remediation

BMB 514 -- Exam II -- October 6, 2003

Tear off and keep this for your record of your answers.

ANSWER GRID

Version of the Exam: 1A

BMB 514 -- Exam II -- October 6, 2003 Name ___________________________

BEFORE you begin the exam, please complete the following information on your response sheet:

(a) your name and signature (b) your student number (PID)
(c) your college -- in the area under SECTION: mark 001 for CHM student
mark 002 for COM student
(d) your version of the exam is 1A - mark this in the area under FORM

• There are 30 questions on this exam. For each question, mark the letter corresponding to what you consider is the BEST answer on the response sheet provided.
• When you leave the exam room, please turn in your RESPONSE SHEET and your EXAM to the proctors standing by the doors INSIDE the auditorium. Once you exit the auditorium, please DO NOT return until we have reopened the doors (~8:45 a.m.).

• There will be answer keys to this exam outside A-133 Life Sciences after the exam is completed. You may wish to copy your responses from the response sheet onto the answer grid on the first page of this exam so that you can check your results. You can tear off the first page and take it with you.

• You have 60 minutes to complete this exam. We will close the exam promptly at 8:30 a.m. Once we withdraw the boxes for the response sheets from the doors, no additional response sheets will be accepted.

• Do well and good luck.

1. One of your first patients has had a previous heart condition and is currently taking digoxin, a Na+/K+ ATPase inhibitor. One possible side-effect of this type of medication is a decreased ability to absorb which of the following sugars?

A. Glucose and Ribose
B. Fructose and Galactose
C. Galactose and Glucose
D. Glucose and Xyulose
E. Fructose and Ribose

2. A patient suffers from a genetic defect that causes her fructose-2,6,-bisPhosphatase enzyme to remain activated in a well fed state. Which of the following ENZYMEs would be aberrantly ACTIVATED in this patient?

A. Phosphofructokinase (PFK1)
B. Glyceraldehyde 3-P dehydrogenase
C. Phosphoglucose isomerase
D. Fructose 1,6-bisPhosphatase (FBP1)
E. Pyruvate Kinase

3. A person has consumed a large bag of candy corn and his blood glucose is very high. Which of the following best describes the activity of hexokinase and glucokinase in the liver?

	Hexokinase	Glucokinase
A. B. C. D.	At Vmax Below Vmax At Vmax Below Vmax	At Vmax Below Vmax Below Vmax At Vmax

4. A person suffering from a genetic defect that drastically decreases the activity of fructose 1-phosphate aldolase (fructose-1-P aldolase) is at risk of liver damage following a diet high in fructose. What is the best explanation for this complication?

A. A build up of glyceraldehyde
B. ATP depletion due to fructose 1-P build up (i.e. Pi sequestration)
C. high, unregulated fructokinase activity
D. B and C
E. All of the above

5. A patient who happens to be a body builder comes into your office to ask questions concerning her new diet regime that consists of a daily intake of 25-30 raw eggs. You realize that this patient is at risk of a biotin deficiency. What gluconeogenic enzyme would be affected by the loss of this cofactor?

A. phosphoenol pyruvate carboxykinase
B. pyruvate carboxylase
C. glucose-6-phosphatase
D. fructose 1,6-bisphosphatase
E. pyruvate kinase

6. Following the consumption of a high carbohydrate meal, which of the following groups of enzymes would you expect to be NEGATIVELY regulated?

A. phosphoenolpyruvate carboxykinase, glucose 6-phosphatase, fructose 1,6-bisphosphatase
B. fructose 1,6-bisphosphatase, phosphofructokinase, hexokinase
C. phosphoenolpyruvate carboxykinase, pyruvate kinase, pyruvate carboxylase
D. glucose 6-phosphatase, glyceraldehyde 3-P dehydrogenase, glucokinase
E. phosphofructokinase, phosphoenolpyruvate carboxykinase, pyruvate kinase

7. Which of the following is NOT true about the structure of the mitochondria?

A. Contains cristae that are invaginations of the inner membrane.
B. The inner membrane is freely permeable to most small ions.
C. The electron transport chain enzymes are located in the inner membrane.
D. The inner membrane contains a series of specialized transporters.
E. The matrix contains the enzymes required for the TCA cycle and fatty acid oxidation.

8. Following the release of Acetyl CoA from the pyruvate dehydrogenase complex, what two cofactors are necessary for the regeneration of lipoic acid?

A. thiamine pyrophosphate and NAD
B. NAD and biotin
C. Biotin and FAD
D. FAD and NAD
E. thiamine pyrophosphate and FAD

9. The pyruvate dehydrogenase (PDH) complex is tightly regulated by hormones and cellular metabolites. Which of the following are responsible for ACTIVATING the kinase involved in lowering the activity of the PDH complex?

A. Acetyl CoA and Insulin
B. ADP and glucagon
C. Acetyl CoA and pyruvate
D. NADH and Insulin
E. Acetyl CoA and NADH

10. Which of the following correctly describes the TCA cycle?

A. Makes twice as much NADH from one mole glucose than from one mole of alanine
B. Produces one molecule of ATP per cycle
C. Is activated by high levels of NADH and FADH₂ within the cell
D. A and B
E. All of the above

11. A patient with a defective malate dehydrogenase enzyme has unnaturally high intracellular levels of oxaloacetate. The increase level of oxaloacetate would most directly lead to the increased activity of which TCA cycle enzyme?

A. fumarase
B. succinate thiokinase
C. succinate dehydrogenase
D. aconitase
E. citrate synthase

A. + 46 kcal/mole
B. -23 kcal/mole
C. +23 kcal/mol
D. -46 kcal/mole
E. -11.5 kcal/mol

13. A farmer is brought into the emergency room after an incident near a manure pit where he collapsed. He displays no indication of heart problems and you deduce he has been exposed to hydrogen sulfide. If you could isolate his mitochondria and test them for oxidation state of the cofactors and the ability to consume oxygen, which of the following would best describe the profile of cofactors and the effect of an additional treatment of 2,4-DNP to the isolated poisoned mitochondria?

	Cofactors		Effect of 2,4-DNP co-treatment
A. B. C. D. E.	reduced cytochrome c oxidized cytochrome c reduced cytochrome c oxidized Coenzyme Q₁₀ reduced Coenzyme Q₁₀		oxygen consumption restored oxygen consumption is inhibited oxygen consumption is inhibited oxygen consumption is inhibited oxygen consumption is restored

14. Complex V (aka ATP synthase) is the enzyme that produces 95% of your ATP. Which of the following is NOT true about complex V?

A. It requires a membrane potential across the inner membrane of the mitochondria to function.
B. It uses NAD as an essential cofactor.
C. Oligomycin inhibits its function by blocking flow of protons through the complex.
D. ATP production is dependent upon the presence of ADP.
E. It can generate more ATP per mole of NADH then it can per mole of FADH₂, when oxidized by the electron transport chain.

15. Coenzyme Q is correctly described by all of the following EXCEPT?

A. can carry protons and electrons
B. can be reduced by Complex I and Complex II
C. reduced CoQ₁₀ (aka ubiquinol) transfers its electron to Complex III
D. Accepts reducing equivalents from cytochrome a
E. Is lipid soluble

16. A very rapidly growing tumor requires much more ribose -5-P than NADPH from the pentose phosphate pathway. What two enzymes are required to produce ribose-5-P from glycolytic intermediates without producing any NADPH?

A. lactonase and glucose-6-P dehydrogenase
B. glucose -6-P dehydrogenase and ribulose-5-P isomerase
C. transaldolase and transketolase
D. transketolase and ribulose-5-P isomerase
E. lactonase and transaldolase

17. Which of the following is NOT true of Glucose -6-P dehydrogenase?

A. Is the first committed step in the pentose phosphate pathway.
B. Deficiencies can lead to hemolytic anemia under conditions of oxidative stress.
C. Is regulated by ATP.
D. Catalyzes the production of 6-phosphogluconolactone from glucose-6-P.
E. Is essentially irreversible.

18. Which of the following best describes glycogen synthase?

A. Can use a single glucose molecule as a starting point
B. Is responsible for the creation of 1,4 and 1,6 glycosidic bonds
C. It is active when phosphorylated
D. Requires ATP to recycle the UDP that is produced
E. Glucagon can activate it

19. Glycogen phosphorylase is positively regulated by which group of compounds?

A. epinephrine, ATP and glucose
B. glucagon, glucose-1-P and AMP
C. glucagon, epinephrine and ATP
D. ATP, glucose and glucose-6-P
E. Epinephrine, AMP and glucagon

20. Gluconeogenesis requires all of the following enzymes to get passed the "essentially irreversible" steps of glycolysis EXCEPT?

A. Pyruvate carboxylase
B. Glucose 6-phosphatase
C. Malate dehydrogenase
D. Fructose 1,6-bisphosphatase (FBP1)
E. Phosphoglycerate phosphatase

21. Which of the following describe the a-ketoglutarate dehydrogenase complex?

A. Release one mole of CO₂ per mole of a-ketoglutarate oxidized
B. Negatively regulated by succinyl CoA
C. Produces one reducing equivalent and a building block for heme biosynthesis
D. A and B
E. All of the above

22. Storage of energy as fat (triglyceride) is advantageous compared to storage as sugar (or glycogen) because fat:

A. has more carbon atoms per molecule than glucose.
B. can provide almost 10 times the kcal of energy per pound as glycogen.
C. can be more rapidly mobilized than glycogen.
D. is available in circulation in higher amounts than sugar.

23. Which of the following is an essential fatty acid and an omega-3 fatty acid?

A. linoleic acid (C18:D9,12)
B. arachidonic acid (C20:D5,8,11,14)
C. palmitic acid (C16)
D. linolenic acid (C18:D9,12,15)

24. Fatty acid oxidation (b oxidation)

A. occurs entirely in the cytosol.
B. is stimulated when insulin levels are high.
C. involves a transport step that uses carnitine.
D. uses NADP as the acceptor for reducing equivalents.
E. produces less ATP per carbon than glucose.

25. Ketone bodies are a product of fatty acid oxidation that are made

A. in skeletal muscle.
B. in the cytosol.
C. in liver mitochondria.
D. when oxaloacetate levels are high.
E. All of the above.

26. Fatty acid synthesis and fatty acid oxidation both

A. use NAD⁺ as a cofactor.
B. use a pantethenic acid derivative as a cofactor.
C. involve a sequence of enzyme reactions that are carried out in one large complex.
D. are stimulated when ATP and citrate build up in mitochondria.
E. are inhibited by palmitoyl CoA.

27. The denovo synthesis of phospholipids and triglycerides from glucose and fatty acids share a common reaction pathway until after the production of:

A. dihydroxyacetone phosphate.
B. diacylglycerol phosphate.
C. fatty acyl CoA.
D. CDP diacylglycerol.
E. glycerol-3-phosphate.

28. Cholesterol is an important component of biological membranes that has all the following characteristics EXCEPT

A. made from isoprene units.
B. synthesized in the cytosol of most tissues.
C. synthesized using 18 acetyl CoA per molecule of cholesterol.
D. synthesized in a process that is inhibited by insulin.
E. at high levels in the cell will inhibit cholesterol uptake from the blood.

29. A patient is being treated for high circulating cholesterol with one of the 'statin' drugs (lipitor). Which of the following would most likely occur in the liver:

A. HMG-CoA levels would increase.
B. mevalonate levels would increase.
C. isoprene units would build up.
D. ketone body levels would increase.
E. cholesterol levels would increase.

30. An aging professor would like to protect herself against the ravages of reactive oxygen species. Which of the following vitamins would you recommend:

A. A
B. D
C. K
D. E
E. B₁₂

BMB 514
Exam II
October 6, 2003

ANSWER KEY

Version of the Exam: 1A

1.	C	6.	A	11.	E	16.	C	21.	E	26.	B
2.	D	7.	B	12.	D	17.	C	22.	B	27.	B
3.	C	8.	D	13.	C	18.	D	23.	D	28.	D
4.	D	9.	E	14.	B	19.	E	24.	C	29.	A
5.	B	10.	A	15.	D	20.	E	25.	C	30.	D