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) Requires oxidation/reduction of FAD

B) Requires the participation of biotin

C) Is inhibited by elevated level of insulin

D) Occurs exclusively in the cytosol

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2. 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) Keq is equal to 1

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

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3. 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) Pyruvate kinase catalyses an irreversible reaction

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

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

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

A) Malate dehydrogenase

B) Fumarase

C) Aconitase

D) Isocitrate dehydrogenase

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5. Glucokinase

A) Is widely distributed and occurs in most mammalian tissues

B) None of these

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) Is widely distributed in Prokaryotes

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6. The glycolysis is regulated by

A) All of these

B) Phosphofructokinase

C) Hexokinase

D) Pyruvate kinase

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

A) 2

B) 6

C) 4

D) 1

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8. 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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9. 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 electrons

D) Lose (or) gain electrons

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

A) GTP only

B) ITP only

C) None of these

D) GTP (or) ITP

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11. 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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12. 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) Succinic acid→ Fumarate

B) socitrate→ Oxaloacetate

C) Citric acid→ Isocitric acid

D) Succinylcat→ Succinic acid

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

A) 8

B) 6

C) 4

D) 2

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14. The conversion of pyruvate to acetyl CoA
and CO2

A) Involves the participation of lipoic acid

B) Occurs in the cytosol

C) Depends on the coenzyme biotin

D) Is reversible

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15. Cori cycle is

A) Synthesis of glucose

B) Both (A) & (B

C) reuse of glucose

D) uptake of glycose

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16. Phenylalanine is the precursor of

A) L-DOPA

B) Tyrosine

C) Histamine

D) Throxine

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17. 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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18. 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) Is inhibited by fructose 2, 6-bisphosphate

D) Uses fruitose-1-phosphate as substrate

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19. The reaction catalysed by phosphofructokinase

A) Is inhibited by fructose 2, 6-bisphosphate

B) Uses fruitose-1-phosphate as substrate

C) Is activated by high concentrations of ATP and citrate

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

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20. 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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21. Phenylalanine is the precursor of

A) Histamine

B) Tyrosine

C) Throxine

D) L-DOPA

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22. Glycogen is present in all body tissues
except

A) Kidney

B) Brain

C) Stomach

D) Liver

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23. 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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24. The free energy change, AG

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

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

C) Is equal to –RT in keq

D) Is equal to zero at equilibrium

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25. 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) Protons

D) Uncouplers

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

A) Acetyl CoA

B) Glycerol

C) α-ketoglutarate

D) Lactate

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27. 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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28. An uncoupler of oxidative phosphorylation such as dinitropheno

A) Allow electron transport to proceed without ATP synthesis

B) Specially inhibits cytochrome b

C) Inhibits electron transport without impairment of ATP synthesis

D) Inhibits electron transport and ATP synthesis

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

A) Decreased concentration of AMP

B) Decreased oxidation of pyruvate of CO2 and water

C) An increased conversion of pyruvate to lactate

D) A decreased NADH/NAD+ ratio

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

A) Glyceraldehyde-3-p dehydrogenase

B) Glucose-6-p-dehydrogenase

C) Phosphogluconate dehydrogenase

D) Transketolase

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31. 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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The average score is 40%

Carbohydrates Biochemistry Set 5

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