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Edexcel A-Level Biology AS 2.7 Enzyme Action and Specificity Questions

Identify active-site complementarity, link R-group bonding to three-dimensional enzyme shape, and explain how inhibitors, temperature and substrate concentration alter catalysis and rate.

Syllabus
First assessment 2019
Course
Biology YBI11
Level
AS

Exam points

  • Explain enzyme specificity through active-site shape, R groups, substrate complementarity and enzyme–substrate complexes.
  • Explain catalysis through activation-energy reduction and relate inhibitor, temperature or pH effects to active-site change.
  • Interpret enzyme-rate evidence and apply enzyme mechanisms to biological, industrial or metabolic contexts.

Edexcel A-Level Biology AS 2.7 Enzyme Action and Specificity Questions question 1

[Maximum number: 1]

The photograph shows a species of fungus growing on a dead tree in a woodland habitat.

Figure for Question Edexcel A-Level Biology AS 2.7 Enzyme Action and Specificity Questions question 1 — Edexcel A-Level Biology AS

© www.pqpictures.co.uk / Alamy Stock Photo Wood contains a high proportion of lignin and cellulose. Fungi can break down molecules in wood by releasing extracellular enzymes.

Different species of fungus can break down different molecules in wood. The effect of two species of fungus on the percentage loss in mass of wooden blocks was investigated. Species A was grown on one set of wood blocks and species B was grown on another set of wood blocks. The percentage loss in mass of the blocks was recorded every four weeks. The graph shows the results of the investigation.

Figure for Question Edexcel A-Level Biology AS 2.7 Enzyme Action and Specificity Questions question 1 — Edexcel A-Level Biology AS

Suggest one reason for the difference in breakdown of the wood by species A and species B.

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