2.4 Factors Affecting Enzyme Activity Flashcards

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1
Q

Name 4 factors affecting enzyme activity:

A
  • temperature
  • PH
  • enzyme concentration
  • substrate concentration
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2
Q

What happens to the rate of reaction when temperature increases?

A

Rate of reaction increases

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3
Q

What does more heat provide the molecules with?

A

More kinetic energy

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4
Q

If the molecules have more KE what happens?

A

The molecules move faster

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5
Q

The faster the molecules (substrate) move what is more likely to occur?

A

collisions with enzymes, meaning there is more chance of a reaction

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6
Q

What does a rise in temperature do to enzyme molecules?

A

Makes them vibrate more

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7
Q

What happens with the vibrations if the temperature goes above a certain level?

A

The vibrations break some of the bonds that are holding the enzymes shape

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8
Q

What happens to the enzyme if bonds holding its shape are broken?

A
  • active site changes shape
  • substrate no longer fits
  • enzyme is denatured
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9
Q

What is optimum temperature?

A

The temperature at which an enzyme works best (rate of reaction is highest)

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10
Q

What is the optimum temperature for most human enzymes?

A

37°c

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11
Q

At what ph do most human enzymes work best at?

A

PH7

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12
Q

What PH does pepsin work best at? Why is this useful?

A
  • PH 2 (acidic)

* useful as it is found in the stomach

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13
Q

What happens to the H+ and OH- ions found in acids and alkalis above and below optimum PH?

A

• they can mess up the ionic and hydrogen bonds holding the enzymes tertiary structure in place

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14
Q

What does a change in the enzymes tertiary structure cause?

A

Change in the shape of the active site

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15
Q

What happens if the active site changes shape?

A
  • enzyme and substrate no longer fit

* enzyme is denatured

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16
Q

What is more likely to happen the higher the enzyme concentration?

A

Collisions with substrate and the formation of enzyme-substrate complexes

17
Q

What effect does increasing substrate concentration have on the rate of reaction?

A

• increased substrate concentration means increased rate of reaction

18
Q

If the amount of substrate is limited what effect does increasing enzyme concentration have? Why?

A
  • No effect

* because there is more than enough enzymes to deal with the available substrate

19
Q

The higher the substrate concentration…?

A

The faster the rate of reaction

20
Q

Why does increased substrate concentration mean increased rate of reaction?

A

There are more substrate molecules increasing the chance of collision between enzyme and substrate

21
Q

What happens to the rate of reaction if you add more substrate after the saturation point?

A

• no effect on the rate of reaction

22
Q

Why is there no effect on the rate of reaction when adding more substrate after the saturation point?

A
  • too many substrate molecules

* all the enzymes active sites are full

23
Q

How can you measure the rate of enzyme controlled reactions?

A
  • speed of appearance of product

* the speed of disappearance of substrate

24
Q

Give an example of an experiment for measuring the speed of product appearance?

A
  • catalase catalysing the break down of hydrogen peroxide to oxygen and water
  • collecting the oxygen produced whilst measuring how fast it is given off
25
Q

Give an example of an experiment used to measure the disappearance of substrate?

A
  • amylase catalysing the breakdown of starch to maltose
  • detect starch using potassium iodide and iodine solution
  • time how long it takes the starch to disappear