Structure and regulation of biochemical pathways

Question 1

Enzyme

Answer 1

A protein that acts as a biological catalyst, by speeding up reactions without being used up.

Question 2

Lock and key model

Answer 2

States that. The substrate fits into the active site like a key fits into a lock.

Question 3

Induced fit model

Answer 3

States that when a substrate binds to the active site of the enzyme, the active site can alter its shape to better fit the shape of the substrate.

Question 4

Catabolic

Answer 4

Reactions in which substrates are broken down and energy is released.

Question 5

Anabolic

Answer 5

Reactions in which larger molecules are produced from smaller substrates requiring an input of energy.

Question 6

Factors that regulate enzyme activity

Answer 6

Temperature, ph, enzyme concentration, substrate concentration, cellular compartmentalisation, inhibition of enzyme activity

Question 7

Phosphorylation

Answer 7

Binding of a phosphate group to a protein. Regulatory mechanism of protein function, (by changing the structure of enzymes).

Question 8

Cofactors

Answer 8

Components that helps enzymes catalyse a reaction.

Question 9

Coenzymes

Answer 9

Small, non-protein and organic cofactors. Eg atp.

Question 10

Reversible inhibition

Answer 10

The bonds formed between inhibitor and enzyme are weak and easily broken. Is overcome by increase in concentration of a substrate.

Question 11

Irreversible inhibition

Answer 11

Bonds formed between inhibitor and enzyme are very strong so the bonding is irreversible. Increasing substrate concentration will have no effect on this type of inhibition.

Question 12

Competitive inhibition

Answer 12

Inhibitor binds too the active site, blocking the substrate from forming a enzyme-substrate complex.

Question 13

Non-competitive inhibitor

Answer 13

Inhibitor binds to a site of the enzyme that is not the active site and changes the shape of the enzyme.