8.5 Enzyme Activity

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8.5 Enzyme Activity

• 8.5.1 Enzyme Action

LO I understand how enzymes work.
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The molecule that an enzyme acts upon is called
the .
substrate

• The substrate must fit into the site
  on the enzyme before the reaction to take place.

active
If the is too high or the
is wrong, the enzyme will change .
temperature
pH
shape
It becomes and stops working.
denatured
LO I understand how enzymes work.
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8.5.2 The Effect of pH

• LO I understand how pH affects the activity of
  an enzyme.

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Catalase is an enzyme that catalyses the
breakdown of hydrogen peroxide in living cells.
hydrogen peroxide
oxygen
water

• Experiment

LO I understand how pH affects the activity of
an enzyme.
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The activity of the enzyme can be measured by
counting the number of oxygen bubbles produced in
3 minutes

• Results

pH Number of Bubbles
1 0
4 6
7 28
10 63
13 45
LO I understand how pH affects the activity of
an enzyme.
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Graph

• Number of O2 bubbles

pH
Conclusion
The activity of the enzyme increases with pH to
an optimum at pH 10 and decreases thereafter.
LO I understand how pH affects the activity of
an enzyme.
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8.5.3 The Effect of Temperature

• LO I understand how temperature affects the
  activity of an enzyme.

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The activity increases with temperature to an
optimum at 40C and thereafter decreases.

• Results

Number of O2 bubbles
Temperature (C)
Conclusion
LO I understand how temperature affects the
activity of an enzyme.