Biol 638, Exam-3 (Code-1)
Biology 638 – Biochemistry II
Exam-3
(Note that you are not allowed to use any calculator)
1. In the non-cyclic pathway, electron pathway is ____. Select the most accurate one.
a. PSII → PC → Cyt b6f → PC → PSI → Fd-NADP+ reductase → Fd → NADPH
b. PSII → PQ → Cyt b6f → PC → PSI → Fd → Fd-NADP+ reductase → NADPH
c. PSII → PC → Cyt b6f → PQ → PSI → Fd-NADP+ reductase → Fd → NADPH
d. PSII → PQ →Cyt b6f → PQ → PSI → Fd → Fd-NADP+ reductase → NADPH
e. None of the above
The following sequence of reactions represents the β-oxidation pathway for fatty acids in
mitochondria.
Fatty acid
E0
Acetyl-CoA
F1
E4
E1
F4
F2
E2
E3
F3
F1, F2, F3, and F4 are substrates. E0, E1, E2, E3, and E4 are enzymes. The following two
questions refer to this pathway.
2.
F4 is _____.
a.
β-ketoacyl-CoA
c.
β-hydroxyacyl-CoA
e.
None of the above
b. trans-Δ2-enoyl-CoA
d. fatty acyl-CoA
3.
E3 is a(n) _____.
a.
hydratase
c. isomerase
e. None of them
b. hydrolase
d. thiolase
Biol 638, Exam-3 (Code-1)
4. How many acetyl-CoA and ATP molecules are required to make ten glucose molecules
through the glyoxylate pathway and gluconeogenesis? Assume that NADH, FADH2, and
GTP are equivalent to three, two and one ATP, respectively.
a. 40 Acetyl-CoA and 40ATP
b. 20 Acetyl-CoA and 40 ATP
c. 40 Acetyl-CoA and 20 ATP
d. 20 Acetyl-CoA and 20 ATP
e. None of them
5. How many moles of ATP are produced from the complete oxidation of (cis Δ9,12,15 C21) fatty
acid to CO2?
a. 164
b. 166
c. 168
d. 170
e. None of them
6. Select the correct pathway of Cori cycle.
a. In muscle (glucose → lactate → pyruvate) via blood to liver
glucose) via blood to muscle (glucose → so on).
b. In liver (glucose → pyruvate → lactate) via blood to muscle
glucose) via blood to liver (glucose → so on).
c. In liver (glucose → lactate → pyruvate) via blood to muscle
glucose) via blood to liver (glucose → so on).
d. In muscle (glucose → pyruvate → lactate) via blood to liver
glucose) via blood to muscle (glucose → so on).
e. None of the above
(pyruvate → lactate →
(lactate → pyruvate →
(pyruvate → lactate →
(lactate → pyruvate →
Biol 638, Exam-3 (Code-1)
7. Assume that you are a CSI agent and examine a liver specimen from a fresh body. You find
that the [NADP+]/[NADPH] ratio is 0.1, and the liver specimen smell sweet. Your
suggestion of cause of death is: _______.
a. natural death by poor nutrition
b. CN- poisoning
c. suffocation
d. large dose of epinephrine injection
e. large dose of KCl injection (Very high K+ ion in blood stops heart beat)
8. When O2 instead of CO2 enters in Calvin cycle, ______ is produced instead of GAP.
b. 3PG
c. 2PG
d. R5P
e. None of them
a. CO2
9. The overall β-oxidation of C16 fatty acid is:
C16-fatty acid + [X]FAD + [Y]NAD+ + [Z]CoA + [W]ATP →
[a]acetyl-CoA + [b]FADH2 + [c]NADH + [W](ADP + Pi)
W is ____.
a. 2
b. 4
c. 8
d. 10
e. None of them
10. How many ATP molecules are produced from complete oxidation of two glucose molecule
in the pentose phosphate pathway? Assume that one NADPH is equivalent to 3 ATPs.
a. 66
b. 68
c. 70
d. 72
e. Non of them
11. Assume that a CAM plant produces ten G6P using a best combination of the cyclic and noncyclic pathways (i.e., you cannot assume that NADPH is equivalent to three ATP). How
many photons are necessary for this synthesis? Select the closet one.
a. 500
b. 550
c. 600
d. 650
e. 700
Biol 638, Exam-3 (Code-1)
For question 12 – 25, select that statement that contains the most significant mistake(s). If
none of (a, b, c, d) does not contain significant mistake(s) (i.e. all statements are correct), then
select “e. None of the above.”
12. The followings are some descriptions of pyruvate carboxylase.
a. Pyruvate carboxylase has a covalently connected biotin in the active site.
b. Pyruvate carboxylase is inhibited by alanine.
c. Acetyl-CoA is a powerful allosteric activator of pyruvate carboxylase.
d. In the pyruvate carboxylase reaction, HCO3- is phosphorylated by ATP and the
phosphorylated HCO3- reacts with the bound cofactor.
e. None of the above
13. The followings are some descriptions of carbohydrate metabolism.
a. If isocitrate lyase and malate synthase are present in mitochondrion of animal liver cells,
animal can synthesize glucose from either amino acids or fatty acids.
b. If liver PFK-2/FBPase-2 is replaced with the heart muscle isozyme, glucogeogenesis
would not be occurred.
c. If gluconeogenesis is started at pyruvate, the next compound is oxaloacetate.
d. Fuctose-1,6-bisphosphatase and Glucose-6-phosphatase are only present in liver cells.
e. None of the above.
14. The followings are some descriptions of carbohydrate metabolism.
a. Oligosaccharides are constructed on dolichol in the lumen of rough ER.
b. The oligosaccharides on Asn are attached during the protein synthesis.
c. In a posttranslational modification in Golgi apparatus, oligosaccharides are constructed
on Ser or Thr residues of proteins.
d. There are three distinct linkages between protein and origosaccharides.
e. None of the above
15. The followings are some descriptions of carbohydrate metabolism.
a. Transketolase has a TPP coenzyme and carries a C2-unit.
b. Transaldolase has a neutral Lys and carries a C3-unit.
c. Pentose phosphate pathway is controlled by the rate of the 6-phosphogluconate
dehydrogenease reaction.
d. Ru5P to R5P conversion in pentose phosphate pathway is catalyzed by an isomerase.
e. None of the above.
16. The followings are some descriptions of photosynthesis.
a. Light reaction and dark reaction of plant photosynthesis occur in thylakoid and stroma,
respectively.
b. Chlorophylls cannot absorb most light between 480 nm and 620 nm wavelengths.
c. Chlorophyll contains Mg2+ ion.
d. Photosynthesis is carried out at chloroplasts in plant cells.
e. None of the above
Biol 638, Exam-3 (Code-1)
17. The followings are some descriptions of photosynthesis.
a. One of the most important enzymes of Calvin cycle is Rubisco.
b. Rubisco is a carboxylase, but does not contain cofactor biotin.
c. FBPase and SBPase are activated by Fd-NADP+ reductase.
d. Dark reaction in photosynthesis is called Calvin cycle.
e. None of the above
18. The followings are some descriptions of photosynthesis and gluconeogenesis.
a. Pyruvate to PEP conversion is carried out by two enzymes in gluconeogenesis.
b. Pyruvate to PEP conversion is carried out by one enzyme in C4 plants.
c. Pyruvate to oxaloacetate conversion is carried out by one enzyme in gluconeogenesis.
d. Pyruvate to oxaloacetate conversion is carried out two enzymes in C4 plants.
e. None of the above.
19. The followings are some descriptions of lipid metabolism.
a. Role of Ca2+ in the active site of phospholipase A2 is to polarize the bound water that
attacks on carbonyl carbon of fatty acid.
b. The acyl group of acyl-CoA in cytosol is carried by carnitine into the mitochondrial
matrix.
c. Formation of acyl-CoA requires two ATP hydrolyses (i.e., ATP + H2O → ADP + Pi is
one ATP hydrolysis).
d. Vitamin B12 is required to convert methylmalonyl-CoA to succinyl-CoA.
e. None of the above.
20. The followings are some descriptions of lipid metabolism.
a. Attaching CoA to fatty acid weakens the Cα-Cβ bond of fatty acid.
b. Very long chain fatty acids are shortened by peroxisomal β-oxidation.
c. Triacylglycerol lipase is regulated by substrate availability.
d. HMG-CoA lyase is a mitochondrion enzyme
e. None of the above.
21. The followings are some descriptions of gluconeogenesis.
a. Gluconeogenesis only occurs when the blood glucose level is low.
b. Oxaloacetate in mitochondrion is transported by malate-aspartate shuttle whereas PEP is
transported through the specific transport protein.
c. In gluconeogenesis, the phosphate groups of FBP and G6P are removed by hydrolysis.
d. High citrate level in liver inhibits gluconeogenesis.
e. None of the above
22. The followings are some descriptions of pentose phosphate pathway.
a. Many biological redox reactions cannot use both NADH and NADPH.
b. NADPH and R5P are the major products of pentose phosphate pathway.
c. About 3 % of glucose in liver is oxidized to produce NADPH.
d. In many cases, GSH but not NADPH is used to reduce directly H2O2 and R-O-O-H
produced in cell.
e. None of the above
Biol 638, Exam-3 (Code-1)
23. The followings are some descriptions of photosynthesis.
a. OEC contains a Mn4 cluster.
b. When electron flows in the non-cyclic pathway in chloroplasts, ATP and NADPH are
produced.
c. PQH2 stimulates phosphorylation of LHC.
d. When electron passes through Cyt b6f, proton is pumped from thylakoid to stroma.
e. None of the above.
24. The followings are some descriptions of rubisco.
a. Rubisco activity is regulated by H+ concentration in stroma.
b. Rubisco activity is regulated by Mg2+ concentration in stroma.
c. Rubisco activity is regulated by CA1P concentration in stroma.
d. Rubisco activity is regulated by Cl- concentration in stroma.
e. None of the above
25. The followings are some descriptions of lipid metabolism.
a. Ketone bodies are composed of acetoacetate and hydroxybutyrate, which are the major
energy source during starvation.
b. One acetoacetate molecule is synthesized from three acetyl-CoA molecules.
c. When ketone bodies are major energy source, people smell sweet.
d. Ketone bodies are produced when the oxaloacetate concentration in liver is very low.
e. None of the above.