IB Biology HL C1.1.15 Hl Competitive Inhibition Questions
Practise IB Biology HL 1.1.15 by applying competitive inhibition concepts to exam questions.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Exam points
- Explain that a competitive inhibitor resembles the substrate and binds reversibly to the enzyme active site, preventing substrate binding.
- Interpret rate-versus-substrate evidence to identify competitive inhibition and explain why increasing substrate concentration reduces its effect.
- Distinguish competitive from non-competitive inhibition using binding location, reversibility and substrate-response evidence.
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IB Biology HL C1.1.15 Hl Competitive Inhibition Questions question 1
[Maximum number: 4]
Interactions in biological systems may have harmful or beneficial effects.
Explain, using an example, how competitive inhibitors interfere with enzyme activity.
a. binds to the active site / inhibitor is complementary to the active site;
b. prevent binding of substrate (so reducing enzyme activity/rate of reaction) OR
fewer enzyme-substrate complexes form;
c. inhibitor chemically similar/similar in shape/similar in structure to substrate
d. statins are competitive inhibitors of HMG-CoA reductase/enzyme needed to make cholesterol;
e. statins prevent conversion of HMG-CoA to mevalonate;
Marking guidance:
Accept other examples for mark point d and mark point e such as:
Oxygen binds to rubisco (d.) and preventing production of glycerate 3-phosphate (e.)
Malonate binds to succinic dehydrogenase (d.), preventing production of fumarate (e.).
Allow penicillin as a competitive inhibitor of transpeptidase/for bacterial cell wall production for mark point d, but not mark point e.
4
max
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