Exam 2 Flashcards
(193 cards)
The minimum amount of energy required to bring about a chemical reaction is called:
Activation energy
Which of the following is not a property of enzymes?
A) Capable of being regulated
B) Reaction rates high in comparison to uncatalyzed reaction
C) Highly specific
D) Side products of reactions are rare
E) All of the above are true
All of the above are true
Consider the following reaction diagram. Which letter indicates the transition state?

C
In contrast to inorganic catalysts, enzymes have an intricately shaped surface called the __________.
Active Site. Each active site is a cleft or crevice in a large protein molecule into which substrate molecules can bind in a catalysis-promoting orientation.
The lock and key model of enzyme activity proposes that each:
Enzyme binds a specific substrate because the active site and substrate have complementary structures.
The synthesis of enzymes in response to changing metabolic needs is referred to as:
Enzyme induction, allows cells to respond efficiently to changes in their enviorment.
Which of the following is a coenzyme?
NADP+ (complex organic molecule
Alcohol dehydrogenase without NAD+ is called a _______:
Apoenzyme (The protein component of an enzyme that lacks an essential cofactor)
The term synthetase is included in which class of enzymes?
Ligases
Which of the following is not a type of oxidoreductase?
A Peroxidase
B) Hydroxylase
C) Reductase
D) Dehydrogenase
E) Peptidase
Peptidase
Which of the following classes of enzymes catalyze reactions involving the cleavage of bonds by the addition of water?
Hydrolase
Consider the following reaction data.
Alanylanine + water —–à alanine
[alanylanine} [water] Rate
- 1 0.1 1x 10-4
- 2 0.1 2x10-4
- 1 0.2 2x10-4
- 2 0.2 4x10-4
The reaction is _______ order overall.
Second
The steady state assumption states that if:

K1 = the rate constant for ES formation
K2 = the rate constant for ES dissociation
K3 = the rate constant for product formation
The rate of formation of ES is equal to the rate of its degradation over the course of the reaction
The expression of the Michaelis constant is equal to:
Where
K1 = the rate constant for ES formation
K2 = the rate constant for ES dissociation
K3 = the rate constant for product formation

km=(K2 + K3)/K1
Specific activity is defined as
The number of I.U. per mg of protein (quantity used to measure enzyme purification)
In the Lineweaver-Burk double reciprocal plot the slope is equal to _____.
Km/Vmax
In the Lineweaver-Burke double reciprocal plot the vertical intercept is equal to ____.
1/Vmax
In the Lineweaver-Burke double reciprocal plot the horizontal intercept is equal to _________.
–1/Km
In competitive inhibition, increasing the concentration of substrate:
Increases the overall rate of the reaction
Which of the following amino acids is capable of acting as a general acid or general base at physiological pH ?
Histidine
Which of the following amino acids can participate in covalent catalysis?
A) Tryptophan
B) Tyrosine
C) Serine
D) Histidine
E) Both C and D are correct
Serine & Histidine
Which of the following is a feature of transition metals that makes them efficient cofactors?
A) Have a high concentration of positive charge
B) Can act as a Lewis acid
C) Have directed valences
D) Can exist as a variety of valence states
E) All of the above are correct
All of the above are correct.
NADPH and NADH are coenzymes found in which class of enzymes?
Dehydrogenases
Which of the following is not present in the active site of alcohol dehydrogenase?
A) Zn++
B) Histidine
C) Cysteine
D) NAD+
E) Proline
Proline















