Factors Affecting Enzyme Action

Question 1

State 4 main Factors that affect enzyme action

Answer 1

1. Temperature
2. pH levels
3. Enzyme concentration
4. Substrate concentration

Question 2

What is Denaturing?

Answer 2

When active site of an enzyme changes shape. Enzyme cannot perform it’s function now as it is non complementary to substrate. Denaturing is permanent.

Question 3

What is the optimum

Answer 3

The preferred/best environment for an enzyme to perform it’s function

Question 4

Describe shape of graph of enzyme action vs temperature

Answer 4

Assymetrical graph that gradually rises to optimum and then steeply drops

Question 5

Describe enzyme action before optimum temperature

Answer 5

As temperature increases, so does enzyme action.
This is because kinetic energy increases, so enzymes and substrate collide more frequently, resulting in more product in a given time. Rate of reaction is increases.

Question 6

Describe enzyme action at the optimum temperature

Answer 6

At optimum temperature there are the most number of collisions per second between enzymes and substrate. Rate of reaction is highest.

Question 7

Describe enzyme action after optimum temperature

Answer 7

When temperature increases past optimum, enzyme action drops.
Kinetic energy is too high, causing enzymes to denature. This means active site changes shape, and so substrate is not complementary to active site. Less/no products formed. Rate of reaction decreases.

Question 8

Describe how enzymes may be inactivated using temperature

Answer 8

By reducing temperature to extremely low points below optimum. Enzymes can be stored this way.

Question 9

Describe shape of graph of enzyme action vs pH levels

Answer 9

Symmetrical graph that steeply drops before and after optimum

Question 10

What is pH?

Answer 10

Measure of Acidity (presence of positive hydrogen ions) and alkalinity (presence of negative Hydroxide)

Question 11

Describe enzyme action before optimum pH

Answer 11

For pH below optimum, enzyme denatures due to increase in H+. This breaks bonds in active site, causing enzyme to denature (change in shape of active site). Substrate is no longer complementary and so rate of reaction slows/stops.

Question 12

Describe enzyme action after optimum pH

Answer 12

For pH above optimum, enzyme denatures due to increase in OH-. This breaks bonds in active site, causing enzyme to denature (change in shape of active site). Substrate is no longer complementary and so rate of reaction slows/stops.

Question 13

Describe enzyme action during optimum pH level

Answer 13

Proportion of H+ and OH- is correct to maintain bonds within active site of enzyme. Active site will be complementary to substrate and rate of reaction will be high.

Question 14

Describe shape of graph for Enzyme Action vs enzyme/substrate concentration

Answer 14

Graph rises towards Vmax, and then plateaus

Question 15

What is the Vmax?

Answer 15

Represents highest rate of reaction, which cannot be surpassed

Question 16

What does concentration of substrate/enzyme refer to

Answer 16

Amount of substrate/enzyme

Question 17

Describe Enzyme Action before Vmax for increase in substrate concentration

Answer 17

As we increase substrate concentration, the rate increases because there are increasing number of substrate molecules which are converted into product by enzymes.

Question 18

Describe Enzyme Action after Vmax for increase in substrate concentration

Answer 18

At particular [sub], the rate reaches a maximum where increasing [sub] past this point has no effect on rate. All active sites are occupied by substrate at any given time already.

Question 19

Describe Enzyme action before Vmax for increase in enzyme concentration

Answer 19

With no, or very few enzymes, very little substrate is converted to product at a given time because there are very few active sites. Rate increases as [enz] rises.

Question 20

Describe Enzyme action after Vmax for increase in enzyme concentration

Answer 20

At Vmax, no further increase in rate can be achieved because there is excess enzymes with many unoccupied active sites.