BIOCHEMISTRY: TCA CYCLE, GLUCONEOGENESIS, ENZYME KINETICS
DIRECTIONS : PLEASE CAREFULLY READ ALL QUESTIONS AND ANSWER ALL QUESTIONS.
OUTLINES ARE ATTACHED TO THIS POST AS A REFERENCE
DUE TODAY: @ 6:00PM EASTERN STANDARD TIME
1.) The equilibrium constant of an uncatalyzed reaction Keq is 0.5. If an enzyme having a Km of 0.01M and Vmax of 0.1 umoles/min is used to catalyze this same reaction, the Keq of the catalyzed reaction would be:
A. 5
B. 0.005
C. 0.5
D. 0.05
2.) Addition of a competitive inhibitor to an enzymatically catalyzed reaction will
A. increase the affinity the enzyme has for its substrate
B. reduce the Vmax of the reaction
C. increase the substrate concentration required to attain ½ Vmax
3.) The equation below describes the behavior of which of the following reactions obeying Michaelis-Menton kinetics?
Vo = Vmax [S] / (Km + a’ [S])
A. An uninhibited reaction
B. A non competitively inhibited reaction
C. None of the above answers are correct
D. competitively inhibited reaction
4.) Which of the following enzymes covalently modifies the FBP-2/PFK-2 enzyme complex?
A. PFK-2
B. protein kinase A
C. pyruvate kinase
D. PFK-1
5.) For each time (cycle) of the TCA cycle , how many molecules of ATP equivalents are produced ?
A. 24
B. 18
C. 6
D. 12
6.) The first reaction of the tricarboxylic acid cycle condenses the acetyl group, acetyl CoA with which of the following TCA cycle intermediates ?
A. pyruvate
B. oxaloacetate
C. citrate
D. malate
7.) In the TCA cycle TP is produced from CDP and Pi by which of the following mechanisms?
A. substrate level phosphorylation
B. cAMP- dependent kinase phosphorylation
C. reverse phosphorylation
8.) Succinate thiokinase (AKA succinyl – CoA synthetase) cleaves a high energy bond CoA this high energy bond is of which of the following types ?
A. Ester
B carboxylic acid
C.aldehyde
D. thioester
9.) The primary substrate in gluconeogenesis is which of the following ?
A. glicerol
B. fatty acids
C. amino acids
D. glucose
10.)Which of the following results in a futile cycle ?
A. glycolysis is inactive and glycogenesis is active
B. both glycolysis and gluconeogenesis are inactive
C. both glycolysis and gluconeogenesis are active
D. glycolysis is active and gluconeogenesis is inactive
11.) True/ False: Oxaloacetate is permeable to inner mitochondrial membrane
A.True
B.False
12.)The Cori Cycle is best described as which of the following?
A. glucose converted to pyruvate and back to glucose
B. glucose converted to glycogen and back to glucose
C. glucose converted to ATP and back to glucose
D. glucose converted to lactate and back to glucose
13.) True /False the reaction : Acetyl – CoA+ oxaloacetate -> citrate is an anaplerotic reaction
A.True
B.False
14.) When initial reaction velocity is plotted as a function of substrate concentration the kinetics data of non allosterically regulated enzymes generate a curve with
A. linear morphology
B. Hyperbolic morphology
C. zero order morphology
D. sigmoidal morphology
15.) Addition of a competitive inhibitor to an enzymatically catalyzed reaction will
A. increase the affinity the enzyme has for its substrate
B. reduce the Vmax of the reaction
C. increase the substrate concentration required to attain ½ Vmax
