Enzymes

Question 1

Enzyme

Answer 1

globular protein which acts as a biological catalyst by speeding up the rate of a chemical reaction

Question 2

Enzymes reusable

Answer 2

Enzymes are reusable since they are not changed or consumed by the reactions they catalyse

Question 3

Active site

Answer 3

The active site is the region on the surface of the enzyme which binds to the substrate molecule. The active site and the substrate complement each other in terms of shape and chemical properties

Question 4

Enzyme reactions

Answer 4

Enzyme reactions typically occur in aqueous solutions (ex. cytoplasm). Therefore in most cases the enzyme and substrate move in the active site. exception is if they are membrane bound

Question 5

Enzyme Catalysis

Answer 5

Enzyme catalysis requires that the substrate be brought into close physical proximity with the active site.
When a substrate binds to the enzyme’s active site, an enzyme-substrate complex is formed
The enzyme catalyses the conversion of the substrate into product, creating an enzyme-product complex
The enzyme and product then dissociate – as the enzyme was not consumed, it can continue to catalyse further reactions

Question 6

Collision frequency

Answer 6

the rate of enzyme catalysis can be increased by imporoving the frequency of collisions via:
- increasing molecular motion of of the particles
- increasing the concentration of particles

Question 7

Binding site

Answer 7

All enzymes have a cavity to which the substrate can bind with high specificity, this is called the active site

Question 8

Denaturation of Enzyme

Answer 8

Functioning enzyme with complementary active site -> Denatured enzyme with incompatible active site

Question 9

factors affecting activity of Enzymes

Answer 9

1) temperature - low temp. results in insufficient thermal energy for the activation of an enzyme catalysed reaction to process
increasing the temp. will increase higher enzyme activity
2) PH - changing the PH will alter the charge of the enzyme, which will in turn alter protein solubility and overall shape
3) substrate concentration - increasing substrate conc. will increase the activity of a corresponding enzyme, however after some time the environment is saturated and the rate stays the same

Question 10

immobilised enzymes in industry use

Answer 10

• Biofuels
• Medicine
• Biotechnology
• food production
• Textiles
• Paper

Question 11

Lactose

Answer 11

Lactose is a disaccharide of glucose and galactose which can be broken down by enzyme lactase

Question 12

Producing Lactose free milk

Answer 12

Lactose-free milk can be produced by treating the milk with the enzyme lactase

Question 13

Advantages of Lactose-Free Dairy Products

Answer 13

can be used in a variety of ways:
- As a source of dairy for lactose-intolerant individuals
- As a means of increasing sweetness in the absence of artificial sweeteners
- As a way of reducing the crystallisation of ice-creams
- As a means of reducing production time for cheeses and yogurts