Introduction To Enzymes

Question 1

What do organisms need to carry out to survive?

Answer 1

Metabolic reactions

Question 2

What does metabolism refer to?

Answer 2

Refers to all the reactions of the body

Question 3

Why do the metabolic reactions need to happen quickly?

Answer 3

So that organisms can respond to these changes in their environment

Question 4

What 2 ways can you speed up the reaction?

Answer 4

Increasing temperature

Use a catalyst

Question 5

Why is increasing temperature a bad way to speed up reactions?

(3)

Answer 5

Higher temperatures can damage cells

• they can melt lipids
• they can denature proteins

Question 6

Increasing temperature

What happens when proteins are denatured?

(2)

Answer 6

Loose shape

Can’t function

Question 7

What is a catalyst?

Answer 7

A chemical that speeds up the rate of reaction and remains unchanged and reusable at the end of the reaction

Question 8

What are biological catalyst for metabolic reactions called?

Answer 8

Enzymes

Question 9

What do cells use to carry out metabolic reactions quickly?

Answer 9

Use proteins called enzymes

Question 10

What is a substrate?

Answer 10

A molecule that can have a reaction catalysed by an enzyme

Question 11

What is the enzymes turnover number?

Answer 11

The number of substrates an enzyme can catalyse in one minute

Question 12

What do substrates bind to?

Answer 12

The reactive part of an enzyme called its active site

Question 13

What must be right for a substrate to bind with an active site?

Answer 13

The right shape

Question 14

What will every substrate have that it can bind with?

Answer 14

A specific enzyme

Question 15

What does complementary binding refer to?

Answer 15

Refers to when 2 molecules fit together to complete each other

Question 16

What effects an enzymes ability to function?

Answer 16

The 3D shape of its active site

Question 17

What factors can the shape of the active site be affected by?

Answer 17

pH

Temperature

The presence of inhibitors or cofactors

Question 18

What is activation energy?

Answer 18

The (kinetic) energy required at the start of a reaction

Question 19

What type of energy do molecules need to move?

Answer 19

Kinetic energy

Question 20

What needs to happen for a chemical reaction to occur?

Answer 20

The right molecules need to collide with sufficient energy

Question 21

What can cause more ‘successful’ collisions?

Answer 21

If more molecules have enough kinetic energy to react then there will me more ‘successful’ collisions

Question 22

Will a reaction with a lower activation energy occur faster or slower?

Answer 22

Faster

Question 23

Why will a reaction with a lower activation energy occur faster?

Answer 23

Because there will be more molecules with sufficient energy to react

Question 24

How do enzymes catalyse reactions?

What do they also allow to occur?

Answer 24

By lowering the activation energy required for a reaction to occur

They also allow reactions to occur at lover temperatures

Question 25

What must happen for enzymes to catalyse a reaction?

Answer 25

A substrate needs to bind to its active site

Question 26

How to most metabolic reactions occur?

Answer 26

In a series of small steps

Question 27

What do active sites contain?

What do they do?

Answer 27

They contain reactive molecules

That can carry out these small steps in a controlled way with lower activation energy

Question 28

What happens when a substrate binds to the active site?

Answer 28

It’s held in a specific orientation that facilitates its reaction

Question 29

What type of pressure can the active site apply to a substrate?

Answer 29

Physical pressure

Which further lowers the activation energy