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Practice · Biology · 2025 syllabus · C1.1

IB Biology C1.1 Enzymes and metabolism: practice questions

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

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

Classifying metabolic reactions

Which row correctly describes the metabolic reaction? [1]

  1. Synthesis of glycogen in liver cells: catabolic, glycosidic bonds broken by hydrolysis
  2. Digestion of protein in the stomach: anabolic, peptide bonds formed by condensation
  3. Hydrolysis of lactose by lactase: anabolic, a glycosidic bond is broken
  4. Synthesis of a polypeptide at a ribosome: anabolic, peptide bonds formed by condensation
Show the answer and the reasoning

Answer: D. D is correct. Building a polypeptide joins monomers into a macromolecule, so it is anabolic, and each peptide bond forms by condensation with the release of water. A names an anabolic process but calls it catabolic: glycogen synthesis forms glycosidic bonds by condensation. B is the reverse of what happens: digestion breaks peptide bonds by hydrolysis, which is catabolic. C gets the bond right but the category wrong, because splitting a larger molecule into smaller ones is catabolism. In a row question, check every column: one right column does not make a right row.

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The 5 questions in C1.1

  1. C1.1-01 Classifying metabolic reactionsPaper 1A style · multiple choice · 1 mark
  2. C1.1-02 Activation energy from a graphPaper 1A style · multiple choice · 1 mark
  3. C1.1-03 Two inhibitors comparedPaper 1A style · multiple choice · 1 mark · HL
  4. C1.1-04 pH and two digestive proteasesPaper 2 style · short answer · 7 marks
  5. C1.1-05 Catalase rate from gas volumesPaper 1B style · data-based · 10 marks

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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.