Carbohydrates Biochemistry Set 5

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Biochemistry (Carbohydrates And Carbohydrate Metabolism Set 5)

MCQ

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1. An uncoupler of oxidative phosphorylation such as dinitropheno

A) Allow electron transport to proceed without ATP synthesis

B) Inhibits electron transport and ATP synthesis

C) Specially inhibits cytochrome b

D) Inhibits electron transport without impairment of ATP synthesis

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

A) Reduce methemoglobin to hemoglobin

B) Reduce oxidizing agents such as H2O2

C) Produce NADH

D) Produce NADPH

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3. 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 an anaerobic process

D) It is amphibolic in nature

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

A) Gain electrons

B) Lose (or) gain electrons

C) Lose and gain electrons

D) Lose electrons

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

A) GTP only

B) GTP (or) ITP

C) ITP only

D) None of these

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6. Phenylalanine is the precursor of

A) L-DOPA

B) Throxine

C) Tyrosine

D) Histamine

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

A) CO2 and ATP

B) CO2

C) Protein

D) ATP, Protein and CO2

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8. The conversion of pyruvate to acetyl CoA
and CO2

A) Is reversible

B) Occurs in the cytosol

C) Involves the participation of lipoic acid

D) Depends on the coenzyme biotin

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9. Phenylalanine is the precursor of

A) Tyrosine

B) Histamine

C) L-DOPA

D) Throxine

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

A) Reduce oxidizing agents such as H2O2

B) Reduce methemoglobin to hemoglobin

C) Produce NADH

D) Produce NADPH

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

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

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

A) An increased conversion of pyruvate to lactate

B) Decreased oxidation of pyruvate of CO2 and water

C) Decreased concentration of AMP

D) A decreased NADH/NAD+ ratio

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13. The free energy change, AG

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

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

C) Is equal to –RT in keq

D) Is equal to zero at equilibrium

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

A) Isocitrate dehydrogenase

B) Fumarase

C) Malate dehydrogenase

D) Aconitase

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15. The reaction catalysed by phosphofructokinase

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

B) Uses fruitose-1-phosphate as substrate

C) Is inhibited by fructose 2, 6-bisphosphate

D) Is activated by high concentrations of ATP and citrate

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16. Cori cycle is

A) Both (A) & (B

B) uptake of glycose

C) reuse of glucose

D) Synthesis of glucose

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17. The synthesis of glucose from pyruvate
by gluconeogenesis

A) Is inhibited by elevated level of insulin

B) Requires the participation of biotin

C) Occurs exclusively in the cytosol

D) Requires oxidation/reduction of FAD

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18. The glycolysis is regulated by

A) All of these

B) Pyruvate kinase

C) Hexokinase

D) Phosphofructokinase

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

A) It can exhibit ATPase activity

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

C) ) It can bind molecular O2

D) It is inhibited by oligomycin

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20. The reaction catalysed by phosphofructokinase

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

B) Uses fruitose-1-phosphate as substrate

C) Is activated by high concentrations of ATP and citrate

D) Is inhibited by fructose 2, 6-bisphosphate

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

A) 1

B) 4

C) 6

D) 2

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22. Glycogen is present in all body tissues
except

A) Brain

B) Kidney

C) Stomach

D) Liver

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

A) Protons

B) Electrons

C) All of these

D) Uncouplers

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24. Which of the following reactions is unique
to gluconeogenesis

A) Lactate Pyruvate

B) Phosphoenol pyruvate pyruvate

C) Oxaloacetate phosphoenol pyruvate

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

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

A) α-ketoglutarate

B) Lactate

C) Glycerol

D) Acetyl CoA

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

A) 6

B) 8

C) 2

D) 4

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27. Glucokinase

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

B) Is widely distributed in Prokaryotes

C) None of these

D) Is widely distributed and occurs in most mammalian tissues

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

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

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

C) Pyruvate kinase catalyses an irreversible reaction

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

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29. 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) Citric acid→ Isocitric acid

B) socitrate→ Oxaloacetate

C) Succinic acid→ Fumarate

D) Succinylcat→ Succinic acid

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30. Under standard conditions

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

B) Keq is equal to 1

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

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

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

A) Glucose-6-p-dehydrogenase

B) Transketolase

C) Glyceraldehyde-3-p dehydrogenase

D) Phosphogluconate dehydrogenase

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The average score is 40%

Carbohydrates Biochemistry Set 5

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