WJEC A Level Biology
WJEC A Level Biology 3.3 Respiration Exam Questions
Free WJEC A Level Biology exam questions on 3.3 Respiration, with mark schemes. Covers glycolysis, the link reaction, the Krebs cycle, the electron transport chain and anaerobic respiration.
3.3 Respiration exam questions
1 question pack of real past exam questions with its mark scheme. Answer every question without notes, then mark your answers line by line against the mark scheme.
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WJEC A Level Biology Flashcards (Anki & Quizlet)
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Use them on Anki or Quizlet, then test yourself with the questions on this page.
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About WJEC A Level Biology 3.3 Respiration
This topic covers how energy is released from glucose. Expect stage, location and ATP yield questions.
What you need to know
- Glycolysis In the cytoplasm, glucose to two pyruvate, net 2 ATP and 2 reduced NAD.
- Link reaction and Krebs cycle In the matrix, producing CO₂, reduced NAD and FAD, and ATP.
- Electron transport chain On the cristae, using oxygen as the final electron acceptor, producing most ATP by chemiosmosis.
- Anaerobic respiration Lactate in animals and ethanol and CO₂ in yeast and plants, regenerating NAD.
Common mistakes in 3.3 Respiration
- Saying glycolysis needs oxygen.
- Mixing up where each stage takes place.
- Forgetting anaerobic respiration only yields 2 ATP.
Try three 3.3 Respiration exam-style questions
1. State where the Krebs cycle takes place. (1 mark)
Show the mark scheme answer
The mitochondrial matrix.
2. Explain the role of oxygen in aerobic respiration. (2 marks)
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It is the final electron acceptor (1), combining with electrons and protons to form water, allowing the chain to continue (1).
3. Explain why anaerobic respiration produces less ATP. (2 marks)
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Only glycolysis occurs (1), so the Krebs cycle and oxidative phosphorylation do not take place (1).
3.3 Respiration FAQs
What does Respiration cover?
All stages of aerobic and anaerobic respiration.
Which practical links here?
Investigating the rate of respiration in yeast or using a respirometer.
Can other substrates be respired?
Yes. Lipids and proteins enter the pathway at different points.
Revise this topic with flashcards: WJEC A Level Biology Flashcards, with mark scheme answers for Anki and Quizlet.
