B2.1.4e) Cofactors, coenzymes and prosthetic groups

Question 1

Cofactors

Answer 1

Molecules that increase the rate of reaction or are required for enzyme function
(Usually inorganic molecules or ions)

Question 2

Cofactors function

Answer 2

They help proteins
Many transfer atoms from 1 reaction to another (eg. iron or zinc)
Form part of the active site

Question 3

Coenzymes

Answer 3

Molecules that help enzymes function
(Usually organic molecules)

Question 4

Coenzymes function

Answer 4

Work with enzymes
Many coenzymes are derived from vitamins (eg. fruit & vegetables)
Sit at the active site of an enzyme & aid in recognising, attracting or repulsing a substrate or product
A temporary feature of the enzyme
Binds loosely to enzymes

Question 5

Carbonic anhydrase

Answer 5

Zinc containing enzymes
Catalyse the reversible reaction between CO2 hydration & bicarbonate hydration
Found in red blood cells
H2O + CO2 ↔ H+ + HCO3-

Question 6

Cl-

Answer 6

Needed to activate amylase (coenzyme)

Question 7

NAD

Answer 7

Activates enzyme alcohol dehydrogenase
Binds to allosteric site & changes the shape of the active site so the substrate can fit

Question 8

Prosthetic groups

Answer 8

Cofactors that are tightly bound to an enzyme

Question 9

Enzyme activation

Answer 9

Coagulation cascade
Platelets migrate to place of injury
Fibrin ‘mesh-work’- help to clot blood
Prothrombin → thrombin
(factor x)
Fibrinogen → fibrin
(thrombin)