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Enzymes
5 Class 11 Biology questions with answers and explanations.
Printable worksheet with answer key
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An enzyme lowers the:
- 1 Substrate mass
- 2 Activation energy
- 3 Temperature
- 4 Product mass
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Correct answer: Activation energy
Enzymes speed up reactions by lowering the activation energy.
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A competitive inhibitor:
- 1 Increases the rate
- 2 Binds elsewhere on the enzyme
- 3 Is a substrate
- 4 Binds to the active site
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Correct answer: Binds to the active site
It competes with the substrate for the active site.
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The optimum pH of pepsin is about:
- 1 9
- 2 7
- 3 2
- 4 12
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A non protein part that helps an enzyme to work is a:
- 1 Product
- 2 Cofactor
- 3 Hormone
- 4 Substrate
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Correct answer: Cofactor
Cofactors and coenzymes are needed by many enzymes.
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Increasing substrate concentration increases the rate of an enzyme reaction until:
- 1 The product stops forming
- 2 The temperature falls
- 3 All enzyme active sites are occupied
- 4 The pH rises
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Correct answer: All enzyme active sites are occupied
At saturation, adding more substrate gives no increase.