metabolism 8.1

Question 1

Contrast metabolic chain reaction pathways with cyclical reaction pathways

Answer 1

Some are linear, for example glycolysis, and some are cyclic, for example the Krebs cycle

Question 2

Outline one example of a competitive enzyme inhibitor and one example of a noncompetitive enzyme inhibitor. ​

Answer 2

competitive: succinate to fumarate with inhibtor malonate which binds to to the enzyme.

incompetitive: troise phosphate into pyruvate with inhibtor alanine

Question 3

what is end product inhibiton?

Answer 3

when the end product of a metabollic pathway acts as a non competitive inhibitor for the initial reaction

Question 4

Illustrate end-product inhibition of the threonine to isoleucine metabolic pathway.

Answer 4

1. threonine undergoes a 5 stage reaction with the enzyme threonine dehydratase for stage 1 to form isoleucine.
2. Isoleucine will then bind to threonine dehydratase as a non competitive inhibitor.

Question 5

Outline the benefit of end-product inhibition.

Answer 5

End-product inhibition functions to ensure levels of an essential product are always tightly regulated

Question 6

State the consequence of an increase in isoleucine concentration.

Answer 6

excess production of isoleucine inhibits further synthesis

Question 7

State two methods for determining the rate of enzyme controlled reactions

Answer 7

1. The time taken for a particular substrate to be used up
2. The time taken for a specific product to be made