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Practice · Biology · 2025 syllabus · C1.2

IB Biology C1.2 Cell respiration: practice questions

6 exam-style questions on C1.2 Cell respiration, SL and HL, 3 marked HL: 3 multiple choice, 1 data-based, 1 short answer and 1 extended response. Each one comes with the mark scheme, a model answer and the reasoning behind every mark. Free with your email.

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C1.2-01 · Paper 1A style · multiple choice · 1 mark

Anaerobic respiration in muscle

Which row describes anaerobic cell respiration in human muscle? [1]

  1. Oxygen needed: no; mitochondria needed: no; product: lactate
  2. Oxygen needed: no; mitochondria needed: yes; product: lactate
  3. Oxygen needed: no; mitochondria needed: no; products: ethanol and CO2
  4. Oxygen needed: yes; mitochondria needed: no; product: lactate
Show the answer and the reasoning

Answer: A. A is correct. Anaerobic respiration in humans takes place in the cytoplasm without oxygen: glucose is broken down to pyruvate, which is converted to lactate. B is wrong because mitochondria are needed only for the aerobic stages (link reaction, Krebs cycle, electron transport chain). C gives the products of anaerobic respiration in yeast, not humans. D contradicts the meaning of anaerobic: no oxygen is used.

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The 6 questions in C1.2

  1. C1.2-01 Anaerobic respiration in musclePaper 1A style · multiple choice · 1 mark
  2. C1.2-02 Respirometers with and without alkaliPaper 1A style · multiple choice · 1 mark
  3. C1.2-03 Counting reactions after glycolysisPaper 1A style · multiple choice · 1 mark · HL
  4. C1.2-04 Regenerating NAD without oxygenPaper 2 style · short answer · 8 marks · HL
  5. C1.2-05 Yeast respiration on different sugarsPaper 1B style · data-based · 9 marks
  6. C1.2-06 Energy transfer to ATPPaper 2 style · extended response · 15 marks · HL

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Every Biology and Chemistry question here is original, written for practice in the style of the papers set since the 2025 syllabus, with invented data. Developed independently from the International Baccalaureate Organization, which has not endorsed it. Found a mistake? Email vytis@limeadmissions.com with the question id.