2.1.4

Question 1

What are enzymes?

Answer 1

Biological catalysts that speed up the metabolic reactions

Question 2

What happened to the enzymes at the end of the reaction?

Answer 2

Nothing they remain unchanged so can be used again

Question 3

How do you enzymes increase the reaction rate?

Answer 3

By lowering its activation energy

Question 4

What are intracellular enzymes?

Answer 4

Enzymes act within cells

Question 5

What type of enzyme is catalase and what does it do?

Answer 5

Intracellular

Quickly breaks down hydrogen peroxide into water and oxygen

Question 6

What are extracellular enzymes?

Answer 6

Enzymes that act outside the cell that made them.

Question 7

What form of nutrients in and how are they dealt with?

Answer 7

Polymer form: proteins/polysaccharides

They are broken down into smaller components first then absorbed through cell membrane

Question 8

What is the role of extracellular enzymes?

Answer 8

They are released from cells to break down large nutrient molecules e.g. indigestion

Question 9

Extracellular enzymes and single celled organisms, how do they work?

Answer 9

They release enzymes into immediate environment to break down polymers needed for nutrition

Question 10

How do you enzymes work in multicellular organisms?

Answer 10

The large molecules need to be digested so that they can be absorbed into the bloodstream and transported around and used as substrate in cellular reactions

Question 11

What enzymes are used for human digestion?

Answer 11

Amylase and trypsin

Question 12

What is the structure of enzymes?

Answer 12

They are globular proteins

Question 13

What is anabolic reactions?

Answer 13

Building up a molecule (synthesis)

Question 14

What is catabolic reaction?

Answer 14

Breaking down a molecule
Hydrolytic reaction (produces water and enzyme substrate complex)

Question 15

What is metabolism?

Answer 15

Combination of anabolic and catabolic reactions

Question 16

What metabolic pathway?

Answer 16

Sequence of enzyme controlled reactions

Question 17

What is the mechanism of enzyme action?

Answer 17

Reactions happen when molecules occur in rights orientation

Speed increases, more collisions, more successful collisions, reaction rate will increase

Question 18

What is specificity?

Answer 18

How one enzyme catalyse one biochemical reaction

Question 19

What Is activation energy?

Answer 19

Energy needed to be supplied for most reactions to start

Question 20

What do R groups in enzymes do?

Answer 20

Interact with substrate to make temporary bonds,

Putting strain on bonds within substrate therefore helping the reaction along

Question 21

What is the induced fit hypothesis?

Answer 21

Initial interaction between enzyme and substrate is weak
These interactions rapidly induced changes in tertiary structure
Strengthening binding and putting strain on molecule
Therefore bonds in substrate weaken so the activation energy decreases

Question 22

What affect does temperature have on the rate of reaction?

Answer 22

Temperature increases, increase in kinetic energy, faster movement, more collisions, more successful collisions
Faster rate of reaction

Question 23

What happens when there is too much heat?

Answer 23

Bonds break, so the tertiary structure changes and so will the active site denaturing the enzyme

Question 24

What effect does PH have on rates of reaction?

Answer 24

Low pH means acidity bricks bond is causing enzyme to be denatured
High PH means alkalinity breaks bonds causing denaturation

Question 25

What affect the substrate concentration have on the rate of reaction?

Answer 25

Low means low rate as there is less chance of successful collisions
High means higher rate as there is more chance of successful collisions

Question 26

What are cofactors?

Answer 26

Non-protein-helper-component

Transfer atoms or groups of atoms from one reaction to another in multistep pathway

Question 27

What are co-enzymes?

Answer 27

Organic molecules derived from vitamins.

Question 28

How do you coenzymes work?

Answer 28

Briefly find with or two active sites before or simultaneously with substrate.

Question 29

What may happen to the enzyme because of a co-enzyme?

Answer 29

Maybe changed so can’t be reused (chemically changed)

Question 30

Cofactors can be:

Answer 30

• Loosely or temporarily bound

- tightly bound and form a more permanent feature of enzyme

Question 31

Describe what happens using carbonic anhydrase

Answer 31

It’s the enzyme needed for metabolism of CO2.
CO2 and H2O move into red blood cells and combine with carbonic acid.
Carbonic anhydrase catalyses this reaction.

Question 32

What do you enzyme inhibitors do?

Answer 32

Inactivate enzymes by:-preventing them from catalysing

-slowing them down

Question 33

What is competitive inhibition?

Answer 33

Molecule or part of molecule that fits into the active site.
Blocks the substrate
So it competes with the substrate to bind to active site.

Question 34

What impact do you competitive inhibitors have on enzymes?

Answer 34

Reduce the rate of reaction but doesn’t change V-max

Question 35

As an inhibitor what does aspirin do?

Answer 35

It inhibits COX enzymes, preventing chemicals responsible for producing pain fever being synthesised

Question 36

What is non-competitive inhibition?

Answer 36

Molecule or part of molecule binds to allosteric site.

Causes enzymes tertiary structure to change and so the active site changes.

Question 37

What is the allosteric site?

Answer 37

Location other than the active site

Question 38

What affect does non-competitive inhibition have on the rate of reaction?

Answer 38

Reduces the rate of reaction as more active sites becomes unavailable

Question 39

What are irreversible inhibitors?

Answer 39

Inhibitors that cant be removed (often toxic)

Question 40

What is end product inhibition?

Answer 40

When product of reaction acts as an inhibitor to the enzyme that produces it.

Question 41

What type of inhibition is end product inhibition?

Answer 41

Non compétitive réversible inhibition

Question 42

Describe the two steps of respiration making ATP

Answer 42

-Addition of two phosphate groups to glucose molecule
-addition of second phosphate group results in initial breakdown of glucose.
The breakdown of glucose is catalysed by phosphofructokinase (inhibited by atp)