Carbohydrates Biochemistry Set 5

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Biochemistry (Carbohydrates And Carbohydrate Metabolism Set 5)

MCQ

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

A) Transketolase

B) Phosphogluconate dehydrogenase

C) Glucose-6-p-dehydrogenase

D) Glyceraldehyde-3-p dehydrogenase

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

A) Decreased oxidation of pyruvate of CO2 and water

B) A decreased NADH/NAD+ ratio

C) An increased conversion of pyruvate to lactate

D) Decreased concentration of AMP

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3. Glycogen is present in all body tissues
except

A) Liver

B) Stomach

C) Brain

D) Kidney

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4. The free energy change, AG

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

B) Is equal to zero at equilibrium

C) Is equal to –RT in keq

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

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5. 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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6. 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 (or) gain electrons

D) Lose and gain electrons

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7. The reaction catalysed by phosphofructokinase

A) Is inhibited by fructose 2, 6-bisphosphate

B) Is activated by high concentrations of ATP and citrate

C) Uses fruitose-1-phosphate as substrate

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

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8. 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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9. The glycolysis is regulated by

A) All of these

B) Phosphofructokinase

C) Hexokinase

D) Pyruvate kinase

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

A) Isocitrate dehydrogenase

B) Fumarase

C) Aconitase

D) Malate dehydrogenase

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12. Cori cycle is

A) uptake of glycose

B) Both (A) & (B

C) reuse of glucose

D) Synthesis of glucose

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13. 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 exhibit ATPase activity

C) ) It can bind molecular O2

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

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

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

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

C) Hemolytic anemia

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

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

A) Acetyl CoA

B) α-ketoglutarate

C) Glycerol

D) Lactate

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

A) All of these

B) Electrons

C) Uncouplers

D) Protons

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17. Phenylalanine is the precursor of

A) Histamine

B) Tyrosine

C) L-DOPA

D) Throxine

18 / 31

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

A) 4

B) 6

C) 8

D) 2

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19. Glucokinase

A) Is widely distributed in Prokaryotes

B) Is widely distributed and occurs in most mammalian tissues

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

D) None of these

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

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

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

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

D) Pyruvate kinase catalyses an irreversible reaction

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21. Under standard conditions

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

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

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

D) Keq is equal to 1

22 / 31

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

A) Produce NADH

B) Produce NADPH

C) Reduce methemoglobin to hemoglobin

D) Reduce oxidizing agents such as H2O2

23 / 31

23. 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) Succinic acid→ Fumarate

C) Succinylcat→ Succinic acid

D) socitrate→ Oxaloacetate

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24. Which of the following reactions is unique
to gluconeogenesis

A) Oxaloacetate phosphoenol pyruvate

B) Phosphoenol pyruvate pyruvate

C) Lactate Pyruvate

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

25 / 31

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

A) It is an anaerobic process

B) It is amphibolic in nature

C) It occurs in cytosol

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

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26. Phenylalanine is the precursor of

A) Throxine

B) Tyrosine

C) L-DOPA

D) Histamine

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

A) ITP only

B) GTP only

C) GTP (or) ITP

D) None of these

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

A) 4

B) 6

C) 2

D) 1

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29. The synthesis of glucose from pyruvate
by gluconeogenesis

A) Requires the participation of biotin

B) Is inhibited by elevated level of insulin

C) Requires oxidation/reduction of FAD

D) Occurs exclusively in the cytosol

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

A) Protein

B) CO2

C) CO2 and ATP

D) ATP, Protein and CO2

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31. The reaction catalysed by phosphofructokinase

A) Is inhibited by fructose 2, 6-bisphosphate

B) Is activated by high concentrations of ATP and citrate

C) Uses fruitose-1-phosphate as substrate

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

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The average score is 40%

Carbohydrates Biochemistry Set 5

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