FOM 2.1.2

Question 1

What is the equilibrium constant for the reaction A+B —> C+D

Answer 1

Keq= [products]/[reactants] [C][D]/[A][B]

Question 2

What is the equation for Gibbs free energy?

Answer 2

deltaG = deltaH- TdeltaS

Question 3

What does a negative delta G indicate?

Answer 3

A reaction is spontaneous and will proceed in the forward direction

Question 4

What does a positive delta G indicate?

Answer 4

A reaction is non-spontaneous and will favor the reverse reaction

Question 5

Will the products or reactants have a higher concentration at equilibrium if the delta G is negative?

Answer 5

Products

Question 6

Will the products or reactants have a higher concentration at equilibrium if the delta G is positive?

Answer 6

Reactants

Question 7

What factors influence velocity and how?

Answer 7

Energy - higher energy will have more velocity such as in temperature Reduced spacing - increases the concentration, same products in less space

Question 8

How are thermodynamics and kinetics related?

Answer 8

The keq for a given reaction is indicated by the concentration of the products over the reaction. This is influenced by the standard free energy change which will influence if the products or reactants are favored and by how much

Question 9

A person inhales an anthrax toxin and now is experiencing very high fever. If the protein causing the fever is stable at higher temps what can be said about the k value of this protein?

Answer 9

The Kforward value will be a larger number because at higher temps the reaction will speed up

Question 10

What is a steady state?

Answer 10

If the variables that define the system are unchanged over time. The same number of people throwing ping-pong balls across the court (may not have the same amount of balls on the sides of the court, but the amount of people throwing them is the same)

Question 11

What is transient state?

Answer 11

The conditions that exist at the beginning of a system could be all factors equal eachother. Same amount of ping pong balls on either side of the court

Question 12

Over the course of a day/night cycle what is more likely to exist in a steady state: The number of glucose derived from food or the number of glucose inside a cell.

Answer 12

The number of glucose that are inside a cell. Food is going to get broken down and have variable peaks of glucose created during times of eating. Cells are always working hard to keep the cellular concentration of glucose consistent.

Question 13

Is proteolysis a reversible or irreversible?

Answer 13

Irreversible because it involves the breaking of the polypeptide backbone

Question 14

What are the general properties of a catalyst?

Answer 14

Specific - for the reaction they speed up They are unchanged by the reaction No change in equilibrium ONLY change the rates at which the forward or reverse reaction occurs

Question 15

How do catalysts tend to help in the in speeding up a reaction?

Answer 15

By lowering the activation energy of a certain reaction

Question 16

Glucose metabolism requires many enzymatic steps, what is the outcome of the overall reaction in regards to K values and free energies?

Answer 16

The k forward value is larger and there is no change in the Keq or the standard free energy

Question 17

How is an enzyme changed over the course of a reaction?

Answer 17

An enzyme may change over the course of a reaction, but it will always return to its initial state.

Question 18

What are the advantages of a catalyst?

Answer 18

Lower activation energy for a reaction, tend to stabilize the transition state, specificity (differentiate between similar chemicals), drive reactions forward at “gentle” reaction conditions, controlled releases of energy

Question 19

Can you explain how an unfavorable reaction can be coupled with a favorable reaction do drive an unfavorable reaction forward? Use; M+N O+P as the unfavorable and use: O+Z OZ as the favorable

Answer 19

In the first reaction M+N, though it is the unfavorable reaction, is going to create small amounts of O+P. Once the O and P are created the O is going to immediately react with the Z and form the complex of OZ. The first reaction is then going to want to compensate for the lost O and drive the reaction forward and thus creating more P

Question 20

What is the most common way enzymes drive a reaction forward that is not favored?

Answer 20

ATP hydrolysis by an enzyme is the most often used

Question 21

What is equilibrium

Answer 21

The concentrations of all species are constant with time

Question 22

What are the two schools of thought for specificity of a ligand binding to an enzyme?

Answer 22

The lock and key model vs the induced fit model

Question 23

Explain the transient state vs steady state vs equilibrium

Answer 23