Enzymes

Question 1

What do enzymes do?

Answer 1

Speed up chemical reactions by acting as biological catalysts

Question 2

Where can enzyme action take place?

Answer 2

Intracellular

Extracellular

Question 3

What does intracellular mean?

Answer 3

Within cells

Question 4

What does extracellular mean?

Answer 4

Outside cells

Question 5

Are enzymes proteins?

Answer 5

Yes

Question 6

What do enzymes have which has a specific shape?

Answer 6

Active site

Question 7

What is the active site?

Answer 7

Part of the enzyme where the substrate molecules bind to

Question 8

Why are enzymes highly specific?

Answer 8

Due to their tertiary structure

Question 9

What is the activation energy?

Answer 9

Amount of energy that needs to be supplied to the chemicals before the reaction will start

Question 10

What is the activation energy often provided as?

Answer 10

Heat

Question 11

What do enzymes do to the activation energy?

Answer 11

Lower the amount of activation energy that is needed

So make reactions happen at a lower temperature than they could originally

So speed up the rate of reaction

Question 12

What is formed when a substrate fits into the enzyme’s active site?

Answer 12

Enzyme-substrate complex

Question 13

What are the 2 reasons why the enzyme-substrate complex lowers the activation energy?

Answer 13

2 substrate molecules need to be joined, attached to enzyme holds them closer together, reducing any repulsion between the molecules so they bond more easily

Fitting into the active site puts strain on bonds in substrate so substrate molecule breaks up more easily

Question 14

What is the ‘lock and key model’?

Answer 14

Enzyme binds to substrate if active site of enzyme is a complementary shape to the substrate

Question 15

What does the ‘induced fit’ model explain?

Answer 15

Why enzymes are so specific and only bond to one particular substrate

Question 16

What is the ‘induced fit’ model?

Answer 16

As a substrate binds, the active site changes shape slightly

Question 17

Why do enzymes only catalyse one reaction?

Answer 17

Only 1 complementary substrate will fit into the active site

Question 18

What is the enzyme’s active site determined by?

Answer 18

Enzyme’s tertiary structure

Question 19

What happens if the substrate shape doesn’t match the active site?

Answer 19

An enzyme-substrate complex won’t be formed and the reaction won’t be catalysed

Question 20

What happens if the tertiary structure of a protein is altered?

Answer 20

The shape of the active site will change

Question 21

What can the tertiary structure of an enzyme be altered by?

Answer 21

pH

Temperature

Question 22

What is the primary stricture of a protein determined by?

Answer 22

A gene