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Enzymes
Class 11 · Biology · 8 questions
Name: ____________________ Date: ____________
An enzyme lowers the:
- A Substrate mass
- B Activation energy
- C Temperature
- D Product mass
A competitive inhibitor:
- A Increases the rate
- B Binds elsewhere on the enzyme
- C Is a substrate
- D Binds to the active site
The optimum pH of pepsin is about:
- A 9
- B 7
- C 2
- D 12
A non protein part that helps an enzyme to work is a:
- A Product
- B Cofactor
- C Hormone
- D Substrate
Increasing substrate concentration increases the rate of an enzyme reaction until:
- A The product stops forming
- B The temperature falls
- C All enzyme active sites are occupied
- D The pH rises
The part of an enzyme where the substrate binds is the:
- A Cofactor
- B Allosteric site only
- C Active site
- D Coenzyme
Enzymes work best at:
- A Very high temperature
- B Their optimum pH and temperature
- C Any pH
- D Very low pH
Which of these is not true about enzymes?
- A They are specific
- B They are proteins
- C They are used up in reactions
- D They lower activation energy
Answer key
1. B, 2. D, 3. C, 4. B, 5. C, 6. C, 7. B, 8. C
Enzymes speed up reactions by lowering the activation energy.
It competes with the substrate for the active site.
Pepsin works in the acidic stomach.
Cofactors and coenzymes are needed by many enzymes.
At saturation, adding more substrate gives no increase.
The active site has the shape that fits the substrate.
Each enzyme has its own optimum.
Enzymes are not used up.