Thursday, August 23, 2012

Glycolysis- Multiple Choice Questions

1). A patient has chronic obstructive pulmonary disease, enough oxygen is not reaching her tissues.  All of the followings are  expected except-
a) The electron transport chain would be inhibited
b) Glycolysis would be activated by a low ATP/ADP ratio
c) More than normal amounts of ATP would be synthesized .
d) Concentrations of NADH and pyruvate would be lower than normal
e) More than normal amounts of lactate would be produced
2). A 45- year- old woman is diagnosed with breast cancer. The oncologist orders a positron emission tomography(PET) scan of the head to rule out metastasis. This imaging modality covalently links a radioactive isotope most commonly to Glucose to appreciate highly active areas in the body such as tumor. Which of the following traps the tracer in the cell ?
a) Insulin
b) GLUT-1
c) GLUT-4
d) Glucokinase
e) PFK-1
3) A 45-year-old obese man complains of having to get up frequently to urinate at night-time. He has also noticed that he is constantly thirsty and hungry. The patient is diagnosed with type 2 diabetes mellitus. If this is a problem at the level of glucose transporters , which tissue would be most affected?
a) Liver
b) Red blood cells
c) Muscle and adipose tissue
d) Brain tissue
e) Small intestine.
4) A 24-year woman is getting training for her first marathon. Her coach instructed her to keep a pace that allows her to stay below her anaerobic threshold. Under such conditions pyruvate does not accumulate as it is converted to-
a) Ethanol
b) Lactic acid
c) Acetyl co A
d) Alanine
e) Oxaloacetate.
5) A patient presents with dizziness, fatigue and tremors. A fingerstick test indicates a blood glucose level of 45 mg/dl (hypoglycemia). Glucagon is released under such condition . Which of the following allosteric modifier of PFK-1 would be  most effective in switching off glycolysis ?
a) Low level of citrate
b) Low level of Fr, 2,6 bisphosphate
c) Low level of ATP
d) Low level of NAD+
e) Low level of Glucose-6-P
6) A 30 -year-old woman is enduring her second trimester of pregnancy. The  greater affinity fetal hemoglobin acquires oxygen released from the lesser affinity maternal hemoglobin due to the effect of an allosteric modifier, which is-
a) Fr-2,6 bisphosphate
b) 2,3 bisphosphoglycerate
c) Citrate
d) Acetyl co A
e) Fr-1,6 bisphosphoglycerate
7) A pediatric hematologist sees an 18 month-old patient with jaundice, splenomegaly and hemolytic anemia. Blood smear indicates red blood cells that are more rigid in appearance than normal. A diagnosis of pyruvate kinase deficiency is made. What products would be made in low amounts ?
a) Acetyl co A
b) Glucose
c) Lactate
d) ATP
e) Alanine
8)  In an embryo with a complete deficiency of pyruvate kinase, how many net moles of ATP would be generated in the conversion of one mole of glucose to one mole of pyruvate ?
a) 0
b) 1
c) 2
d) 3
e) 4
9) Which out of the following enzymes cleaves a carbon-carbon bond in the pathway of glycolysis ?
a) Aldolase
b) Glyceraldehyde-3-P dehydrogenase
c) Enolase
d) Phosphoglycerate kinase
e) Phosphoglycerate mutase
10) After a heavy meal, which out of the following allosteric activator would be most effective in increasing the rate of glycolysis ?
a) ATP
b) Citrate
c) Acetyl co A
d) Fr-2,6 bisphosphate
e) 2,3 bisphosphoglycerate.
11) Compared with the resting state a vigorously contracting muscle shows-
a) An increased conversion of pyruvate to lactate
b) Increased oxidation of pyruvate to CO2
c) A decreased concentration of AMP
d) Decreased level of fr-2,6 bisphosphate
e) Decreased ratio of NADH/NAD+
12) A 24 -year-old man presented with symptoms of shortness of breath, weakness and fatigue. His Hemoglobin level was 7G/dl. Red blood cell isolated from the patient showed abnormally low-level of lactate. A deficiency of which of the following enzymes would be the most likely cause for patient’s anemia?
a) Phosphoglucose isomerase
b) Phosphofructokinase
c) Hexokinase
d) Glucokinase
e) Pyruvate kinase.
13) A mixture of sodium fluoride and potassium oxalate is added to sample collected for blood glucose estimation to prevent loss of glucose by anaerobic glycolysis. Fluoride is an inhibitor of glycolysis. Which of the following enzymes is inhibited by fluoride ?
a) Hexokinase
b) Phosphofructokinase
c) Glyceraldehyde-3-P dehydrogenase
d) Lactate dehydrogenase
e) Enolase
14) Oxamate is a competitive inhibitor of which of the following enzymes ?
a) Hexokinase
b) Phosphofructokinase
c) Glyceraldehyde-3-P dehydrogenase
d) Lactate dehydrogenase
e) Pyruvate dehydrogenase
15)  Which out of the following enzymes of glycolysis is inhibited by Arsenate ?
 a) Hexokinase
b) Phosphofructokinase
c) Glyceraldehyde-3-P dehydrogenase
d) Lactate dehydrogenase
e) Pyruvate dehydrogenase
1)-e                2)-b                3)-c                 4)-c                 5)-b                6)-b               

7)-d                8)-a                9)-a                10)-d              11)-a              12)-e

13)-e              14)-d              15)-c

Best Wishes: Dr.Ehab Aboueladab, Tel:01007834123, ehab fathy aboueladab
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