Carbohydrates Biochemistry Set 5

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Biochemistry (Carbohydrates And Carbohydrate Metabolism Set 5)

MCQ

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

A) A decreased NADH/NAD+ ratio

B) Decreased oxidation of pyruvate of CO2 and water

C) Decreased concentration of AMP

D) An increased conversion of pyruvate to lactate

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

A) 1

B) 4

C) 2

D) 6

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3. The conversion of pyruvate to acetyl CoA
and CO2

A) Depends on the coenzyme biotin

B) Is reversible

C) Involves the participation of lipoic acid

D) Occurs in the cytosol

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

A) ITP only

B) GTP only

C) None of these

D) GTP (or) ITP

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6. Cori cycle is

A) Both (A) & (B

B) uptake of glycose

C) reuse of glucose

D) Synthesis of glucose

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

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

B) It occurs in cytosol

C) It is amphibolic in nature

D) It is an anaerobic process

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8. The free energy change, AG

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

B) Is equal to zero at equilibrium

C) Is equal to –RT in keq

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

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

A) Protein

B) CO2

C) ATP, Protein and CO2

D) CO2 and ATP

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10. 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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11. 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 free energy change ∆G°, is equal to 0

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

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12. 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 and occurs in most mammalian tissues

C) None of these

D) Is widely distributed in Prokaryotes

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13. An uncoupler of oxidative phosphorylation such as dinitropheno

A) Allow electron transport to proceed without ATP synthesis

B) Inhibits electron transport without impairment of ATP synthesis

C) Specially inhibits cytochrome b

D) Inhibits electron transport and ATP synthesis

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

A) Produce NADPH

B) Reduce methemoglobin to hemoglobin

C) Reduce oxidizing agents such as H2O2

D) Produce NADH

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15. 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 located on the matrix side of the inner mitochondrial membrane

B) It can exhibit ATPase activity

C) It is inhibited by oligomycin

D) ) It can bind molecular O2

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16. The reaction catalysed by phosphofructokinase

A) Uses fruitose-1-phosphate as substrate

B) Is activated by high concentrations of ATP and citrate

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

D) Is inhibited by fructose 2, 6-bisphosphate

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17. Which of the following reactions is unique
to gluconeogenesis

A) Glucose-6-phosphate Fructose-6-phosphate

B) Phosphoenol pyruvate pyruvate

C) Lactate Pyruvate

D) Oxaloacetate phosphoenol pyruvate

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

A) Glycerol

B) Lactate

C) Acetyl CoA

D) α-ketoglutarate

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19. Phenylalanine is the precursor of

A) Throxine

B) L-DOPA

C) Tyrosine

D) Histamine

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20. Phenylalanine is the precursor of

A) Throxine

B) L-DOPA

C) Tyrosine

D) Histamine

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

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

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

C) Hemolytic anemia

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

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

A) 6

B) 8

C) 4

D) 2

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

A) Malate dehydrogenase

B) Fumarase

C) Isocitrate dehydrogenase

D) Aconitase

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

A) All of these

B) Protons

C) Electrons

D) Uncouplers

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

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

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

C) Pyruvate kinase catalyses an irreversible reaction

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

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26. Glycogen is present in all body tissues
except

A) Kidney

B) Brain

C) Liver

D) Stomach

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27. The glycolysis is regulated by

A) Hexokinase

B) Pyruvate kinase

C) All of these

D) Phosphofructokinase

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28. 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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29. The reaction catalysed by phosphofructokinase

A) Uses fruitose-1-phosphate as substrate

B) Is activated by high concentrations of ATP and citrate

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

D) Is inhibited by fructose 2, 6-bisphosphate

30 / 31

30. 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

31 / 31

31. 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) Succinylcat→ Succinic acid

C) Citric acid→ Isocitric acid

D) Succinic acid→ Fumarate

Your score is

The average score is 40%

Carbohydrates Biochemistry Set 5

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