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IB Biology HL C1.1 Enzymes and Metabolism Questions

Practise IB Biology HL C1.1 by explaining enzyme specificity, metabolic reactions, rate evidence, inhibition and feedback control in biological pathways.

Syllabus
First assessment 2025
Course
Biology HL
Level
HL

Exam points

  • Explain enzyme catalysis through activation-energy reduction and relate active-site specificity to substrate binding and induced fit.
  • Interpret metabolic pathways and classify enzyme-controlled reactions, including condensation, hydrolysis and oxidation, as anabolic or catabolic.
  • Explain how tertiary-structure and active-site changes affect enzyme binding and activity.
  • Interpret enzyme-rate graphs and data for temperature, pH, substrate concentration, optima and saturation; evaluate assay reliability.
  • Interpret enzyme energy profiles to identify reduced activation energy without a change in reactant or product energy.
  • Distinguish intracellular and extracellular enzymes using digestive-enzyme examples and pepsinogen activation.
  • Relate basal metabolic rate and heat production to climate, body mass and surface-area-to-volume ratio.
  • Distinguish linear from cyclical metabolic pathways by whether an intermediate is regenerated.
  • Compare competitive and non-competitive inhibition using binding site and substrate-response evidence.
  • Explain feedback inhibition by end-product binding to an earlier pathway enzyme, including isoleucine synthesis.

Covered syllabus points

C1.1.1—Enzymes as catalystsC1.1.2—Role in metabolismC1.1.3—Anabolic and catabolic reactionsC1.1.4—Enzymes as globular proteinsC1.1.5—Induced-fit bindingC1.1.6—Molecular motionC1.1.7—Relationships between structure and functionC1.1.8—Effects on enzyme activityC1.1.9—Measuring enzyme reactionsC1.1.10—Effect of enzymes on activation energyC1.1.11 (HL)—Intracellular vs. extracellular enzymesC1.1.12 (HL)—Heat generationC1.1.13 (HL)—Cyclical and linear pathways in metabolismC1.1.14 (HL)—Allosteric sites and non-competitive inhibitionC1.1.15 (HL)—Competitive inhibitionC1.1.16 (HL)—Feedback inhibitionC1.1.17 (HL)—Mechanism-based inhibition

Question 1

[Maximum number: 4]

Outline the action of enzymes.

Question 2

[Maximum number: 6]

Question (a)

(a)

Identify the following processes as either anabolism or catabolism by placing a tick ( ✓ ) in the correct box.

Table for Question (a) — IB Biology HL
[ 2 ]

Question (b)

(b)

Outline the importance of enzymes to metabolic processes.

[ 4 ]

Question 3

[Maximum number: 1]

What is an example of anabolism?

A

Formation of peptides after protein digestion

B

Formation of glucose and fructose from sucrose

C

Formation of maltose from two glucose molecules

D

Formation of glycerol and fatty acids from triglycerides

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