Enzymes


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1: How do enzymes increase the rate of a chemical reaction?
increasing the activation energy
providing the initial energy to start the reaction
increasing the chance of collisions
decreasing the activation energy
decreasing the chance of collisions
changing the equilibrium point of the reaction


2: Which of the following statements about enzymes is not true?
They are not affected by heat
They alter the rate of chemical reactions
They remain unchanged at the end of the reaction
They are made of protein
They are specific


3: Complete the word equation substrate + enzyme = products +

4:

The word equation represents a
condensation reaction
anabolic reaction
oxidation reaction
catabolic reaction
fermentation reaction


5: The temporary intermediate stage of this reaction is known as the
half time
enzyme-product complex
half reaction
enzyme-substrate complex
half life
6:

The cleft in the surface of an enzyme where the substrate fits is known as the

7: The enzyme catalase can convert hydrogen peroxide into water and oxygen molecules at the rate of
10 molecules per second
1 000 molecules per second
10 000 000 molecules per second
1 000 000 000 molecules per second


8:

Enzyme specificity is explained by which theory?

9:

amylase cellulase lipase protease) Match the correct enzyme to the statements: hydrolyses starch

10:

produces fatty acids

11:

commercially used to tenderize meat

12:

produces amino acids

13:

digests cell walls

14:

Enzymes catalyse reactions fastest at their ? temperature.

15:

Enzymes are
globular structural proteins
globular functional proteins
fibrous structural proteins
fibrous functional proteins


16: What is the optimum pH for this enzyme?

3.0
7.0
7.3
6.1-8.3
11.0


17: Which best describes the optimum range of pH for this enzyme?
3 - 11
4 - 10
5 -10
6 - 8.5
6 - 10
7
7.5


18:
Label the following statements with the correct letter to describe the rate of reaction.
Label statements not represented by the graph with an X.
Rate of reaction decreasing with increasing temperature, there are more collisions but active sites are becoming disrupted as the enzymes are denatured.
A
B
C
D
X


19: Rate of reaction decreasing with increasing temperature, there are more collisions but enzyme molecules are used up.
A
B
C
D
X


20: V max
A
B
C
D
X


21: The rate of reaction increases as the number of collisions increases.
A
B
C
D
X


22: Optimum temperature
A
B
C
D
X


23: Enzymes are completely denatured, no reactions taking place.
A
B
C
D
X


24:
Label the following statements with the correct letter to describe the rate of reaction. Label statements not represented by the graph with an X.
Rate of reaction does not increase as the enzymes are denatured.
A
B
C
X


25: Rate of reaction decreases as substrate is used up.
A
B
C
X


26: V max
A
B
C
X


27: The rate of reaction increases as substrate concentration increases. The likelihood of collisions between enzyme and substrate is increased.
A
B
C
X


28: Enzymes are completely denatured, no reactions taking place.
A
B
C
X


29:
Enzymes are completely denatured, no reactions taking place.
A
B
X


30: Relationship between enzyme concentration and initial rate of reaction is linear.
A
B
X


31: Enzyme concentration has no effect on initial rate of reaction as substrate concentration is limiting.
A
B
X


32: Use the following letters to identify the type of inhibition.
A competitive and reversible inhibition
B non-competitive and reversible inhibition
C competitive and irreversible inhibition
D non-competitive and irreversible inhibition
Inhibitor binds permanently to active site
A
B
C
D


33: Inhibitor binds temporarily to active site
A
B
C
D


34: Inhibitor binds permanently to somewhere other than the active site
A
B
C
D


35: Inhibitor binds temporarily to somewhere other than the active site
A
B
C
D



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