exam 3 fall 2008 - indiana university...

Chemistry C483 Biological Chemistry

Fall 2008

Exam #3

December 2, 2008

Specific metabolic pathways can be found on page 15 & 16. You may tear

this page free. 4 is blank and may be used as scratch paper.

Name_____________________________________________________

C483 Fall 2008 Exam 3

Exam points

1. _________________/13 pts

2. _________________/ 9 pts

3. _________________/ 8 pts

4. _________________/ 16 pts

5. _________________/ 6 pts

6. _________________/ 9 pts

7. _________________/ 12 pts

8. _________________/ 9 pts

9. _________________/ 3 pts

10._________________/ 15 pts

Extra. ______________/2 pts

Total_______________________/100pts


1. (13 pts) Which of the ten enzymes of glycolysis are being described? For some statements, more

than one enzyme may fit the description: You must include all that apply to receive credit for the

answer. Including incorrect answers will lead to no credit for that description. You may use an

enzyme more than once.

a. Catalyzes a regulated reaction

b. Catalyzes a reaction that requires ATP

c. Catalyzes a reaction that produces ATP

d. Catalyzes a reaction that produces

NADH

e. Inhibition of this enzyme would result in

the NET yield of 1 NADH and a NET loss

of 2 ATP, instead of the normal

glycolytic yield.

f. Catalyzes a lyase reaction

g. Catalyzes a transferase reaction

h. Catalyzes the phosphorylation of its

substrate

a. ___________________________

b. ___________________________

c. ___________________________

d. ___________________________

e. ___________________________

f. ___________________________

g. ___________________________

h. ___________________________


i. Fructose 2,6-bisphosphate is an

allosteric activator of this enzyme

j. These enzymes catalyze reactions with

a ∆G close to, or equal to, zero

k. These enzymes are bypassed in

gluconeogenesis

l. A product of this enzyme is

2-phosphoglycerate

m. Catalyzes an isomerase reaction

i. __________________________

j. ___________________________

k. ___________________________

l. ___________________________

m. ___________________________


2. (9 pts) Indicate if the following statements describe an anabolic pathway (synthesis), a catabolic

pathway (degradation), or both. You may use an answer more than once.

a. Glycolysis

b. Gluconeogenesis

c. Results in a NET loss of energy

d. Overall, the process is reductive

e. Products of this process converge

f. This type of pathway leads to the

production of reduced cofactors (NADH,

FADH2)

g. β-oxidation

h. Glycogen metabolism

i. Pentose phosphate pathway

a. ___________________________

b. ___________________________

c. ___________________________

d. ___________________________

e. ___________________________

f. ___________________________

g. ___________________________

h. ___________________________

i. ___________________________


3. (8 pts) For the following statements, indicate which of the nine coenzymes initially discussed in

class (ATP, NAD+, NADP

+, FMN, FAD, CoA, TPP, THF, or lipoamide) fit the description. For some

statements, more than one coenzyme may fit the description: You must include all that apply to

receive credit for the answer. Including incorrect answers will lead to no credit for that description.

You may use a coenzyme more than once. (If you need complete names of the coenzymes, you can

find them on page 16).

a. Transfers an acyl group

b. Contains an AMP moiety

c. Transfers C1 units

d. Involved in oxidation/reduction

reactions

e. Accepts and donates electrons one at a

time

f. May be involved in the following

reaction:

g. Works with kinases

h. A prosthetic group

a. ___________________________

b. ___________________________

c. ___________________________

d. ___________________________

e. ___________________________

f. ___________________________

g. ___________________________

h. ___________________________

C483 Fall 2008 Exam #1

4. (16 pts) The major source of cellular energy is adenosine triphosphate (ATP).

a. Draw the structure of ATP. Include Mg2+

in your structure in one of the two correct

locations.

b. Circle all the atoms present in the phosphoryl group which is transferred by ATP during a

kinase reaction.

c. Give 2 reasons why the phosphoanhydride bond of ATP is a high energy bond.

d. What is the energy, in kJ/mol, released from hydrolysis of 1 mol ATP to ADP + Pi?


5. (6 pts) A common coenzyme in metabolism is NAD

a. NAD+ accepts a hydride ion. What is a hydride ion?

b. In the molecule below

A common coenzyme in metabolism is NAD+.

accepts a hydride ion. What is a hydride ion?

In the molecule below, circle the atom (or atoms) that accepts the hydride ion.

the hydride ion.


6. (9 pts) Pentose Phosphate Pathway

a. Using the reaction numbers indicted in the

the reactions that will occur if the cell needs to produce

b. Using the reaction numbers indicted in the diagram above indicate, in the correct order,


c. Using the reaction numbers indicted in the diagram above indicat


Pentose Phosphate Pathway

reaction numbers indicted in the diagram above indicate, in

the reactions that will occur if the cell needs to produce only NADPH.

Using the reaction numbers indicted in the diagram above indicate, in the correct order,

the reactions that will occur if the cell needs to produce only ribose-5-


the reactions that will occur if the cell needs to produce only ATP.

indicate, in the correct order,


-phosphate.

e, in the correct order,


7. (12 pts) Indicate if the following will increase, decrease, or remain unaffected if glucose levels

are high.

a. Glycolysis

b. Pyruvate dehydrogenase

c. The citric acid cycle

d. Oxidative phosphorylation

e. Gluconeogenesis

f. Glycogen synthesis

g. Glycogen degradation

h. Triacylglyceride synthesis

i. Triacylglyceride

degradation

j. Insulin levels

k. Glucagon levels

l. Epinephrine levels

a. ___________________________

b. ___________________________

c. ___________________________

d. ___________________________

e. ___________________________

f. ___________________________

g. ___________________________

h. ___________________________

i. ___________________________

j. ___________________________

k. ___________________________

l. ___________________________


8. (9 pts) The fatty acid arachidate (20:0) is degraded by ββββ-oxidation (the ββββ-oxdation pathway is

provided on page 15).

a. How many rounds of β-oxidation will it undergo?

b. How much ATP is generated from the complete oxidation of arachidate? (Show your

work).


9. (3 pts). What is the role of cytochrome c in oxidative phosphorylation?

10. (15 pts). You must answer 5 of the following 6 questions (a-f). Please keep your answers succinct,

but complete. If you answer more than 5, we will only grade the first 5.

a. A mutase is an isomerase enzyme. What is unique about a mutase?

b. Under anaerobic conditions, what two molecules can pyruvate be converted to?

c. What is the purpose of the Cori Cycle?


d. When processed through glycolysis, why is more energy produced from a

monosaccharide released from a linear portion of glycogen instead of one released from

a branching point?

e. What molecule is pyruvate converted to by the enzyme pyruvate dehydrogenase?

f. Why does oxidation of NADH to NAD+ result in 1 more ATP than oxidation of FADH2 to

FAD?

Extra Credit (2 pts). Fill in the blank:

To show why metabolism occurs in discreet steps instead of one combustion reaction, we

watched a video where a ________________ was ignited.


Intentionally left blank


You may find the following information helpful as you take this exam:You may find the following information helpful as you take this exam:


Full names of the coenzymes mentioned in question 3:

Adenosine triphosphate (ATP), Nicotinamide adenine dinucleotide

dinucleotide phosphate (NADPH),

Coenzyme A (CoA), thiamine pyrophosphate

Full names of the coenzymes mentioned in question 3:

Nicotinamide adenine dinucleotide (NAD+), nicotinamide adenine

(NADPH), flavin mononucleoside (FMN), flavin adenine dinucleotide

thiamine pyrophosphate (TPP), Tehtrahydrofolate (THF).

nicotinamide adenine

flavin adenine dinucleotide (FAD),

exam 3 fall 2008 - indiana university...

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