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Q.1-Out of the following respiratory chain components indicate which  one is a mobile carriers of electrons?

a) Cytochrome oxidase

b) NADH-Q reductase

c) Ubiquinone

d) Succinate dehydrogenase                                             

Q.2-Choose the incorrect statement about redox potential

a) The redox potential of a system (E0) is usually compared with the potential of the hydrogen electrode

b) The components of electron transport chain are organized in terms of their redox potential.

c) NADH/NAD+ redox pair has the least redox potential of -0.42 volts

d) Oxygen/H2O redox pair has the highest redox potential of +.82 volts

Q.3-All are flavoproteins except one, choose the odd one out

a) Xanthine oxidase

b) NADH dehydrogenase –Q reductase

c) Succinate dehydrogenase

d) Cytochrome c                                                               

Q.4-All except one are incorrect about oxidases-

a) Oxidases catalyze reactions involving hydrogen peroxide.

b) Oxidases catalyze reaction using oxygen as a hydrogen acceptor

c) Oxidases catalyze  reactions using Niacin as coenzyme

d) Oxidases catalyze reactions of direct incorporation of oxygen in to the substrate

Q.5-All of the following are NAD+ requiring enzymes except one –

a) Acyl co A dehydrogenase

b) Glyceraldehyde-3-P dehydrogenase

c) Pyruvate dehydrogenase complex

d) Malate dehydrogenase

Q.6-One out of the following enzymes can utilize both NAD+ and NADP+as a coenzyme

a) Aldehyde dehydrogenase

b) Alcohol dehydrogenase

c) Glutamate dehydrogenase

d) Glycerol-3-P dehydrogenase

Q.7-Which out of the following components is not a haemo protein?

a) Catalase

b) Peroxidase

c) Ubiquinone

d) Cytochrome c                                                              

Q.8-Dioxygenases catalyze the incorporation of both atoms of oxygen in to the substrate. Which out of the following is a dioxygenase?

a) Tryptophan pyrrolase

b) Lactate dehydrogenase

c) Cytochrome oxidase

d) L- amino acid oxidase                                                  

Q.9 -Which of the components of electron transport chain does not contain Iron sulfur center?

a) NADH dehydrogenase complex

b) Cytochrome a-a3 oxidase

c) Succinate dehydrogenase

d) Cytochrome bc1-c reductase                                        

Q.10-A child has accidentally ingested a chemical and has presented with high fever.The chemical is known to affect ATP formation in electron transport chain,which out of the following could cause the similar manifestations

a) Cyanide

b) Malonate

c) 2,4 dinitrophenol

d) Rotenone                                                                    

Q.11-A 32- year female working in a laboratory consumed cyanide and was rushed to hospital. She was declared dead upon reaching the hospital. Cyanide is a known inhibitor of Electron Transport chain (ETC). Which complex of ETC might have been inhibited?

a) Complex I

b) Complex II

c) Complex III

d) Complex IV        

Q.12-The enzymes of mitochondrial matrix include all except

a) Enzymes of fatty acid oxidation

b) Creatine kinase

c) Enzymes of TCA cycle

d) Pyruvate dehydrogenase complex

Q.13-Patients with inherited defects of mitochondria involving components of the respiratory chain and oxidative phosphorylation present with all except

a) Myopathy

b) Lactic acidosis

c) Encephalopathy

d) Hepatomegaly

Q.14-The inner mitochondrial membrane is rich in which of the following phospholipids?

a) Cardiolipin

b) Lecithin

c) Cephalin

d) None of the above                                                       

Q.15-All are true about ATP synthase complex, except

a) F1projects into the inter membranous space

b) Fspans the membrane and forms a proton channel.

c) Fis inhibited by Oligomycin

d) F1contains the phosphorylation mechanism                     

Q.16-The energy yield during the conversion of succinate to Fumarate is-

a) 2ATP

b) 1ATP

c) 3ATP

d) No ATP                                                                     

Q.17-Which of the following best describes the biochemical basis of hyperthermia associated with Aspirin toxicity

a) Increased fatty acid oxidation

b) Increased muscular activity

c) Elevated consumption of ATP to support muscle contraction

d) Uncoupling of oxidative phosphorylation                       

Q.18-The electron flow from complex I to complex III is through

a) Cytochrome c

b) Ubiquinone

c) Complex II

d) Complex IV

Q.19-Which of the following best describes the toxicity associated with Atractyloside

a) Acts as an inhibitor of ETC

b) Acts as an uncoupler

c) Acts as an inhibitor of ATP/ADP transporter

d) Inactivates ATP synthase complex

Q.20- For each H2O molecule formed in ETC around ———– protons are pumped into inter membranous space

a) 4

b) 2

c) 10

d) None of the above

Q.21- Which one of the following enzymes catalyzes substrate level phosphorylation in TCA cycle

a) Malate dehydrogenase

b) Succinate Thiokinase

c) Succinate dehydrogenase

d) Alpha keto glutarate dehydrogenase complex

Q.22- Which of the following occurs in non shivering thermogenesis?

a) Glucose is oxidized to lactate

b) Fatty acids uncouple oxidative phosphorylation

c) ATP is spent for heat production

d) Glycogen is excessively degraded

Q.23- One out of the following is an inhibitor of complex I

a) Rotenone

b) H2S

c) BAL

d) CN

Q.24- Which out of the following statements concerning the components of electron transport chain is true?

a) Oxygen directly oxidizes Cytochrome c

b) Succinate dehydrogenase directly reduces Cytochrome c

c) All of the components are embedded in the inner mitochondrial membrane

d) Cyanide does not inhibit proton pumping but inhibits ETC

Q.25- The free energy released during the transport of a pair of electrons in electron transport chain is

a) 7.3 Kcal/mol

b) 52.6 Kcal/mol

c) 21.9 Kcal/mol

d) None of the above

Key to answers

1)- (c), 2)-(c), 3)- (d), 4)- (b), 5)- (a), 6)- (c), 7)- (c), 8)- (a), 9)- (b),10)- (c),11)- (d), 12)- (b),13)- (d),14)- (a),

15) (a), 16)- (a),17)- (d),18)- (b),19)- (c), 20)-(c), 21)- (b), 22)- (b), 23)- (a), 24)- (d), 25)- (b). 


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