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BIOCHEMISTRY 411
EXAM 2
Name___________________
I.D.___________
A
CH2CH2CH2CH2CH2COOH
C
CH2CH2COOH
B
CH2CH2CH2CH2COOH
D
CH2CH2CH2COOH
6. If Knoop wanted find benzoate in the urine of his dogs, which compound above would he feed them:
a) A
b) B
c) B or C
d) C
e) C or D
7.
a)
b)
c)
d)
e)
8.
a)
b)
9.
a)
b)
c)
d)
e)
C and D are distinguished from the other two because C or D:
have an odd number of carbon atoms in their chains
are the only ones that would form phenylacetate on -oxidation
are the only ones that would form one acetyl-CoA on -oxidation
are the only ones that would require no FAD to be oxidized
are the only ones that would form propionyl-CoA on -oxidation
Which acyl CoA would yielded 29 ATPs upon complete combustion to CO 2 + H2O?
c) CH CH=CHCOSCoA
e) CH CH CH CH CH COSCoA
3 2 2 2 2
3
d)
CH3CH2CH2CH2COSCoA
CH3CH2CH2COSCoA
CH3COSCoA
In all probability, a photosynthetic organism that lacked photosystem I would:
still be able to synthesize NADPH via the light reaction
still be able to reduce ferredoxin
not be able to survive
still be able to synthesize ATP
a, b and d
10. If you were asked to name metal ions that are in the photosynthesis systems, you would say:
a) Na+, Ca2+, Fe3+, Mg2+
c) NH4+, Na+, K+, Mn2+
e) Mn2+, Mg2+, Fe3+, Cu2+
b) Fe3+, K+, Cu2+, Co2+
d) Ca2+, Mn2+, Zn2+, Fe3+
11.
a)
b)
c)
d)
e)
Which statement is correct regarding Fo and CFo:
both are found in the mitochondria
both are found in chloroplasts associated with the thylakoid membrane or stromal surface
both are hydrophobic transmembrane proteins that contain a proton-translocating channel
both bind ADP and Pi and force the synthesis of ATP
both are components of PSII
12.
a.
b.
c.
d.
e.
Does the cyclic pathway in photosynthesis result in the evolution of O2?
No
Yes
No, but it can if the electrons are returned to the cytochrome b 6 f complex
Yes, but only when there is insufficient NADPH
Yes, but only in a C4 plant
13. Does the cyclic pathway in photosynthesis result in the synthesis of ATP
a. No
b. Yes
c.
d.
e.
No, ATP is sufficient and no more is need to be synthesized
No, the cyclic pathway is required to synthesize NADPH, not ATP
Yes, but only in a C4 plant
14. Shinning a light at 680 nm on a plant is guaranteed to:
a. evolve oxygen
c. activate an electron in PSII
b. oxidize water
d. stimulate ATP synthesis
e. all of the above
15. The ratio of photons/H2O molecules required to reduce one NADP+ to NADPH is:
a. 1:3
b. 4:1
c. 3:1
d. 2:1
e. 1:2
16. The formation of this compound directly involves the NADPH generated in the light reaction:
a. glyceraldehyde-3-PO4
c. ribulose-1,5 bisPO4
e. H2O
b. DHAP
d. fructose-6-PO4
17. The enzyme that catalyzes the reaction in question 20 is:
a. a transketolase
c. a phosphatase
b. a transaldolase
d. an oxidoreductase
18.
a.
b.
c.
d.
e.
e. an isomerase
Chylomicron remnants form when:
fatty acids, mainly as triacylglycerols are digested in the liver
LDL is taken into the tissue
The triacylglycerols of VLDL are released by the action of lipoprotein lipase
IDL reacts with cholesterol esters through the action of LCAT
none of the above
19. Acyl-CoA dehydrogenase is an FAD-requiring enzyme. Which of the following could be a substrate:
CH3CH2CH2CH2COSCoA
H
b) CH CH C=CCOSCoA
3 2
H
a)
CH3CH2CH2CH2COSACP
HH
d) CH3CH2C=CCOSCoA
c)
e)
OH
CH3CH2CCH2COSCoA
H
20. Which fatty acid has propionyl-CoA carboxylase in its metabolic pathway:
a) CH3CH2CH2CH2COSACP
c) CH CH CH CH CH COSCoA
e) CH CH CH CH COSCoA
3
b) CH3CH2CH2CH2CH2COSACP
2
2
2
2
3
2
2
d) CH3CH2CH2COSCoA
Study the compound shown below and answer questions 25-29:
OH
O
-O2C-CH2-C-CH2-C-SCoA
CH3
21. The name of the above compound is:
a. hydoxyacetyl-CoA
c. HMG-CoA
b. acetoacetyl-CoA
d. D--hydroxybutyrate
e. succinyl-CoA
22. The above compound is an intermediate in:
a. ketogenesis
c. fatty acid biosynthesis
b. cholesterol biosynthesis
d. a and b
e. a, b, and c
23.
a.
b.
c.
A lyase enzyme acting on the compound would convert into into:
acetyl-CoA and acetoacetyl-CoA
d. acetoacetyl-CoA and acetate
acetyl-CoA and -hydroxybutyrate
e. mevalonate
acetyl-CoA and acetoacetate
2
28.
a.
b.
c.
An enzyme using two molecules of NADPH would convert this molecule into:
acetyl-CoA and acetoacetyl-CoA
d. acetoacetyl-CoA and acetate
acetyl-CoA and -hydroxybutyrate
e. mevalonate
acetyl-CoA and acetoacetate
29. The formation of this molecule requires the condensation of:
a. two acetyl-CoAs
d. three acetyl-CoA molecules
b. one acetoacetate and one acetyl-CoA
e. acetyl-CoA and mevalonate
c. a succinyl-CoA and an acetyl-CoA
PROBLEM SOLVING, SHORT ANSWER
(2 pts each) Identify the following based on the description:
“You’ll find me in the mitochondria and cytosol. I am not very big, but my function is extensive. I am one of
the big four in a major pathway and I have 4 carbons. I play a prominent role in C4 plants. You may say that I catch
CO2, but that is wrong. Some consider me the great communicator. I even have two enzymes named for me. When
you think of fatty acid synthesis, I should come strongly in mind. Who am I? _L-malate________
“I am an enzyme. Some think I may be the most important enzyme in fatty acid biosynthesis, but I like to
think of my importance in photosynthesis”. Why? Because if it wasn’t for me bundle sheath cells would starve of CO 2
and fatty acids synthesis would lack an essential coenzyme”. Who am I? _Malic enzyme_________
“I am only found in plants. Call me a miracle worker because of me plants conduct a reaction that is
impossible in animal cells. The secret is the way I use ATP. Some call me a kinase, but I like to take it one step further.
You must identify my substrate to get my name”. What is my full name? _Pyruvate phosphate dikinase__
“I am the last compound formed after 3 successive kinase reactions. To identify me, you must think of the
building unit of the cholesterol molecule. It may also help to know that I isomerize rapidly to form another molecule
that has my same basic structure but different position of double bonds. Who am I? _Isopentenyl pyrophosphate____
(5 points) DISCUSSION
Discuss the events that take place when a cell takes up cholesterol from the plasma. Use the terms ACAT,
apoB100, endosome, and LDL in your discussion, but put them in chronological order. Use full sentences, as you
would see in your textbook. There will be NO points for simply defining terms or drawing a diagram with no text.