BM: Factors Affecting Enzyme Action Flashcards Preview

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Flashcards in BM: Factors Affecting Enzyme Action Deck (14)
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1
Q

What factors affect enzyme activity?

A
  • Temperature
  • pH
  • Enzyme concentration
  • Substrate concentration
2
Q

Draw a graph showing how temperature affects the rate of reaction:

A
3
Q

Draw a graph showing how pH affects enzyme action:

A
4
Q

Draw a diagram showing how enzyme concentration affects the rate of reaction:

A
5
Q

Describe the effect substrate concentration has on the rate of reaction:

A
  • Higher concentration = faster reaction
  • Saturation point is reached - active sites are ‘full’
  • If no other variables are changed, rate will fall as substrate conc. decreases with time.
6
Q

Describe the effect temperature has on enzyme-controlled reactions

A
  • As temperature increases, the kinetic energy increases. This allows more ES (enzyme-substrate) complexes to form.
  • The rate of reaction increases up to the optimum temperature
  • Once past optimum temp, bonds in the tertiary structure of the enzymes break - changing the stte of the active site
7
Q

Describe the effect pH has on enzyme-controlled reactions

A
  • All enzymes have an optimum pH
  • if the pH is below or exceeds the optimal pH, the H+ and OH- ions interfere with the ionic and hydrogen bonds in an enzymes tertiary structure.
  • This changes its shape. It is denatured and no longer works
8
Q

Describe the effect enzyme concentration has on enzyme-controlled reactions

A
  • increasing enzyme concentration will increase rate of reaction, as more enzymes will collide with substrates
  • enzyme concentration only has effect up to a certain concentration because it is no longer a limiting factor
9
Q

What are the two types of inhibition?

A

Competitive and non-competitive

10
Q

Describe competitive inhibition:

A
  • Inhibitor molecules have similar shape to substrate molecules.
  • Compete with substrate molecules to bind to active site.
  • No reaction occurs, but they block active site.
11
Q

What happens if there is a high concentration of inhibitor molecules relative to substrate molecules?

A

Inhibitor wil ltake up nearly all of active sites.

12
Q

Describe non-competitive inhibition:

A
  • Inhibitor molecules bind to allosteric site.
  • Active site changes shape so substrate can no longer bind to it.
13
Q

What happens if substrate concentration is increased during competitive inhibition?

A

Rate will increase as substrates have an increased chance of reaching active site before inhibitor.

14
Q

What happens if substrate concentration is increased during non- competitive inhibition?

A

Reaction rate will stay the same - enxyme activity will still be inhibited.

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