Intro to Biochemistry Day 5 quiz

What is the main function of enzymes?

To speed up chemical reactions by lowering the activation energy

Do enzymes change the ΔG of a reaction?

No enzymes do not affect the free energy (ΔG)

change of a reaction

What is the transition state in a reaction?

It is a high energy intermediate where bonds are partially formed/broken; enzymes stabilize this state

What is the equation for Gibbs’s Free Energy?

ΔG = ΔH-TΔS

What does a negative ΔG mean?

that the reaction is spontaneous and favored to happen.

What does a positive ΔG mean?

the reaction is non-spontaneous and requires energy input

What is coupling in bioenergetics?

a combination of non-spontaneous and spontaneous reactions to push a process forward.

What is allosteric regulation

when a molecule binds at a site other than the active site, changing enzyme activity

What is covalent regulation?

Enzyme activity is modifed by adding or removing chemical groups (ex. phosphorylation)

What is sequestration?

when enzymes are isolated in a compartment to control timing of activity.

What is a zymogen?

An inactive enzyme that gets activated by cleavage.

Give an example of a zymogen.

pepsinogen is activated to pepsin in the stomach.

What are enzyme inhibitors?

Molecules that decrease enzyme activity; reversible or irreversible