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Enzymes
5 Class 9 Biology questions with answers and explanations.
Printable worksheet with answer key
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Enzymes are made of:
- 1 Proteins
- 2 Carbohydrates
- 3 Lipids
- 4 Nucleic acids only
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Correct answer: Proteins
Enzymes are protein molecules that act as biological catalysts.
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The substance on which an enzyme acts is called the:
- 1 Substrate
- 2 Inhibitor
- 3 Product
- 4 Coenzyme
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Correct answer: Substrate
The enzyme binds to its substrate and converts it into products.
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Most human enzymes work best at about:
- 1 37 degrees C
- 2 0 degrees C
- 3 100 degrees C
- 4 70 degrees C
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Correct answer: 37 degrees C
Human body temperature is about 37 degrees C, which suits most human enzymes.
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At a very high temperature, an enzyme:
- 1 Turns into a carbohydrate
- 2 Works faster forever
- 3 Is denatured and stops working
- 4 Becomes a substrate
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Correct answer: Is denatured and stops working
High heat changes the enzyme's shape so it can no longer fit its substrate.
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The lock and key model explains:
- 1 How cells divide
- 2 How plants make food
- 3 How enzymes fit their specific substrates
- 4 How blood circulates
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Correct answer: How enzymes fit their specific substrates
The active site of an enzyme fits its own substrate like a key in a lock.