B M 5 : Factors Affextingn Enzyme Activity

Question 1

What two things affect an enzymes activity?

Answer 1

Temperature and pH

Question 2

What happens to the rate of an enzyme- controlled reaction when temperature increases

Answer 2

It increases

Question 3

What happens to the enzyme molecules as temperature increases?

Answer 3

They vibrate more

Question 4

What happens if temperature goes above a certain level?

Answer 4

Vibration breaks some of the bonds that hold the enzyme in shape

• so active site changes shape and enzyme + substrate no longer fit together

Question 5

What does it mean when an enzyme and substrate no longer fit?

Answer 5

Enzyme is denatured

-no longer functions as a catalyst

Question 6

What’s the optimum temperature?

Answer 6

The temperature the enzyme denatures after

Question 7

For human enzymes what’s the optimum temp?

Answer 7

37

Question 8

For biological washing powder enzymes what’s the optimum temperature?

Answer 8

60

Question 9

What do all enzymes have?

Answer 9

An optimum pH value

Question 10

What do most human enzymes work best at for pH

Answer 10

7

Question 11

What pH does pepsin work best at?

Answer 11

Acidic pH 2

- as fond in stomach

Question 12

Above or below the optimum pH how can it affect enzymes?

Answer 12

The H+ and H- ions found in acids and alkalis can mess up Ionic and hydrogen bonds that hold enzymes tertiary structure in place
- changes enzymes active site shape so enzyme is denatured

Question 13

What affect enzyme rate of reaction?

Answer 13

• Enzyme concentration

- Substrate concentration (up to a point)

Question 14

How enzyme concentration affects rate of reaction?

Answer 14

-more enzyme molecules there is in solution, the more likely a substrate molecule will collide with one and form an enzyme substrate complex

Question 15

What happens if the amount of substrate is limited in an increase in enzyme concentration?

Answer 15

• enzyme has no further affect

Question 16

How does substrate concentration affect rate of reaction?

Answer 16

• more substrate molecules means a collision between substrate + enzyme is more likely and so more active sites used

Question 17

As substrate concentration decreases what happens to the rate of reaction?

Answer 17

It decreases if no further substrate is added

Question 18

What can prevent enzyme activity

Answer 18

Enzyme inhibitors

Question 19

What are enzymes inhibitors?

Answer 19

Molecule that binds to enzyme that they inhibit

Question 20

What two things can inhibitors be?

Answer 20

-competitive

OR

-non-competitive

Question 21

Shape of competitive inhibitors?

Answer 21

Similar shape to the substrate molecule

Question 22

What do competitive inhibitors do

Answer 22

They block the active site

Question 23

How much the competitive enzyme inhibits the enzyme depends on what?

Answer 23

The relative concentrations of the inhibitor and substrate

• if high concentration of inhibitor will take up nearly all active site and hardly any substrate gets to enzyme

Question 24

What if there’s a high substrate concentration?

Answer 24

The substrates chances of getting an active site before inhibitor increases

-so increase concentration of substrate increase rate of reaction

Question 25

What do non-competitive inhibitors do?

Answer 25

Bind to the enzyme away from its active site

-causes active site to change shape

Question 26

Does increases the concentration of substrate affect non competitive inhibitors ?

Answer 26

No - rate of reaction won’t be affected as enzyme inhibitor doesn’t compete