2. List sequentially the enzymes involved in the tricarboxylic acid
cycle, beginning with pyruvate as the substrate. (10 points)
pyruvate dehydrogenase
citrate synthase
aconitase
isocitrate dehydrogenase
a-ketoglutarate
dehydrogenase
succinate thiokinase
succinate dehydrogenase
fumarase
malate dehydrogenase
3. Schematically diagram the electron transport chain, indicating the
major molecules, enzymes of each site and where ATP are produced. (10 points)
4. "Metabolism" is a general term. List the activities which comprise
this term. (5 points)
Anabolism and catabolism
1. Catabolism of dietary macromolecules into
building block molecules
2. Anabolism of building block molecules into
macromolecules
3. Synthesis of building block molecules
4. Synthesis and degradation of specialized
molecules
5. Using a tabular format, compare and contrast fatty acid anabolism
and catabolism with respect to products and reactants, cofactors, location,
differing intermediates and how reactions are carried out. (10 points)
Anabolism
Catabolism
reactants -> products acetyl CoA -> palmitic acid
fatty acyl CoA -> acetyl CoA
cofactors
NADPH
FAD and NAD+
location
cytoplasm
matrix
differing intermediates
D
L
how reactions are carried out 1 polypeptide with
multiple enzymes
multiple enzyme
activities
6. What is the net energy yield (ATP equivalents) from a triglyceride
molecule composed of one palmitic, one stearic and one oleic acid molecule.
Ignore the energy contribution from glycerol. (10 points)
palmitic - 7 cycles
stearic - 8 cycles oleic
- "8" cycles
-2 activate
-2
-2
7x17 ATP per cycle
8x17
8x17
12 ATP from other acetyl CoA
12
12
-2 for double bond
_________________
______
______
129
146
144
total 421 ATP net
7. Demonstrate the conversion of palmitic acid to stearic acid by outlining
the molecules involved, and enzymes and coenzymes involved in their interconversion.
(10 points)
Part B. Multiple Choice (3 points each). Circle the letter of the most
correct answer.
1. Hexokinase
a. is not regulated
b. is regulated by NADH
c. is regulated by glucose-6-phosphate
d. is regulated by ATP
correct answer is C
2. An amphibolic pathway
a. is involved in anabolism
b. is involved in both anabolism and catabolism
c. is involved in catabolism
d. is involved in neither anabolism or catabolism
correct answer is B
3. The energy yield of glycolysis aerobically
a. is 8 ATP
b. is 6 ATP
c. is 2 ATP
d. is 2 ATP more than anaerobically
no correct answer - depends on transporter used
4. The chemiosmotic coupling hypothesis
a. says that two protons cause the synthesis of
an ATP
b. says that mitochondria must be intact.
c. has a great deal of experimental evidence to
back it up
d. a and b
e. b and c
f. all of the above
correct answer is F
5. ß-oxidation
a. requires carnitine
b. requires NADP+
c. requires FAD
d. requires ATP
e. a and c
f. all but b
g. all but d
correct answer is F
6. Phosphofructokinase
a. is the rate limiting step of glycolysis
b. is inhibited by ATP
c. is activated by NAD+
d. all of the above
best answer is D, but we did not discuss all these molecules
7. The rate limiting step of the Krebs cycle is
a. a-ketoglutarate
dehydrogenase
b. succinate thiokinase
c. citrate synthase
d. fumarase
correct answer is C
8. The Krebs cycle
a. occurs in the cytoplasm
b. occurs in the mitochondria
c. occurs in endoplasmic
reticulum
d. all of the above
correct answer is B
9. One of the products of ß-oxidation
of odd-chain-length fatty acids is
a. FADH2
b. succinyl CoA
c. propionyl CoA
d. a and b
e. b and c
f. a and c
correct answer is C
10. Fatty acid elongation occurs
a. in mitochondria
b. in the endoplasmic
reticulum
c. in the cytoplasm
d. in the intermembrane
space of mitochondria
correct answer is B