3.2.2 bioenergetics

Question 1

Futile Cycle

Answer 1

when two metabolic pathways run simultaneously in opposite directions and have no overall effect other than to dissipate energy in the form of heat.

example: Glucose going back and forth from Glucose to G6P which helps with rapid response for up/downregulation

Question 2

Near Equilibrium Reaction

Answer 2

• reaction goes back and forth
• example Creatine Kinase in muscles facilitate ATP being made by Phosphocreatine then being used by muscle (preworkout drink)

Question 3

Essentially Irreversible

Answer 3

• products are so favored it’s essentially going one direction.
• In metabolism, equilibrium never reached so it basically won’t work backwards.
• Ex: azide modification of heme– the protein will likely be degraded before the azide dissociates

Question 4

State Function

Answer 4

• delta G

- Independent of path

Question 5

Equilibrium constant

Answer 5

Keq: magic ratio of products and reactant at equilibrium, the ratio the reaction is working towards
-Changing chemical nature of substrate or product will change this ratio

Question 6

standard free energy

Answer 6

ΔG˚ = −RT ln K; this is derived at equilibrium when ΔG = 0 because potential energy is 0 at equilibrium. On the graph, it the vertical line that the reaction is working towards.

Question 7

Oxidizing Agent:

Answer 7

-Drives reduction by accepting electrons (NAD+—> NADH)

Question 8

Reducing Agent

Answer 8

-Reducing agent loses electrons via oxidation (Glyceraldehyde 3-P—–>1,3-Bisphosphoglycerate)

Question 9

How does our body avoid equilibrium (death)?

Answer 9

-adding substrate (food) and removing product (CO2)

Question 10

What enzyme can convert AMP + ATP to 2 molecules of ADP?

Answer 10

Adenylate Kinase

Question 11

Free energy is independent of_____ and dependent on _______

Answer 11

enzyme; substrate