Carbohydrates Biochemistry Set 5

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Biochemistry (Carbohydrates And Carbohydrate Metabolism Set 5)

MCQ

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1. The synthesis of glucose from pyruvate
by gluconeogenesis

A) Occurs exclusively in the cytosol

B) Requires oxidation/reduction of FAD

C) Requires the participation of biotin

D) Is inhibited by elevated level of insulin

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2. Compared to the resting state, vigorously
contracting muscle shows

A) Decreased concentration of AMP

B) A decreased NADH/NAD+ ratio

C) An increased conversion of pyruvate to lactate

D) Decreased oxidation of pyruvate of CO2 and water

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3. Which one of the following statements
concerning glucose metabolism is correct

A) Pyruvate kinase catalyses an irreversible reaction

B) Glucose enters most cells by a mechanism in which Na+ and glucose are co-transported

C) An elevated level of insulin leads to a decreased level of fructose 2, 6-bisphosphate in hepatocyte

D) The conversion of Glucose to lactate occurs only in the R.B.C

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4. Which of the following enzyme is not
involved in HMP shunt

A) Transketolase

B) Glucose-6-p-dehydrogenase

C) Phosphogluconate dehydrogenase

D) Glyceraldehyde-3-p dehydrogenase

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5. The free energy change, AG

A) Is equal to zero at equilibrium

B) Is equal to –RT in keq

C) Can only be calculated when the reactants and products are present at 1mol/1 concentrations

D) Is directly proportional to the standard free energy change, AG

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6. All of the following statements about the
enzymic complex that carries out the
synthesis of ATP during oxidative
phosphorylation are correct except

A) It is inhibited by oligomycin

B) ) It can bind molecular O2

C) It is located on the matrix side of the inner mitochondrial membrane

D) It can exhibit ATPase activity

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7. For conversion of oxaloacetate to
phosphoenol pyruvate, high energy
molecule is required in the form of

A) GTP (or) ITP

B) None of these

C) GTP only

D) ITP only

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8. Out of 24 mols of ATP formed in TCA cycle,
2 molecules of ATP can be formed at
“substrate level” by which of the
following reaction

A) socitrate→ Oxaloacetate

B) Citric acid→ Isocitric acid

C) Succinic acid→ Fumarate

D) Succinylcat→ Succinic acid

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9. The reaction catalysed by phosphofructokinase

A) Is activated by high concentrations of ATP and citrate

B) Is the rate-limiting reaction of the glycolytic pathway

C) Uses fruitose-1-phosphate as substrate

D) Is inhibited by fructose 2, 6-bisphosphate

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10. Electron transport and phosphorylation
can be uncoupled by compounds that
increase the permeability of the inner
mitochondrial membrane to

A) Protons

B) All of these

C) Electrons

D) Uncouplers

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11. Under standard conditions

A) The standard free energy change ∆G, is equal to 0

B) The free energy change, ∆G°, is equal to the standard free energy change, ∆G°

C) Keq is equal to 1

D) The free energy change ∆G°, is equal to 0

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12. An uncoupler of oxidative phosphorylation such as dinitropheno

A) Inhibits electron transport and ATP synthesis

B) Inhibits electron transport without impairment of ATP synthesis

C) Specially inhibits cytochrome b

D) Allow electron transport to proceed without ATP synthesis

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13. Cori cycle is

A) uptake of glycose

B) reuse of glucose

C) Both (A) & (B

D) Synthesis of glucose

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14. Which one of the following compounds
cannot give rise to the net synthesis of
Glucose

A) Lactate

B) α-ketoglutarate

C) Acetyl CoA

D) Glycerol

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15. How many ATPs are produced in the
conversion of phosphoenol pyruvate to
citrate

A) 4

B) 2

C) 6

D) 1

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16. Phenylalanine is the precursor of

A) Throxine

B) Histamine

C) Tyrosine

D) L-DOPA

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17. Reduced glutathione functions in R.B.Cs
to

A) Reduce oxidizing agents such as H2O2

B) Produce NADPH

C) Produce NADH

D) Reduce methemoglobin to hemoglobin

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18. Phenylalanine is the precursor of

A) L-DOPA

B) Tyrosine

C) Histamine

D) Throxine

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19. Glycogen is present in all body tissues
except

A) Brain

B) Kidney

C) Stomach

D) Liver

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20. The reaction catalysed by phosphofructokinase

A) Uses fruitose-1-phosphate as substrate

B) Is inhibited by fructose 2, 6-bisphosphate

C) Is activated by high concentrations of ATP and citrate

D) Is the rate-limiting reaction of the glycolytic pathway

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21. In presence of the following cofactor,
pyruvate carboxylase converts pyruvate
to oxaloacetate

A) CO2

B) Protein

C) ATP, Protein and CO2

D) CO2 and ATP

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22. Which one of the following would be
expected in pyruvate kinase deficiency

A) Increased phosphorylation of Glucose to Glucose-6-phosphate

B) Hemolytic anemia

C) Decreased ratio of ADP to ATP in R.B.C

D) Increased levels of lactate in the R.B.C

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23. An allosteric enzyme responsible for
controlling the rate of T.C.A cycle is

A) Malate dehydrogenase

B) Aconitase

C) Fumarase

D) Isocitrate dehydrogenase

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24. Which of the following statements
regarding T.C.A cycle is true

A) It occurs in cytosol

B) It contains no intermediates for GluconeogenesisIt contains no intermediates for Gluconeogenesis

C) It is amphibolic in nature

D) It is an anaerobic process

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25. The glycolysis is regulated by

A) Pyruvate kinase

B) Phosphofructokinase

C) All of these

D) Hexokinase

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26. Reduced glutathione functions in R.B.Cs
to

A) Produce NADPH

B) Produce NADH

C) Reduce methemoglobin to hemoglobin

D) Reduce oxidizing agents such as H2O2

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27. Which of the following reactions is unique
to gluconeogenesis

A) Phosphoenol pyruvate pyruvate

B) Oxaloacetate phosphoenol pyruvate

C) Lactate Pyruvate

D) Glucose-6-phosphate Fructose-6-phosphate

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28. The conversion of pyruvate to acetyl CoA
and CO2

A) Depends on the coenzyme biotin

B) Involves the participation of lipoic acid

C) Occurs in the cytosol

D) Is reversible

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29. The more positive the E0, the greater the
tendency of the oxidant member of that
pair to

A) Lose electrons

B) Gain electrons

C) Lose and gain electrons

D) Lose (or) gain electrons

30 / 31

30. How many ATP molecules will be required
for conversion of 2-molecules of Lactic acid
to Glucose

A) 2

B) 6

C) 8

D) 4

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31. Glucokinase

A) None of these

B) Has a high km for glucose and hence is important in the phosphorylation of glucose primarily after ingestion of a carbohydrate rich meal

C) Is widely distributed and occurs in most mammalian tissues

D) Is widely distributed in Prokaryotes

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The average score is 40%

Carbohydrates Biochemistry Set 5

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