2.4 enzymes

Question 1

What type of protein are enzymes?

Answer 1

Globular proteins

Question 2

Are enzymes soluble? Why?

Answer 2

• yes

* due to the presence of many hydrophilic side groups

Question 3

What are enzymes necessary for?

Answer 3

Building up large polymer based components which make cells, which make tissues, which make organs, which make organ systems

Question 4

How many enzymes are there?

Answer 4

Thousands

Question 5

What is the difference between each enzyme?

Answer 5

Each one is specific for a specific reaction, as each has a specific active site to fit a specific substrate

Question 6

What sort of reactions do enzymes catalyse?

Answer 6

Anabolic and catabolic reactions

Question 7

What are anabolic reactions?

Answer 7

Reactions that build something up

Question 8

What are catabolic reactions?

Answer 8

Reactions that break something down

Question 9

What type of reactions are catalysed by enzymes?

Answer 9

Both anabolic and catabolic reactions

Question 10

In catabolic reactions where is energy released from?

Answer 10

Large organic molecules such as glucose

Question 11

Where do anabolic reactions get energy from in order to occur?

Answer 11

Catabolic reactions

Question 12

What are anabolic reactions necessary for?

Answer 12

Building up and growing

Question 13

Define METABOLISM:

Answer 13

The sum of all the different reactions and reaction pathways happening in all organisms

Question 14

Why can metabolism happen?

Answer 14

Due to the control and order imposed by enzymes

Question 15

What part of the enzyme is involved in catalysis?

Answer 15

The active site

Question 16

What is enzyme shape determined by?

Answer 16

The sequence of amino acids in its structure and the bonds between the atoms in that structure

Question 17

Why do different types of enzymes have different shapes and functions?

Answer 17

Because the order and type of amino acids in their structure is different

Question 18

What is enzyme specificity?

Answer 18

Only substrate with the exact shape to fit in the active site will bond to the enzyme and react

Question 19

What are enzymes?

Answer 19

Biochemical catalysts that speed up reactions without being used up

Question 20

What do molecules in solution do?

Answer 20

Move and collide randomly

Question 21

For a reaction to occur what do molecules need to do?

Answer 21

Collide in the right orientation

Question 22

What is activation energy?

Answer 22

The amount of energy that needs to be supplied to the chemicals/reactants before a reaction will start

Question 23

How is activation energy often supplied?

Answer 23

As heat

Question 24

What role do enzymes play with reference to activation energy?

Answer 24

They reduce the activation energy needed to make a reaction happen
• lowering temperature
• speeding up the rate of reaction

Question 25

What formation lowers activation energy?

Answer 25

The formation of the enzyme substrate complex

Question 26

Why does the formation of the enzyme substrate complex, lower activation energy, in a reaction where substrate is joining?

Answer 26

• two substrate molecules joining
• attaching to the enzyme holds them close together
• reduces repulsion
• molecules bond more easily

Question 27

Why does the formation of the enzyme substrate complex, lower activation energy, in a reaction where the enzyme is catalysing a breakdown?

Answer 27

• breakdown reaction
• fitting into the active sites puts strain on the bonds in the substrate
• substrate molecules break up more easily

Question 28

What does the lock and key model say?

Answer 28

In the same way only the right key will fit into a lock only a specific substrate will fit the active site of the enzyme

Question 29

How does the lock and key model work?

Answer 29

• substrate enters
• substrate binds to active site
• enzyme substrate complex forms
• products form in enzyme products complex
• products released
• enzyme left unchanged

Question 30

What does the induced fit hypothesis say?

Answer 30

Recent research suggests the active site of the enzyme changes shape slightly as the substrate enters

Question 31

How does the induced fit hypothesis work?

Answer 31

• substrate enters
• as substrate hinds active site changes shape slightly
• enzyme substrate complex formed
• enzyme product complex formed
• products released