Enzyme Kinetics and Thermodynamics

Question 1

What is Catabolism (exergonic reactions)?

Answer 1

It is a reaction that breaks down complex molecules into simple ones. Which releases energy

An example is Glucose breakdown to Pyruvate

Question 2

What is Anabolism (endergonic reactions)?

Answer 2

Reaction that synthesis (build up) of complex molecules from simple ones. Which requires energy

An example is Peptide synthesis from amino acids

Question 3

What is a Important enzyme for induced fit?

Answer 3

Hexokinase

Question 4

What is the Lineweaver-Burke Plot?

Answer 4

The inverse of the reaction rate is plotted against the inverse of the substrate concentration

Question 5

What is the Eadie Hofstee Plot?

Answer 5

The rate of reaction is plotted as a function of the ratio between rate and substrate concentration

Question 6

What is the Michaelis constant?

Answer 6

The concentration of a given substrate which catalyses the associated reaction at half the maximum rate - Km

Question 7

What does each symbol mean for Michaelis constant?

Answer 7

V = rate of reaction
Vmax = maximal rate of reaction at saturation substrates concentration
[S] = substrate concentration
Km = Michaelis constant, also reflects the affinity of the substrate for the enzyme

Question 8

In terms of Km with Enzyme substrates?

Answer 8

Small Km = STRONG bonding of substrate to enzyme
High Km = WEAK bonding of substrate to enzyme

Question 9

In terms of Vmax with Enzyme substrates?

Answer 9

Vmax = maximum velocity or max rate of rxn –>
enzyme in working at full capacity –>
every active site has substrate bound to it

Question 10

Describe the Zero Law of thermodynamics?

Answer 10

If the ‘body’ A is in thermal equilibrium with the ‘body’ B, and the ‘body’ B is in thermal equilibrium with ‘body’ C. Then the ‘body’ A and the ‘body’ C are also in thermal equilibrium.

Question 11

What is the 1st Law of Thermodynamics?

Answer 11

The internal energy of an isolated system is constant

Question 12

What is the 2nd Law of Thermodynamics?

Answer 12

The entropy of an isolated system increases for any spontaneous change

Question 13

What is the 3rd Law of Thermodynamics?

Answer 13

The entropy, S, of a perfect crystal at the absolute zero of the temperature scale is zero

Question 14

What is internal energy and equation?

Answer 14

U is the total energy contained within a system
ΔU = w + q

w = work and q = heat

Question 15

What is enthalpy and equation?

Answer 15

The sum of internal energy and the product of the pressure and volume of thermodynamics system.

ΔU = ΔH - PΔV

Question 16

What is entropy and equation?

Answer 16

Entropy, S, can be considered as a measure of disorder. Entropy is a state function

For reversible input of heat into a system:
ΔS = q/T

Where heat is not transferred reversibly:
ΔS > q/T

If ΔS = q/T at a constant pressure = ΔH = q

Question 17

What is Gibbs free energy and equation?

Answer 17

The balancing effect between Enthalpy and Entropy is expressed in the change

ΔG = ΔH - TΔS

Question 18

What is heat capacity and equation?

Answer 18

Represented by C and measured in Joules per gram per kelvin

Cp = ΔH/ΔT
Cv = ΔU/ΔT

Question 19

What is Spontaneous?

Answer 19

Occurs naturally. A spontaneous change does not require input of work for it to come about. This does NOT necessarily mean that the process is rapid.

Question 20

What is Non-Spontaneous?

Answer 20

Requires work in order to be brought about spontaneity arises from a natural tendency for disorder. It does NOT ARISE, however from a tendency towards lower energy.

Question 21

What is the Equilibrium constant and equation?

Answer 21

K is the value of the reaction quotient

At equilibrium, ΔG = 0, and Q = K therefore:
ΔG = -RTInk

R = 8.314 JK-1 mol-1

Question 22

What do you add to temperature to change to K?

Answer 22

273.15