Enzyme action
5.1What the syllabus asks of you
- Describe a catalyst as a substance that increases the rate of a chemical reaction and is not changed by the reaction
- Describe enzymes as proteins that function as biological catalysts and are involved in all metabolic reactions
- Explain enzyme action with reference to the substrate, active site, enzyme-substrate complex, and product
- Explain the specificity of enzymes in terms of the complementary shape and fit of the active site with the substrate (‘lock and key’ hypothesis)
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Chapter 5: Enzyme action
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Every question on Enzyme action, untimed, marked as you go.
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5 questions
1May / June 2020 · Paper 11 · Q4Show mark scheme →
AAll enzymes are proteins.
BEnzymes are inactive at very low temperatures.
CHuman enzymes are most active just below 40 °C.
DMost enzymes can catalyse only one reaction.
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2May / June 2020 · Paper 12 · Q4Show mark scheme →
Achlorophyll
Bfibrinogen
Cinsulin
Dlipase
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3Oct / Nov 2019 · Paper 11 · Q4Show mark scheme →
AEnzymes are made of lipid molecules and change the rate of a reaction.
BEnzymes are permanently denatured by high and low temperatures.
CEnzymes can only operate within a living organism.
DEnzymes have individual shapes that lock onto specific molecules.
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4Oct / Nov 2019 · Paper 12 · Q4Show mark scheme →
AIt can no longer fit the substrate molecules.
BIt can now catalyse several different reactions.
CIt has become part of the product molecules.
DIt is available to catalyse the same reaction again.
Mark scheme
5May / June 2019 · Paper 11 · Q4Show mark scheme →
AAll enzymes are made of protein.
BEnzymes are biological catalysts.
CEnzymes are destroyed during the reaction they are involved in.
DMost human enzymes work best at temperatures between 35 °C and 40 °C.
Mark scheme