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) Decreased oxidation of pyruvate of CO2 and water

B) An increased conversion of pyruvate to lactate

C) A decreased NADH/NAD+ ratio

D) Decreased concentration of AMP

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2. The synthesis of glucose from pyruvate
by gluconeogenesis

A) Requires the participation of biotin

B) Occurs exclusively in the cytosol

C) Requires oxidation/reduction of FAD

D) Is inhibited by elevated level of insulin

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3. Phenylalanine is the precursor of

A) L-DOPA

B) Histamine

C) Throxine

D) Tyrosine

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4. Cori cycle is

A) uptake of glycose

B) reuse of glucose

C) Synthesis of glucose

D) Both (A) & (B

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5. Phenylalanine is the precursor of

A) Tyrosine

B) Throxine

C) L-DOPA

D) Histamine

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

A) GTP only

B) None of these

C) ITP only

D) GTP (or) ITP

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7. The conversion of pyruvate to acetyl CoA
and CO2

A) Occurs in the cytosol

B) Depends on the coenzyme biotin

C) Involves the participation of lipoic acid

D) Is reversible

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8. The reaction catalysed by phosphofructokinase

A) Is inhibited by fructose 2, 6-bisphosphate

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

C) Is activated by high concentrations of ATP and citrate

D) Uses fruitose-1-phosphate as substrate

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9. Glucokinase

A) None of these

B) Is widely distributed and occurs in most mammalian tissues

C) Is widely distributed in Prokaryotes

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

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10. 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) Succinylcat→ Succinic acid

C) socitrate→ Oxaloacetate

D) Succinic acid→ Fumarate

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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 without impairment of ATP synthesis

B) Inhibits electron transport and ATP synthesis

C) Specially inhibits cytochrome b

D) Allow electron transport to proceed without ATP synthesis

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

A) α-ketoglutarate

B) Lactate

C) Acetyl CoA

D) Glycerol

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

A) 6

B) 2

C) 8

D) 4

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15. The reaction catalysed by phosphofructokinase

A) Uses fruitose-1-phosphate as substrate

B) Is activated by high concentrations of ATP and citrate

C) Is inhibited by fructose 2, 6-bisphosphate

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

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

A) Aconitase

B) Malate dehydrogenase

C) Fumarase

D) Isocitrate dehydrogenase

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

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

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

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

D) Hemolytic anemia

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

A) 6

B) 1

C) 2

D) 4

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

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

D) Pyruvate kinase catalyses an irreversible reaction

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

A) Produce NADPH

B) Reduce oxidizing agents such as H2O2

C) Produce NADH

D) Reduce methemoglobin to hemoglobin

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22. The free energy change, AG

A) Is equal to –RT in keq

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

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

D) Is equal to zero at equilibrium

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23. Glycogen is present in all body tissues
except

A) Brain

B) Stomach

C) Kidney

D) Liver

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

A) Reduce oxidizing agents such as H2O2

B) Produce NADH

C) Produce NADPH

D) Reduce methemoglobin to hemoglobin

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

A) Transketolase

B) Glyceraldehyde-3-p dehydrogenase

C) Phosphogluconate dehydrogenase

D) Glucose-6-p-dehydrogenase

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

A) Protons

B) Uncouplers

C) Electrons

D) All of these

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

A) Gain electrons

B) Lose and gain electrons

C) Lose (or) gain electrons

D) Lose electrons

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28. The glycolysis is regulated by

A) All of these

B) Phosphofructokinase

C) Hexokinase

D) Pyruvate kinase

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

A) CO2

B) Protein

C) CO2 and ATP

D) ATP, Protein and CO2

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30. 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 is amphibolic in nature

C) It occurs in cytosol

D) It is an anaerobic process

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31. Which of the following reactions is unique
to gluconeogenesis

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

B) Lactate Pyruvate

C) Oxaloacetate phosphoenol pyruvate

D) Phosphoenol pyruvate pyruvate

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The average score is 40%

Carbohydrates Biochemistry Set 5

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