss

Treatment: Reduce blood pressure and cholesterol

Parkinson’s Disease

Cause: Death of certain neurons which produces dopamine

Symptoms:

1) Tremor
2) Speech Problems
3) Muscle Stiffness

Treatment:

1) Levodopa – natural chemical that converts into dopamine

2) Dopamine Agonists – mimics dopamine actions

9. Internal Transport
9.1 know the composition of the blood: red blood cells (erythrocytes), white blood cells (phagocytes
and lymphocytes), platelets and plasma

9.2 understand the role of plasma in the transport of carbon dioxide, digested food, urea, hormones
and heat energy

9.3 know the role of tissue fluid and explain how this arises as a result of pressure differences and its
subsequent drainage into the lymphatic system

1) Tissue fluid surrounds cells and carries oxygen and glucose from the blood in the capillaries into
the cells.
2) It also carries waste from the cells.
3) It is formed from the plasma under high pressure.
4) Excess tissue fluids drain into the lymph vessel.

How tissue fluid is formed

 1) Artery end has a higher pressure.
2) Capillary walls have pores so the pressure forces water out.
3) Small molecules are also forced out, leaving large molecules in the blood.

9.4 explain how red blood cells are adapted for oxygen transport

9.5 understand the role of ABO blood groups and their importance in blood transfusions

1) Each red blood cell has an antigen.

2) There are antibodies in the plasma that destroys red blood cells with a particular antigen.
3) Blood group A has the antibody “Anti-B” and can receive blood from A and O
4) Blood group B has the antibody “Anti-A” and can receive blood from B and O
5) Blood group AB has no antibodies and is a universal recipient.
6) Blood group O has the antibody “Anti-A” and “Anti-B” and is a universal donor.
7) It is important that blood from the correct group is given or else the blood may be rejected and
cause the RBCs to agglutinate
8) This causes blood vessels to become blocked and lead to a heart attack.

9.6 understand the role of white blood cells including phagocytosis and antibody production (details of
plasma cells are not required)

9.7 describe the importance of blood clotting and the role of enzymes in causing the conversion of
fibrinogen into fibrin (the names of other intermediates and enzyme names are not required)

1) Due to exposure to air, thrombokinase converts prothrombin into thrombin.

2) This turns fibrinogen into fibrin.
3) Fibrin forms a mesh over the wound.
4) This prevents further blood loss and entry of pathogens.

9.8 compare the structures of arteries, veins and capillaries, and understand their roles including the
pulse

1) When the blood leaves the heart through the aorta, the blood leaves in short bursts of pressure,
stretching the walls of the aorta.
2) When the ventricle of the heart relaxes, the stretched section of the aorta recoils, increasing the
pressure inside it.
3) The wave of stretching followed by constriction passes along the aorta through the arteries.
4) This is the pulse.

9.9 know the general plan of the circulatory system to include the blood vessels to and from the heart,
the lungs, the liver and the kidneys

9.10 know the structure of the heart and how it functions

9.11 describe the causes, prevention and treatment of heart disease including:

• The effect of diet and exercise

1) Diet – A diet that is high in fat increases blood cholesterol which blocks blood vessels that can
cause heart attacks.
2) Exercise – Regular exercise helps reduces blood pressure and strengthens the heart.

• The use of stents, artificial hearts and transplants

Stent

1) Catheter is inserted into a blood vessel.

2) At the end of the catheter, there is a small inflatable balloon with an expandable mesh called a
stent around the balloon.
3) The balloon is inflated, causing the stent to expand and the cholesterol is pushed against the
wall of the arteries.
4) The balloon is then deflated and the catheter is removed, leaving the stend behind.
5) This widens the blood vessel so more blood can flow.

9.12 understand the problems associated with heart transplants

1) The antigens on the cells of the organ to be transplanted will be recognised by the recipient’s
body as foreign.
2) Lymphocytes will then produce antibodies to destroy these foreign cells.
3) This is what is meant by organ rejection.

9.13 describe the use of statins and plant stanol esters in the treatment and prevention of circulatory
disorders

Statins

1) Chemicals that lower blood cholesterol levels

2) Inhibits the enzyme involved in the synthesis of cholesterol.

Plant stanol esters

1) Lower blood cholesterol levels

2) Naturally found in plants and in vegetable oil

9.14 understand the role of beta-blockers in the treatment of circulatory disorders, e.g. heart failure
and angina

1) Beta-blockers are mainly used to manage unusual heart rhythms.

2) Protect against a second heart attack
3) Work on the nervous system
4) Blocks the action of adrenaline at its receptor sites so no flight or fight response
5) This reduces heart rate and stroke volume which means that heart has to work less hard and
needs less oxygen

9.15 explain the terms systolic and diastolic blood pressure

 1) Systolic Blood Pressure – Pressure in the arteries when ventricles contract.
2) Diastolic Blood Pressure – Pressure in the arteries when the ventricles relax.

9.16 describe the causes, prevention and treatment of hypertension

Cause:

1) Genetic Factors
2) High Salt Diet
3) Lack of exercise

Prevention:

1) Eat healthily
2) Exercise regularly
3) Maintain a healthy weight

Treatment: ACE inhibitors

9.17 understand the role of ACE inhibitors in the treatment of high blood pressure

1) When the blood pressure falls, the kidneys produce an enzyme called renin.
2) Renin is released into the blood where it cuts a plasma protein called angiotensinogen into
angiotensin I.
3) ACE then converts angiotensin I into angiotensin II.
4) Angiotensin II is a hormone that acts on blood vessels causing them to constrict, increasing
blood pressure.

9.18 describe how monoclonal antibodies are produced

1) Antigen is injected into a mouse

2) Spleen cells in the mouse produces antibodies.
3) The lymphocytes are taken from the spleen cells and are fused with cancer cells in a culture
medium.
4) Hybridoma cells are formed.
5) Hybridoma cells produce monoclonal antibodies

9.19 understand how monoclonal antibodies work to detect and treat diseases such as cancer

1) To detect cancer, monoclonal antibodies are produced using antigens from the cancer cells.
2) These antibodies can then be used to detect the cancer antigen in tissue samples from other
patients.
3) Monoclonal Antibodies can be used to detect and treat cancer by killing cancer cells or by
interfering with signalling pathways in cells.
11. Reproduction & Heredity
11.1 know that the process of fertilisation involves the fusion of a male and female gamete to produce
a zygote

11.2 describe how a zygote divides to form an embryo

11.3 know the stages of meiosis allowing the production of haploid gametes and its significance in
bringing about variation in a species

1) Prophase I – Chromosomes match with homologous pairs & cross over genes creating
recombinant chromosomes
2) Metaphase I – Pairs of chromosomes lines up in the middle
3) Anaphase I – Chromosomes are pulled away to each end of the cell
4) Telophase I – New nuclei starts to form at each end to make two new cells.
5) Prophase II – Chromosomes thickens
6) Metaphase II – Chromosomes lines in a single fine in the middle
7) Anaphase II – Chromatids are pulled away to each end of the cell
8) Telophase II – New nuclei starts to form at each end to make 4 genetically different haploid cells.

11.4 know the structure and function of the male and female reproductive systems

11.5 understand the roles of oestrogen, progesterone, FSH and LH in the menstrual cycle

11.6 explain the role in pregnancy of the: • hormone progesterone • placenta • amniotic fluid •
umbilical cord.

11.7 know the roles of oestrogen and testosterone in the development of secondary sexual
characteristics

11.8 describe the birth process and explain the advantages of breast feeding

Birth Process

1) Dilation of the cervix

- Allows the baby to pass through.
- The uterus muscles contracts strongly and the amniotic sac tears, allowing the amniotic fluid to
escape.
2) Delivery of the baby
- Strong contractions of the uterus muscles push the baby’s head through the cervix and then
through the vagina.
3) Delivery of the afterbirth
- After the baby has been born, the uterus continues to contract and pushes the placenta out,
together with the membranes that surrounded the baby.

Advantages of Breastfeeding

1) Transfer of colostrum (breastmilk)

2) Contain many antibodies
 3) Giving immunity to many diseases
4) Correct temperature
5) Bonding between mother and baby

11.9 describe an outline of growth and development to maturity, to include growth curves for humans

1) The rate of growth drastically changes between birth and adolescence.

2) Growth is fastest soon after birth known as the infant growth spurt.
3) The rate then decreases rapidly until the child is about 4 years old.
4) Between 4-10 years old, the rate still decreases but slowly.
5) At puberty, there is an increase in the rate of growth known as the adolescent growth spurt.
6) This happens earlier in girls that in boys.
7) There are also changes in body proportions during growth; a baby’s head is very large in
proportion to its body.

11.10 describe the methods of contraception by hormonal, barrier and natural methods, intra-uterine
devices and sterilisation

Barrier Methods

1) Prevents Fertilisation
2) Prevents Transfer of Semen -> Prevents diseases
3) Protects from STDs

1. Condom

- A sheath of fine rubber that fits over the penis and collects the semen before it enters the
vagina.
- The only method that protects again STDs.

2. Diaphragm or Cap

- A dome shaped piece of rubber that a woman inserts in her vagina before intercourse.
- The cap covers the cervix, preventing sperm from entering uterus.

Intra-uterine Devices

- Small pieces of plastic or copper

- An IUD is inserted through the cervix into the uterus
- Prevents a fertilised egg from implanting in the uterus lining

Hormonal Methods

- Taking oral contraceptive pills containing a mixture of oestrogen and progesterone which
prevents production of FSH and LH.
 - Ovulation does not take place.

Sterilisation

- Vasectomy: Sperm ducts are cut and tied to prevent sperm passing to the penis.
- Man can still ejaculate but the semen will contain no sperm.
- Tubal Ligation: Oviducts are cut to prevent eggs from passing to the uterus.

11.11 describe the advantages and disadvantages of each contraceptive method

Natural Methods – High failure Rate

Diaphragm – Medical examination needed. Not simple to use.

Condom – Easy to obtain and use. Only protection against STDs. May slip off during intercourse.

IUD – Must be fitted by a doctor. Can cause heavier periods.

Hormonal Methods – Low failure rate. Side effects that may cause health problems.

Sterilisation – Very low failure rate. Not reversible.

11.12 describe the process of IVF and how it can improve the chances of pregnancy

1) It involves giving a mother FSH and LH to stimulate the maturation of several eggs.
2) The eggs are collected from the mother and are fertilised with the father’s sperm in a dish in a
laboratory.
3) The fertilised egg divides by mitosis to form an embryo.
4) The embryo is then inserted back into the surrogate mother’s uterus in order to become
pregnant.

11.13 know that genes exist in alternative forms called alleles which give rise to differences in
inherited characteristics

11.14 know the meaning of the term dominant, recessive, homozygous, heterozygous, phenotype,
genotype, co-dominance, diploid and haploid

1) Dominant – An allele that expresses a certain phenotype even in the presence of other alleles.
2) Recessive – An allele which is not expressed in the phenotype when heterozygous and is only
expressed in homozygous recessive conditions in the absence of a dominant allele.
3) Gene – A section of a DNA that codes for a particular protein.
4) Homozygous – Having two identical alleles of a particular gene.
5) Heterozygous – Having two different alleles of a particular gene.
6) Phenotype – The appearance of an organism
7) Genotype – The genetic makeup of an organism
8) Co-dominance – There are two dominant alleles for a given characteristic so both alleles are
expressed in the phenotype.
 9) Allele – An alternative form of a gene
10) Genome – All the genes in an organism
11) Recombinant – Contains genetical material from two different organisms

11.15 know that the sex of a person is controlled by one pair of chromosomes, XX in a female and XY
in a male

11.16 explain how the sex of offspring is determined at fertilisation using a genetic diagram

11.17 understand that random fertilisation produces genetic variation of offspring

11.18 understand the role of multiple alleles in the inheritance of ABO blood groups

11.19 understand patterns of monohybrid inheritance using a genetic diagram and the probabilities of
outcomes

11.20 understand how to interpret family pedigrees

11.21 describe the causes and effects of inherited conditions such as haemophilia and red-green
colour blindness (sex-linked inheritance), polydactyly (dominant allele) and cystic fibrosis (recessive
allele)

Haemophilia (Sex linked) – Recessive Allele

Cause: A gene mutation that affects the production of chemicals involved in clotting.

Effect: Clotting does not occur

Red-green colour blindness (Sex linked) – Recessive Allele

Cause: A gene mutation that affects the production of a pigment in the cones of the eye that detects
green light.

Effect: Cannot tell the difference between similar shades of green and red.

Cystic Fibrosis – Recessive Allele

Cause: A gene mutation that affects the production of mucus.

Effect: Production of thick, sticky mucus which is not easily removed by the cilia and blocks the airways.

11.22 describe how gene therapy with viruses can be used to treat cystic fibrosis (GM)

1) Gene therapy is done by having a functioning gene transferred into the DNA of the patient with a
genetic disorder.
2) A harmless virus is used as a carrier or vector for transferring the gene.
3) Another vector involved using minute droplets of lipid enclosing the gene, which were then
sprayed into the patient’s lungs
*Genetic modification

*Reverse transcription

11.23 understand that random fertilisation produces genetic variation of offspring

11.24 understand that variation within a species can be genetic, environmental or a combination of
both

Chapter 7, 8 – Respiration & Gas Exchange

8.1 know the structure of the thorax including the ribs, intercostal muscles, diaphragm, trachea,
bronchi, bronchioles, alveoli and pleural membranes

8.2 explain the role of the intercostal muscles and the diaphragm in ventilation

8.3 explain how the lungs are adapted for gas exchange by diffusion

8.4 understand the terms lung capacity, vital capacity, tidal volume and interpret spirometer traces
showing breathing movement

- Tidal Volume: The volume of air inhaled during one normal, relaxed breath.

- Vital Capacity: The maximum volume of air that can be forcefully exhaled in one breath.

- Residual Volume: The volume of air left in the lungs after a forced exhalation.

- Lung capacity: The maximum total volume of air in the lungs. (Vital capacity + residual volume)

8.5 practical: investigate the effect of exercise on the rate of breathing and measure lung capacity

 Spirometer:
1) A person breathes in and out through a mouthpiece.
1) Soda lime absorbs carbon dioxide from the exhaled air
2) The lid moves up and down.
3) A pen records the breathing movements on a rotating drum which is covered with graph paper.
4) Drum rotates at a fixed speed so the number of breaths per minute can be worked out.

 Method 2:
1) A bell jar is graduated with volume
2) Bell jar is placed open end downwards in a large bucket or sink of water.
3) Rubber bung is removed so level of water inside and outside is the same.
4) Position of bell jar is adjusted so that water level is at 0 mark.
5) Replace bung.
6) Person wears a nose clip and inhales and exhales as forcefully as they can into the tubing.
 7) New volume on scale is recorded.
8) Breathing tube needs to be sterilised before each person uses it.

8.6 describe the regulation of carbon dioxide content in the blood including the role of
chemoreceptors in the aorta and carotid arteries

1) Exercise causes a rise in CO2 in the blood.

2) Receptors in the medulla and arteries detect this.
3) Receptors send messages to the respiratory centre in the brain.
4) Respiratory centre stimulates the breathing rate to increase.
5) More CO2 passes from the blood into the lungs to be exhaled and returns the CO2 level in the
blood to be normal again.

8.7 understand the term aerobic exercise

8.8 understand the long-term benefits of exercise on the cardiovascular system

8.9 understand the pulse rate as a measure of heart rate and explain why resting pulse can be used as
a measure of physical fitness

8.10 explain why the heart rate changes during exercise and the influence of adrenaline

8.11 practical: investigate the effect of exercise on the pulse rate

1) Measure the resting pulse of a person by placing two fingers on the wrist.
2) Allow them to exercise for 5 minutes and then take the pulse rate again immediately after
exercise.
3) Repeat the experiment with people of the same age, gender and with the same type of exercise
for the same amount of time.
4) Calculate an average value for the pulse rate before and after and compare.

8.12 understand how an oxygen debt arises and how it is repaid after exercise

8.13 understand the damage to the respiratory and cardiovascular system caused by smoking

Chapter 1 – Cells & Tissues

1.1 recognise cell structures as seen with a light microscope and electron microscope (TEM images
only), including nucleus, chromosomes, cell membrane, mitochondria, endoplasmic reticulum and
ribosomes

 Light Microscope – Uses Light.

 1) Nucleus
2) Cell Membrane
3) Mitochondria
4) Cytoplasm

 Electron Microscope – Uses Electrons.

1) Nucleus
2) Mitochondria
3) Ribosomes
4) Golgi Body
5) ER

1.2 describe the functions of the cell structures: • nucleus • chromosomes • cell membrane •
mitochondria • endoplasmic reticulum • ribosomes.

1.3 describe the structure of a DNA molecule as: • two strands coiled to form a double helix •
containing nucleotides • strands linked by complementary bases • complementary bases linked by
hydrogen bonds.

1.4 describe DNA replication as the separation of DNA strands and the formation of a new strand by
complementary base pairing of nucleotides, including the role of DNA polymerase

1.5 understand that a gene is a length of DNA containing a sequence of bases that code for a specific
protein. teaching should be limited to: • the order of bases in DNA codes for the order of amino acids
in a protein • 3 bases coding for one amino acid.

1.6 know that RNA is a second type of nucleic acid that has the following features: • single stranded •
contains ribose • contains uracil and that it is used to take information from DNA in the nucleus to the
ribosomes for the synthesis of proteins.

1.7 understand that a DNA mutation involves a change in the sequence of bases that could lead to a
change in the amino acid sequence and phenotype of an individual

1.8 describe protein synthesis as: • transcription – the formation of mRNA in the nucleus • the transfer
of mRNA to ribosomes in the cytoplasm • translation of the genetic code by tRNA from mRNA codons
• the formation of a polypeptide chain using amino acids.

1.9 outline principles of genetic engineering, including:

 the production of genetically modified bacteria to produce human insulin

- The human gene for insulin production can be placed in bacteria which then produces human
insulin.

 the production of genetically modified plants to produce vaccines (e.g. hepatitis B)

 - Yeast cells can be genetically modified to produce antigens of the hepatitis B virus.
- The proteins are used to make a vaccine against hepatitis B.

 the production of genetically modified plants to improve health (e.g. Golden Rice to increase
Vitamin A in the diet)
- Using agrobacterium as a vector, scientists have produced a genetically modified rice called
‘golden rice’
- The rice has three genes added to its normal DNA content and these genes allow the rice to
make beta-carotene.
- Beta-carotene is converted into Vitamin A when eaten so it could save the eyesight of millions of
children.

1.10 understand that mitosis occurs during growth, repair, cloning and asexual reproduction

1.11 know the four main stages of mitosis; prophase, metaphase, anaphase and telophase, which
results in the production of two genetically identical diploid daughter cells

 Prophase – After DNA replication, the chromatids thicken and become visible.
 Metaphase – Chromatids line up in the middle at the equator
 Anaphase – Chromatids are pulled to opposite ends of the cell.
 Telophase- Two new nuclei forms and the cytoplasm divides to produce two genetically identical
diploid daughter cells.

1.12 know that there are different types of stem cells, including embryonic and adult stem cells that
have the ability to develop into other body cells

1.13 describe the advantages, disadvantages and ethics in the research and use of embryonic and
adult stem cells

 Embryonic Stem Cells

- Found in the early stage of embryo development
- They can differentiate into any type of cell.
- They can reproduce indefinitely in culture.
- However, they have ethical issues as it takes away a potential life.
 Adult Stem Cells
- Found in certain tissues such as the bone marrow.
- They can only differentiate into a limited range of cell types.
- They cannot reproduce indefinitely.

1.14 understand that cells are grouped into tissues and that tissues are organised into organs

1.15 describe the structure of bone, muscle (voluntary, involuntary and cardiac, as observed under a
light microscope), blood, nervous tissue and epithelium (squamous and ciliated, with reference to cells
lining the cheek and trachea)

 Voluntary Muscle (skin)

- Striated due to alignment of protein filaments in the cell.
 - Many nuclei per cell.
- Not branched
- Rapid contractions to move bones.
- Under control by the brain. (Diaphragm, Eyelash)

 Involuntary (intestine)
- Non striated because protein filaments are not aligned in the cell.
- One nucleus per cell
- Not branched
- Cell tampered at ends
- Slow, rhythmic contractions

 Cardiac (heart)
- Striated
- Many nuclei per cell
- Branched cells forming a mesh like network
- Self-excretory production
- Only present in the heart
- Constant rhythmic contractions
- Not under voluntary control

1.16 describe the structure of cells specialised for reproduction, e.g. egg (ovum) and sperm and relate
their structure to function

Chapter 6 – Nutrition & Energy

6.1 explain the importance of a balanced diet including the recommended dietary intake of
carbohydrates, fats, proteins, vitamins A and C, calcium, iron and fibre

6.2 understand variations in diet related to age, pregnancy, climate and occupation
6.3 know the sources and functions of carbohydrates, proteins, lipids (fats and oils), vitamins A, C and
D, and the mineral ions, calcium and iron

6.4 describe the causes and symptoms of deficiency diseases limited to scurvy (lack of vitamin C),
anaemia (lack of iron), blindness (lack of vitamin A) and Kwashiorkor (lack of protein)

6.5 know the structures of the human alimentary canal and describe the functions of the mouth,
oesophagus, stomach, small intestine, large intestine and pancreas in digestion

6.6 explain how food is moved through the gut by peristalsis including the role of dietary fibre in the
process

6.7 understand the role of digestive enzymes including: • their site of production and action • the
digestion of starch to glucose by amylase and maltase • the digestion of proteins to amino acids by
proteases (pepsin, trypsin) • the digestion of lipids to fatty acids and glycerol by lipases.

6.8 know that bile is produced by the liver and stored in the gall bladder and understand the role of
bile in neutralising stomach acid and emulsifying lipids

6.9 understand how the structure of the villus helps absorption of the products of digestion in the
small intestine

6.10 know the types, structure and functions of teeth, the factors that affect their growth and how to
care for teeth and gums

1) Incisors – Biting and Cutting

2) Canine – Tearing and Piercing
3) Premolars – Chewing and Grinding
4) Molars – Grinding

 Bacteria digests the glucose in the food plaque for respiration and produces acid.
 The acid attacks the enamel and causes tooth decay.

6.11 understand BMI, including the calculation of BMI, and the role of obesity as a risk factor in early
onset of diabetes and the significance of high cholesterol levels in atherosclerosis

- BMI = mass in kg / (height in metres) ^2

6.12 explain the importance of hygienic methods of food preparation, cooking, storage and
preservation

 Preventing Transmission
1) Food Preservation – slows down the rate at which microorganisms multiply
2) Cook the food properly
3) Cooked and raw foods should not be stored together
4) Foods that have been frozen and then thawed should be eaten immediately.
5) Foods should not be left in open air.
  Food Preservation
1) Salting
2) Pickling
3) Pasteurisation
4) UHT
5) Canning
6) Drying
7) Freezing
8) Irradiation

Chapter 2 – Biological Molecules

2.1 know the chemical elements present in carbohydrates, proteins and lipids (fats and oils)

2.2 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 • lipids from
fatty acids and glycerol.

2.3 describe the tests for glucose (a reducing sugar), starch, lipid and protein

2.4 practical: investigate the qualitative and quantitative content of vitamin C in food

1) Add 2cm^3 of 1% Vitamin C solution in a test tube

2) Use a 5cm^3 graduated pipette to add DCPIP solution drop by drop into the Vitamin C solution
until the DCPIP turns blue to colourless.
3) Note the volume of DCPIP solution used.
4) Repeat the experiment with 2cm^3 of lemon juice.
5) Note the volume of DCPIP solution used to turn the juice colourless.
6) 1g of 1% Vitamin C solution contains 1g per 100cm^3
7) (Vol of DCPIP added to lemon / Vol of DCPIP added to Vitamin C) x 0.01g/cm^3
8) Strong acids like lemon juice does not decolourise DCPIP completely. Instead it turns pale pink.

2.5 practical: investigate the energy content of food

2.6 explain the role of enzymes as biological catalysts in metabolic reactions

2.7 explain the action of enzymes and how their activity is affected by:

• temperature

1) As temperature increases, the kinetic energy of the molecules increases.

 2) Subsequently, the fast-moving molecules collide more frequently leading to a faster rate of
reaction.
3) Beyond optimum temperature, the enzyme’s shape changes drastically, altering the active site.
4) Thus, substrates can no longer bind to the active site which reduces rate of reaction.
5) This is called enzyme denaturation.

• pH

1) Chemical bonds holding the structure of the enzymes are weak bonds.
2) If the bonds are brown by changes in the pH, active site can be altered.
3) Small changes in the pH can affect reaction rate without denaturing the enzyme.
4) However, at an extreme pH range, the enzymes will denature.

• substrate concentration

1) Increasing substrate concentration increases rate of enzyme activity as there are more substrates
to bind to active sites.
2) However, the rate of enzyme activity will eventually plateau because all active sites will be
occupied with substrates.
3) This is called that the enzymes are saturated.

• competitive and non-competitive inhibitors.

 Competitive Inhibitors
1) Similar shape to the substrate so they can fit into the active site.
2) Temporary
3) Inhibitor does not affect the maximum rate of reaction.
4) As number of substrates increases, the reaction rate will also increase as the inhibitor will no
longer have effect.

 Non-Competitive Inhibitors
1) Do not have the shape of a substrate so cannot attach to active site.
2) Instead, it attaches to other parts of the enzyme which changes the shape of the whole enzyme
molecule including the active site.
3) Inhibitor affects the maximum rate of reaction.
4) Even as the number of substrates increases, there will be no change in the reaction because the
active site has been changed.

2.8 practical: investigate the effect of temperature and pH on enzyme activity

2.9 describe the advantages of using immobilised enzymes in: • the production of lactose-free milk •
the conversion of sucrose into glucose and fructose • glucose testing strips for diabetics.
2.10 practical: investigate the action of immobilised enzymes including the preparation of alginate
beads

1) Lactase solution is added into solution to make a mixture.

2) The mixture is then added drop by drop into 2% calcium chloride.
3) Sodium alginate turns into calcium alginate beads which contains the lactase enzymes.
4) The solution is poured into a sieve to filter the beads.
5) Pack the beads in a column and pour fresh milk into it.
6) The lactase in the beads breaks down lactose into glucose and galactose.
7) Milk leaving the column is tested for glucose.
8) Control: Milk before treatment will not contain any glucose.

Chapter 10 – Homeostatic Mechanisms

10.1 know the structure and functions of the skin and explain the role of sweat glands,
vasoconstriction, vasodilation and shivering in temperature regulation

10.2 know the definition of excretion; the removal of metabolic waste, including urea, carbon dioxide
and water

10.3 know the structure and functions of the renal system

10.4 explain why the composition of urine may vary

10.5 describe the role of the hypothalamus and pituitary gland in osmoregulation

10.6 explain the role of ADH in regulating the water content of the blood

10.7 understand the roles of insulin and glucagon in maintaining blood glucose levels

10.8 understand the concept of homeostasis and the role of negative feedback, with particular
reference to temperature control and blood glucose concentration

10.9 describe the advantages and disadvantages of: • kidney transplants • kidney dialysis.

10.10 practical: investigate diffusion using a partially-permeable membrane such as Visking tubing

10.11 describe the functions of the liver in bile production, regulation of blood sugar, urea formation
and detoxification including the breakdown of alcohol

Chapter 3 – Movement of substances in and out of the cell

3.1 know simple definitions of diffusion, osmosis and active transport

3.2 understand that movement of substances into and out of cells can be by diffusion, osmosis
(understanding of water potential is required) and active transport

3.3 understand the factors that affect the rate of movement of substances into and out of cells to
include the effects of surface area to volume ratio, temperature and concentration gradient