Enzymes

Question 1

Define an enzyme

Answer 1

A protein biological catalyst that speeds up the rate of reaction by lowering activation energy

Question 2

Define a substrate

Answer 2

The substance an enzyme acts on

Question 3

Define activation energy

Answer 3

The energy required to start a reaction

Question 4

Describe the active site of an enzyme

Answer 4

The active site is complementary and specific to the substrate in terms of shape and charge.

Question 5

Compare a chemical catalyst and biological catalyst

Answer 5

Both increase the rate of reaction by lowering activation energy
A biological catalyst is always made of protein while a chemical catalyst is not

Question 6

Name an enzyme found in the mouth

Answer 6

amylase

Question 7

State four factors that affect enzyme activity

Answer 7

Temperature
pH
Concentration
Surface area to Volume ratio

Question 8

Describe what happens to an enzyme when temperature is too high / enzyme is outside optimal pH range

Answer 8

Denature. This means that the active site of the enzyme changes shape and is no longer specific and complementary to the substrate

Question 9

What is the scaffold for a describe question?

Answer 9

(Key term) this means that ….

Question 10

What is the scaffold for an explain question?

Answer 10

Because…
Then….
Therefore….

Question 11

What is an independent variable?

Answer 11

The factor that is changed in an experiment to determine its effect on the dependent variable

Question 12

What is a Dependent variable?

Answer 12

Something that is measured to determine if the independent variable has had any effect (always a state a time)

Question 13

What is a controlled variable?

Answer 13

A factor that is kept constant throughout the experiment, so it is not having an effect on the dependent variable

Question 14

How can you improve reliability in an experiment?

Answer 14

Repeat the experiment many times.

Question 15

Explain how a temperature much lower than the optimum will affect an enzyme controlled reaction

Answer 15

Because the kinetic energy is low
then there will not be many successfull collisions between enzyme and substrate
therefore not many enzyme-substrate complexes form and not much product forms and the rate of reaction is low.

Question 16

Explain how a pH much higher than the optimum will affect an enzyme controlled reaction

Answer 16

Because the enzymes denature
then the active site is no longer specific and complementary to the substrate and there will not be many successfull collisions between enzyme and substrate
therefore not many enzyme-substrate complexes form and not much product is formed and the rate of reaction is low.