Energy transfers: Respiration

From Mock A · Paper 2 (topics 5–8)

2.12 marks

Give the net products of glycolysis for each molecule of glucose.

From Mock A · Paper 2 (topics 5–8)

2.22 marks

Explain why oxygen is needed for oxidative phosphorylation.

From Mock A · Paper 2 (topics 5–8)

2.32 marks

Germinating seeds produced 0.70 cm³ of CO₂ and used 0.98 cm³ of O₂ in the same time. Calculate the respiratory quotient and suggest which respiratory substrate was being used.

From Mock A · Paper 2 (topics 5–8)

2.44 marks

In a respirometer containing germinating seeds and potassium hydroxide solution, a coloured liquid moved 25 mm along a capillary tube of radius 0.5 mm in 10 minutes. (a) Explain why the liquid moved towards the seeds. (b) Calculate the rate of oxygen uptake in mm³ min⁻¹. Volume = πr²l.

Investigation: temperature and respiration in yeast

A student added yeast suspension to glucose solution in a water bath and collected the carbon dioxide produced over 5 minutes. Each temperature was repeated five times.

Temperature / °C	20	30	40	50
Mean volume of CO₂ / cm³	1.2	2.6	4.9	1.1
Standard deviation / cm³	0.2	0.3	0.9	0.4

From Mock A · Paper 3 (all topics, practical skills and essay)

1.11 mark

Calculate the mean rate of CO₂ production at 40 °C in cm³ min⁻¹.

From Mock A · Paper 3 (all topics, practical skills and essay)

1.22 marks

Explain the increase in the volume of CO₂ produced between 20 °C and 40 °C.

From Mock A · Paper 3 (all topics, practical skills and essay)

1.32 marks

Explain the result at 50 °C.

From Mock A · Paper 3 (all topics, practical skills and essay)

1.82 marks

Yeast can respire anaerobically. Explain how anaerobic respiration allows glycolysis to continue.

From Mock B · Paper 2 (topics 5–8)

2.13 marks

Describe the link reaction.

From Mock B · Paper 2 (topics 5–8)

2.22 marks

How many molecules of reduced NAD are produced in the Krebs cycle from one molecule of glucose? Explain your answer.

From Mock B · Paper 2 (topics 5–8)

2.32 marks

Explain why anaerobic respiration produces much less ATP per glucose than aerobic respiration.

From Mock B · Paper 3 (all topics, practical skills and essay)

725 marks

Write an essay on ONE of the following topics. EITHER The importance of membranes in living organisms. OR The ways in which organisms use energy released from ATP. You should select and use information from different parts of the specification.

From Mock C · Paper 2 (topics 5–8)

2.13 marks

Describe oxidative phosphorylation.

From Mock C · Paper 2 (topics 5–8)

2.22 marks

The respiratory quotient (RQ) of germinating castor oil seeds is 0.7. What does this suggest? Explain.

From Mock C · Paper 2 (topics 5–8)

2.32 marks

Explain why production of lactate allows glycolysis to continue in anaerobic conditions.

Score 0 / 56 · 0 of 15 marked

This paper is written by Plasmo in the style of the AQA A-Level Biology exam. It is not a past paper and is not produced or endorsed by the exam board.