Kaplan FL 1 Flashcards BIOCHEM 2

Question 1

Find the equilibrium constant expression

Answer 1

pure solids and pure liquids are NOT part of equilibrium expression– only nitric oxide and water vapor

Question 1

what do competitive inhibitors do?

Answer 1

they INCREASE Km
Vmax satys the same

Question 2

How does competitive inhibitor look on Lineweaver Burke plot?

Answer 2

Lineweaver Burk

x intercept closer to 0 (bigger Km)
same y intercept (same Vmax)

Question 3

How does competitive inhibitor look on Michealis Menton plot?

Answer 3

V max is the same
Km increases which means more substrate is needed to reach Vmax

Km is 1/2 Vmax

Question 4

What does Lineweaver Burke plot look like

Answer 4

Question 5

What does the Michealis Menten plot look like?

Answer 5

Question 6

cooperative enzymes

Answer 6

Certain enzymes do not show the normal hyperbola when graphed on a Michaelis–Menten plot (v vs. [S]), but rather show sigmoidal (S-shaped) kinetics owing to cooperativity among substrate binding sites

Subunits and enzymes may exist in one of two states: a low-affinity tense state (T) or a high-affinity relaxed state (R). Binding of the substrate encourages the transition of other subunits from the T state to the R state, which increases the likelihood of substrate binding by these other subunits. Conversely, loss of substrate can encourage the transition from the R state to the T state, and promote dissociation of substrate from the remaining subunits.,

Question 7

example of cooperative binding enzyme in glycolysis

Answer 7

Enzymes showing cooperative kinetics are often regulatory enzymes in pathways, like phosphofructokinase-1 in glycolysis. Cooperative enzymes are also subject to activation and inhibition, both competitively and through allosteric sites.

The cooperative binding of hemoglobin, which acts as a transport protein rather than an enzyme, results in a characteristic sigmoidal binding curve that is an MCAT favorite.

Question 8

What is Hills coefficient?

Answer 8

number for the cooperativity of an enzyme

if >1, positive cooperative binding such that after one ligand is bound the affinity of the enzyme for further ligand(s) increases.

If < 1, negatively cooperative binding is occurring, such that after one ligand is bound the affinity of the enzyme for further ligand(s) decreases.

If = 1, the enzyme does not exhibit cooperative binding.