(LE 2) Enzymes and Energy

Question 1

What is enzyme activity? What is it influenced by?

Answer 1

Rate at which substrate is converted into product

• temperature
• pH
• substrate and enzyme concentration
• cofactor and coenzyme concentration
• stimulatory or inhibitory effects of products on enzyme function

Question 2

How is enzyme activity used clinically?

Answer 2

amount of enzyme in a sample can be based on the rate of product synthesis. Abnormally high plasma concentrations of certain enzymes are indicative of disease

Question 3

What is the function of a cofactor and coenzyme?

Answer 3

Cofactors: typically metal ions. used to help change shape of enzyme

coenzymes: derived from vitamins; transport small molecules needed by enzymes

Question 4

Are enzymes always active? If not, how are enzymes activated and deactivated?

Answer 4

No
activated by phosphorylation and inactivated by dephosphorylation

Question 5

What determines the direction in which the reaction is catalyzed by the enzyme?

Answer 5

Law of mass action: reactiion happens high side to low side

Question 6

What are the first and second laws of thermodynamics?

Answer 6

1. energy cannot be created or destroyed, only changed
2. energy is lost with each transformation through heat