What is the approximate resting potential of a neurone?
From Paper 1: Biological processes
111 mark
Which cells in the islets of Langerhans secrete insulin?
From Paper 1: Biological processes
121 mark
Where does selective reabsorption of glucose mainly occur?
From Paper 1: Biological processes
131 mark
Which enzyme fixes carbon dioxide in the Calvin cycle?
From Paper 1: Biological processes
141 mark
How many ATP molecules are produced directly in the Krebs cycle per glucose?
From Paper 1: Biological processes
21(a)4 marks
Explain how summation at synapses can affect whether an action potential is produced in a postsynaptic neurone.
From Paper 1: Biological processes
21(b)3 marks
Explain why the speed of conduction in a myelinated neurone is faster than in an unmyelinated neurone.
From Paper 1: Biological processes
22(a)4 marks
Describe how insulin release is controlled by beta cells.
From Paper 1: Biological processes
22(b)3 marks
Give three advantages of producing insulin using genetically modified bacteria rather than extracting it from animals.
From Paper 1: Biological processes
23(a)4 marks
A person's kidney filters 125 cm³ of blood plasma per minute. Glucose concentration in the plasma is 1.0 mg cm⁻³. Calculate the mass of glucose filtered per day in grams, and explain why none normally appears in the urine.
From Paper 1: Biological processes
23(b)3 marks
Explain how the loop of Henle allows the production of concentrated urine.
From Paper 1: Biological processes
24(a)5 marks
Describe the role of the electron transport chain in aerobic respiration.
From Paper 1: Biological processes
24(b)*6 marks
Compare the processes of photosynthesis and aerobic respiration.
From Paper 1: Biological processes
256 marks
A student measured the rate of respiration of maggots at five temperatures using a respirometer. Suggest how she could:
(a) improve the validity of the results;
(b) process the data to show the effect of temperature;
(c) estimate the uncertainty in the volume readings.
From Paper 1: Biological processes
26(b)5 marks
Explain how the liver deals with excess amino acids.
From Paper 3: Unified biology
1(a)3 marks
Figure 1 shows the rate of oxygen uptake by germinating peas at different temperatures. Describe the trend shown.
Figure 1
From Paper 3: Unified biology
1(b)3 marks
Explain the shape of the curve.
From Paper 3: Unified biology
2(a)5 marks
Explain how the movement of water through a plant depends on water potential gradients.
From Paper 3: Unified biology
2(b)4 marks
Compare the role of osmoregulation in mammals with water conservation in plants.
From Paper 3: Unified biology
4(a)4 marks
Explain how the structure of capillaries and the formation of tissue fluid allow cells in a muscle to receive glucose during exercise.
From Paper 3: Unified biology
4(b)4 marks
Explain why muscles produce lactate during intense exercise and how this affects the body.
From Paper 3: Unified biology
6*9 marks
Discuss how the structure of proteins is related to their functions in living organisms. Use examples from different areas of biology.
From Paper 3: Unified biology
8(a)4 marks
Using an example, explain how negative feedback maintains a stable internal environment.
From Paper 3: Unified biology
8(b)3 marks
Explain why positive feedback is not usually used to maintain homeostasis, and give one example where it is useful.
Score 0 / 87 · 0 of 24 marked
This paper is written by Plasmo in the style of the OCR A-Level Biology exam. It is not a past paper and is not produced or endorsed by the exam board.
Communication, homeostasis and energy Exam Questions: OCR A-Level Biology | Plasmo