B M 5 : Factors Affextingn Enzyme Activity Flashcards Preview

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Flashcards in B M 5 : Factors Affextingn Enzyme Activity Deck (26):
1

What two things affect an enzymes activity?

Temperature and pH

2

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

It increases

3

What happens to the enzyme molecules as temperature increases?

They vibrate more

4

What happens if temperature goes above a certain level?

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

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

5

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

Enzyme is denatured
-no longer functions as a catalyst

6

What’s the optimum temperature?

The temperature the enzyme denatures after

7

For human enzymes what’s the optimum temp?

37

8

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

60

9

What do all enzymes have?

An optimum pH value

10

What do most human enzymes work best at for pH

7

11

What pH does pepsin work best at?

Acidic pH 2
- as fond in stomach

12

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

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

13

What affect enzyme rate of reaction?

-Enzyme concentration

-Substrate concentration (up to a point)

14

How enzyme concentration affects rate of reaction?

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

15

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

- enzyme has no further affect

16

How does substrate concentration affect rate of reaction?

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

17

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

It decreases if no further substrate is added

18

What can prevent enzyme activity

Enzyme inhibitors

19

What are enzymes inhibitors?

Molecule that binds to enzyme that they inhibit

20

What two things can inhibitors be?

-competitive

OR

-non-competitive

21

Shape of competitive inhibitors?

Similar shape to the substrate molecule

22

What do competitive inhibitors do

Compete with substrate molecules to bind to the active site, but no reaction takes place
-
They block the active site

23

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

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

24

What if there’s a high substrate concentration?

The substrates chances of getting an active site before inhibitor increases

-so increase concentration of substrate increase rate of reaction

25

What do non-competitive inhibitors do?

Bind to the enzyme away from its active site
-causes active site to change shape

26

Does increases the concentration of substrate affect non competitive inhibitors ?

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