Page 1 of 1: MCQ "5"

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Question 1. Glycolysis:

(a) Occurs in the cell cytosol.
True False

(b) Can operate under both aerobic and anaerobic conditions.
True False

(c) Does not occur in red blood cells.
True False

(d) Contains three essentially irreversible reactions.
True False

(e) Under aerobic conditions, generates the net production of 12 molecules of ATP.
True False

Question 2. The reaction catalysed by phosphofructokinase-1 (PFK-1):

(a) Is an example of an isomerization reaction.
True False

(b) Catalyses the phosphorylation of fructose-6-phosphate.
True False

(c) Is the rate-limiting reaction of the glycolytic pathway.
True False

(d) Is allosterically inhibited by fructose 2,6-bisphosphate.
True False

(e) Is allosterically inhibited by ATP and citrate.
True False

Question 3. Regarding glucose metabolism:

(a) Under anaerobic conditions pyruvate is reduced to lactate, regenerating NAD+.
True False

(b) The malate-aspartate shuttle has a role in the regeneration of NAD+.
True False

(c) Net ATP yield from anaerobic glycolysis is two ATP.
True False

(d) Pyruvate kinase is regulated by reversible phosphorylation.
True False

(e) A deficiency of pyruvate kinase may result in a haemolytic anaemia
True False

Question 4. Acetyl CoA:

(a) Serves as a donor of acetyl groups in fatty acid synthesis.
True False

(b) Cannot be formed from protein.
True False

(c) Is used to make cholesterol and ketone bodies.
True False

(d) Allosterically activates pyruvate dehydrogenase.
True False

(e) Is carboxylated by pyruvate carboxylase to form malonyl CoA.
True False

Question 5. The TCA cycle:

(a) Operates under aerobic and anaerobic conditions.
True False

(b) Occurs in the mitochondrial matrix.
True False

(c) Does not occur in red blood cells.
True False

(d) Is an amphibolic pathway.
True False

(e) Each turn of the cycle produces three molecules of FADH2 and one molecule of NADH per mole of acetyl CoA oxidized.
True False

Question 6. Oxidative phosphorylation:

(a) Occurs in the inner mitochondrial space.
True False

(b) Involves the transfer of electrons from NADH or FADH2 down a series of electron carriers to molecular oxygen.
True False

(c) The oxidation of NADH by the et chain produces 1.5 ATP.
True False

(d) The oxidation of FADH2 by the et chain produces 1.5 ATP.
True False

(e) Is the process in which electron transport is coupled to the transport of protons across the inner mitochondrial membrane.
True False

Question 7. Regarding the components of the electron transport chain:

(a) Proton pumping occurs at complex I-NADH dehydrogenase.
True False

(b) Proton pumping occurs at complex II-succinate ubiquinone reductase.
True False

(c) Antimycin A inhibits electron transport at complex II.
True False

(d) Cyanide inhibits electron flow in complex IV-cytochrome oxidase.
True False

(e) Oligomycin is an uncoupler of the chain.
True False

Question 8. Gluconeogenesis:

(a) Occurs exclusively in the cell cytosol.
True False

(b) Usually occurs in muscle.
True False

(c) Is important in maintaining blood glucose concentration during early starvation.
True False

(d) Is activated by fructose 2,6-bisphosphate.
True False

(e) Allows fatty acids to be converted into glucose in net amounts.
True False

Question 9. Fructose:

(a) Entry into cells is insulin dependent.
True False

(b) Most dietary fructose is metabolized by the muscle.
True False

(c) In the liver, the first step of its metabolism is phosphorylation by fructokinase.
True False

(d) Is metabolized at a greater rate than glucose because it is a smaller molecule.
True False

(e) Excessive ingestion of fructose can result in lactic acidosis.
True False

Question 10. Regarding the pentose phosphate pathway:

(a) The net ATP yield from the pathway is six ATP.
True False

(b) It is located in mitochondria.
True False

(c) It generates reducing power as NADPH.
True False

(d) Glucose-6-phosphate dehydrogenase catalyses the rate-limiting step.
True False

(e) It produces five-carbon ribose sugars which can be used for nucleotide synthesis.
True False

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