These are SOME common exam questions that have come up on unit 1 biology AQA AS past papers from all the june series.


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  • Created on: 07-01-13 20:19

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1. Explain why the solution used was
(i) ice-cold
Reduce/prevent enzyme activity
Prevents osmosis / no (net) movement of water;
So organelle/named organelle does not burst/shrivel
2. People with mitochondrial disease have mitochondria that do not function properly.
Some people with mitochondrial disease can only exercise for a short time. Explain
why a person with mitochondrial disease can only exercise for a short time
(Mitochondria) use aerobic respiration;
Mitochondria produce ATP/release energy;
Energy/ATP required for muscles (to contract
3. Sino atrial node (SAN) is in the right atrium of the heart. Describe the role of the SAN node.
Sends out electrical activity/ impulses;
Initiates the heartbeat / acts as a pacemaker / (stimulates)
contraction of atria
4. A glucose biosensor detects only glucose. Use your knowledge of the way in which
enzymes work to explain why
Enzyme/active site has a (specific) tertiary structure;
Only glucose has correct shape / is complementary / will bind/fit;
To active site;
(Forming) enzyme-substrate complex;
5. Give two ways in which pathogens can cause disease when they enter the body of their host.
Damage/destruction of cells/tissues;
Production of toxins;
6. What is a vaccine?
Contains antigen/proteins / dead/weakened
Stimulates production of antibodies/plasma cells/memory
7. Explain why the antibodies used in this test must be monoclonal antibodies
All have same shape / only binds to Giardia/one type
of/specific antigen;

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Destruction of phagocytes (lines 4­5) causes the lungs to be more susceptible to
infections. Explain why
Phagocytes engulf/ingest pathogens/microorganisms/bacteria/viruses
Phagocytes destroy pathogens/microorganisms/bacteria/viruses
Lung diseases are caused by pathogens/microorganisms/bacteria/viruses
9. The reduced elasticity of the lungs (lines 6­7) causes breathing difficulty. Explain how?
Alveoli/lungs will not inflate/deflate fully/reduced lung capacity;
Breathing out particularly affected/no longer passive;
Concentration/diffusion gradient / rate of diffusion reduced
10.…read more

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Explain why the scientists
3 (d) (i) homogenised the tissue
Breaks open cells / disrupts cell membrane / releases cell contents / releases organelles /
break up cells;
3 (d) (ii) filtered the resulting suspension
Removes (cell) debris / complete cells / tissue;
3 (d) (iii) kept the suspension ice cold during the process
Reduces / prevents enzyme activity;
3 (d) (iv) used isotonic solution during the process
Prevents osmosis / no (net) movement of water / water does not enter organelle / water
does…read more

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Active transport requires energy / ATP;
7 Ref. to Na+ / glucose co-transport;
18. Describe and explain how the lungs are adapted to allow rapid exchange of oxygen
between air in the alveoli and blood in the capillaries around them.…read more

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Explain how atheroma can lead to a heart attack
1. Coronary artery / vessel is blocked/narrows;
2. Restricts oxygen supply to heart muscle / cells / tissue;
3. Prevents respiration / ATP production / or (heart) muscle / tissues/cells die;
24. After an infection with chlamydia, cells of the immune system of the mice may attack
the heart muscle cells (lines 7-8). Explain why.
1. Antibodies/memory cells against chlamydia (protein/antigen) are present;
2. Protein on heart (muscle) similar to chlamydia protein/antigen;
3.…read more


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