1. B3 Revision

2. Osmosis is the movement of water from a high water concentration (dilute solution) to a low water concentration (concentrated solution) through a partially permeable membrane.

3. Requires energy from the cell, which is created by respiration.
During active transport, carrier proteins in the cell membrane ‘pick up’ particles and move them against the concentration gradient.
Requires energy from the cell, which is created by respiration.

4. Ventilation is the process of breathing in and breathing out
Feature
Inhaling
Exhaling
Diaphragm
flat & contracted
domed & relaxed
Volume
increases
decreases
Ribs
up and out
down and in
Intercostal muscle
contracted
relaxed
Pressure
Lungs
inflated
deflated

6. Stomata - water Guard cells – sensitive to water and light.
TOO MUCH water – guard cells FULL, PLUMP, (TURGID)  stomata OPEN for gas exchange
TOO LITTLE water – guard cells not much water, (FLACCID),  stomata CLOSE to prevent water evaporation.
Increase in light intensity opens stomata
Decrease in light intensity closes stomata

7. Transpiration is the Evaporation of Water from Leaves

8. Light
- more light = more photosynthesis = more co2 released through stomata = more H2O lost through stomata = increased transpiration
Temperature
- More heat = more evaporation = increased transpiration
Humidity
- A lot of water vapour in air = less water loss as air already saturated with air = decreased transpiration
Wind
- Water vapour in air is replaced with drier air = water concentration in air is lower than in plant = increased transpiration

9. aorta pulmonary artery pulmonary vein valve left atrium valve
oxygenated blood to the body
pulmonary artery
pulmonary vein
valve
left atrium
valve
vena cava
tendon
right atrium
left ventricle
valve
right ventricle

10. A blood vessel which transports blood away from the heart
A blood vessel which transports blood back to the heart
A permeable blood vessel where gas exchange takes place
Red blood cell not carrying any oxygen
Red blood cell carrying oxygen
Carries deoxygenated blood from the heart to the lungs
Carries oxygenated blood from the lungs to the heart
The main blood vessel transporting deoxygenated blood to the heart
The main blood vessel transporting oxygenated blood to the body
Found in the heart and veins to ensure the blood flows in one direction

12. Artificial Heart Mechanical device to pump blood
ADVANTAGES
Temporary fix until donor heart is found
Some cases permanent therefore no need for transplant
Not rejected by body’s immune system
DISADVANTAGES
Surgery involved therefore risk of infection
Don’t work as well as natural
Can wear out
Blood flow is not as smooth therefore could get clots
Drugs to thin blood

14. Stents are metal grids which can be inserted into an artery to maintain blood flow by keeping the artery open.

15. Advantages & disadvantages of stents
No anaesthetic
Relatively cheap
Stent does not corrode
Disadvantages
Cannot open the most blocked or narrowed arteries
Can irritate the lining of the blood vessel causing scar tissue to be formed
Need to take anti-coagulant drugs

16. air sac in the lung
2 Haemoglobin and oxygen join to make oxyhaemoglobin
oxygen
3 when the blood flows past cells with very little oxygen in them the oxyhaemoglobin breaks down
1 as blood flows through the lungs the haemoglobin in the red cells picks up oxygen
4 the haemoglobin in the red cells goes back to the lungs to pick up more oxygen
oxygen diffuses into the cells of the body
oxygen is used for respiration

17. Artificial blood products
Advantages
Disadvantages
Cheap
Sides effects
Easily available
Difficult to get in to the system
Don’t need to depend on donors
May rely on blood products anyway
Good carriage of oxygen (compared to plasma or saline)
Broken down rapidly
No risk of disease
Don’t carry dissolved food
Long shelf life
Don’t clot blood
Less religious objections
Don’t offer defence against disease

19. Kidney Function Summary
1 - Filter the blood at high pressure (squeeze everything into the kidney tubule [except proteins, blood cells])
2 – Reabsorb all the glucose and amino acids by active transport
3 – reabsorb the dissolved ions (as much as the body needs)
4 – reabsorb as much water as the body needs
5 – release the urea, excess ions and excess water as urine.

20. Blood leaves the artery and enters the dialysis machine where the blood flows between partially permeable membranes.
The dialysis fluid contains the same concentration of useful substances as the blood.
Dialysis fluid contains no urea
at all so urea passes out from
the blood into the dialysis fluid
due to a steep concentration
gradient
Blood with correct conc of
dissolved substances is returned

21. Donor rejection
All your body cells have ANTIGENS (labels to say you are you!)
The donor kidney will have DIFFERENT ANTIGENS
The immune system of the person who receives the kidney could ATTACK the donor kidney.
TISSUE TYPE the kidney so its as close a match as possible
Immunosuppressant drugs given for life to reduce chance of rejection

24. Glucose – a sugar found in the body.
Glycogen – a storage of carbohydrate found in liver and muscles
Glucagon – converts glycogen into glucose.
Insulin – converts excess glucose into glycogen for storage

25. Evaluate the use of insulin injections over pancreas transplants
Insulin treatment widely available; relatively cheap
Pancreatic transplant good but surgery required; high risk; expensive; long term immunosuppressant use and most importantly not enough donors;

26. Compare modern insulin treatment with the original insulin used to treat diabetics and evaluate the two treatments
Original – from pancreases of cattle and pigs used for meat ; no control over quantities as used what was available from slaughterhouses; not genetically identical to human insulin. Some people disagree with using animal insulin (ethical/religious issues) Modern – produced by genetically modified bacteria; exact quantity and quality control; genetically identical, however some people disagree with GM insulin, long term effects unknown

27. Increased population
Non-renewable energy resources (such as coal, oil and natural gas) are being used up rapidly.
More land is being used for buildings and transport networks, quarrying, farming and dumping waste - reducing the amount of land available to other animals and plants.
More waste is being produced - causing more pollution.

28. Pollution Human activities may pollute: Water Air Land
with sewage and fertilisers (eutrophication) or toxic chemicals
Air
with smoke and gases such as sulfur dioxide which contribute to acid rain
Land
with toxic chemicals such as pesticides and herbicides, which maybe washed from the land into water

29. Deforestation
Is the cutting down of large scale forests, especially in tropical areas.
Occurs because land needed for growing biofuel crops, growing food crops (rice) and rearing cattle, buildings, wood used for timber (furniture etc…)
Causes damage because releases of CO2 when burned, less CO2 is locked away as wood, reduced biodiversity, loss of homes of indigenous people, increased methane release from rice and cattle fields.

33. Ethanol can be made by a process called fermentation
Ethanol can be made by a process called fermentation. This converts sugar into ethanol and carbon dioxide if conditions are anaerobic.
Disadvantages
Greater demand on rainforest land.
Only grows well in hot countries
Engine modification is needed
Although biofuels are in theory carbon neutral, this does not take into account the carbon dioxide emissions associated with growing, harvesting and transporting the crops, or producing the ethanol from them

34. Efficiency of food production can be improved by reducing the number of levels in the food chain

35. Animals are kept still and warm so they transfer less energy as waste heat. The energy saved can be used to produce more meat, eggs or milk.

36. FOOD MILES = The distance our food travels to get to our homes
Why do we import food from abroad
What are the problems associated with this
How can we reduce food miles
Cheaper, want out of season food, bigger profits for supermarkets, some food cannot be grown in UK
Increased fuel consumption = increased CO2 emissions = global warming
Buy British food, buy food locally, grow own food

37. Fishing quotas
Size of the holes in nets, so only bigger fish are caught.
Bans on fishing during breeding season.
Strict limit on the amount and type of fish caught.

38. What is mycoprotein?
What conditions are needed for its optimum growth?
Why is this a good food source?
Substance made from the fungi Fusarium
Aerobic conditions
High protein and low fat meat substitute ideal for vegetarians and dieters