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MCB

MCB

Question 1 of 26

1

All of the following are true about Henderson-Hasselbalch equation except

Select one of the following:

  • If pKa < pH then A- > HA i.e. dissociated

  • if pKa > pH, then HA > A- i.e. not dissociated

  • When Concentration of A- and HA are equal then pH=pKa

  • None of the above

Explanation

Question 2 of 26

1

All of the following are sequence of events in the transport of bicarbonate

Select one of the following:

  • Tissues like liver generate CO2 by cellular respiration

  • CO2 + H2O in the presence of carbonic anhydrase in RBC results in H2CO3

  • H2CO3 dissociates into H+ and HCO3-

  • H+ is taken up by the Hemoglobin and HCO3- is exchanged for PO4-

Explanation

Question 3 of 26

1

All of the following regarding Oxy-Hb dissociation curve are true except?

Select one of the following:

  • Shift to the right means more O2 is released to the tissues

  • Low pH, high PCO2, increased H+ concentration and increased 2,3DPG all cause a shift to the right

  • Hemoglobin and Myoglobin both have the same type of curve

Explanation

Question 4 of 26

1

Proton binding by Hb reduces oxygen affinity is called the Bohr effect

Select one of the following:

  • True
  • False

Explanation

Question 5 of 26

1

Oxygen has >200 times greater affinity for Hb than CO

Select one of the following:

  • True
  • False

Explanation

Question 6 of 26

1

all of the following regarding enzymes are true except?

Select one of the following:

  • The velocity of all enzyme reactions is dependent on the concentration of the Substrate

  • The initial velocity of product formation (vi) proportional to Concentration of ES

  • Velocity continues to increase with increasing substrate concentration

Explanation

Question 7 of 26

1

In competitive inhibition Vmax is decreased and Km is unchanged, in noncompetitive inhibition Vmax remains unchanged and Km is changed

Select one of the following:

  • True
  • False

Explanation

Question 8 of 26

1

All of the following regarding allosteric enzyme are correct except

Select one of the following:

  • Regulation via allosterism can be more powerful since activators don't use catalytic site

  • Inhibitors have stronger effect than at active site

  • changes can be rapid

  • Allosteric enzyme has a sigmoid curve

  • None of the above

  • all of the above

Explanation

Question 9 of 26

1

All of the following are irreversible steps in Glycolysis except

Select one of the following:

  • Glucose to Glucose 6 phosphate

  • Fructose 6 phosphate to Fructose 1,6 bisphosphate

  • PEP to Pyruvate

  • Glyceraldehyde 3 phosphate to 1,3 Bisphosphoglycerate

Explanation

Question 10 of 26

1

All of the following regarding Glucokinase are true except?

Select one of the following:

  • low Km for glucose

  • High Vmax for glucose

  • indirectly inhibited by fructose 6 phosphate and stimulated by glucose

  • Not inhibited by Glucose 6 phosphate

  • Mutation of this enzyme cause MODY 2 and also play a role in gestational diabetes

Explanation

Question 11 of 26

1

All of the following about PFK1 are true except

Select one of the following:

  • PFK 1 irreversibly commits G6P to glycolysis

  • PFK1 is allosterically inhibited by ATP

  • PFK1 is allosterically activated by AMP and fructose 2,6 bisphosphate

  • none of the above

Explanation

Question 12 of 26

1

Pyruvate Kinase deficiency causes hemolytic anemia

Select one of the following:

  • True
  • False

Explanation

Question 13 of 26

1

All of the following are true about Warburg effect except?

Select one of the following:

  • Proliferating cells get ATP from glycolysis not Oxidative Phosphorylation

  • Glycolysis is up regulated by oncogenes

  • Damaged mitochondria so no TCA cycle only glycolysis

  • Works for all body cancers including brain

Explanation

Question 14 of 26

1

All of the following about PDC (pyruvate dehydrogenase complex) are true except

Select one of the following:

  • Co factor for E1 is B1, Cofactor for E2 is lipoic acid and cofactor for E3 is FAD/NAD

  • E1 is X linked

  • PDH deficiency causes lactic acidosis and a type of subacute necrotizing encephalomyelopathy (Leigh disease)

  • None of the above

Explanation

Question 15 of 26

1

Following all are the fates of pyruvate except

Select one of the following:

  • Transmination becomes Alanine

  • Dehydrogenation becomes acetyl CoA (by PDH in the presence of Oxygen)

  • In the absence of oxygen becomes lactate

  • Carboxylation to Oxaloacetate

  • none of the above

Explanation

Question 16 of 26

1

PDH kinase inactivates PDC

Select one of the following:

  • True
  • False

Explanation

Question 17 of 26

1

The only substrate level ATP production in TCA cycle is from succinyl CoA to succinate

Select one of the following:

  • True
  • False

Explanation

Question 18 of 26

1

TCA cycle produces NADH for OxPhos, OxPhos produces ATP

Select one of the following:

  • True
  • False

Explanation

Question 19 of 26

1

All of the following about ETC is correct except?

Select one of the following:

  • Complex I cofactor is NADH

  • Complex II - Cofactor FADH2

  • CoQ only component of ETC not protein bound

  • Complex III - cytochrome b-c1

  • ETC reduces NADH and FADH2

Explanation

Question 20 of 26

1

All of the following statements are true except

Select one of the following:

  • Rotenone is inhibitor of complex 1 in ETC

  • Inhibition of Complex 1 causes a decrease in proton gradient

  • Oligomycin is an ATP synthase inhibitor - which increases the proton gradient

  • 2,4 Dinitrophenol is an uncoupling agent - which increases proton gradient

Explanation

Question 21 of 26

1

The primary carbon-containing molecules that are substrates for gluconeogenesis are alanine from protein degradation, lactate from anaerobic glycolysis and glycerol from fat

Select one of the following:

  • True
  • False

Explanation

Question 22 of 26

1

All of the following are gluconeogenic enzymes except

Select one of the following:

  • Pyruvate carboxylase

  • PEP carboxykinase

  • Fructose 1,6 bisphosphatase

  • Glucose 6 phosphatase

  • None of the above

Explanation

Question 23 of 26

1

All of the following are true about HMP shunt

Select one of the following:

  • Provides a source of NADPH and ribose

  • Oxidative (irreversible) reaction generates NADPH

  • Non oxidative (reversible) reaction generated Ribose 5 phosphate

  • all of the above

  • 1 and 2 only

Explanation

Question 24 of 26

1

All of the following are true about Reactive Oxygen Species

Select one of the following:

  • SOD, Catalase and Glutathione are all the enzymes that are used as a defense against oxygen toxicity

  • OH radicle attacks the C=C polyunsaturated lipid in membrane which yields malondialdehyde

  • Free radical production is part of host defense, intended to destroy microorganism and tumor cells

  • All of the above

Explanation

Question 25 of 26

1

Acetaminphen

Select one of the following:

  • Normal amounts of which are sulphated or glucuronated for excretion

  • Excess is oxidized by Cyp 2E1 to toxic NAPQI

  • NAPQI cannot be metabolized

  • N acetyl cysteine is the treatment for acetaminophen toxicity

Explanation

Question 26 of 26

1

Ethanol

Select one of the following:

  • Dehydrogenated to Acetaldehyde by ADH which is then dehydrogenated by ALDH to acetyl CoA

  • Pyruvate is converted to lactate to generate NAD+ which can be used in the above dehydrogenase reactions as Hydrogen acceptor

  • Lactic acidosis, gout, hypoglycemia and hyperlipidemia are all acute effects of ethanol metabolism

  • all of the above are correct

Explanation

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