In humans, after a glucose molecule has been fully metabolized by the aerobic re
ID: 100752 • Letter: I
Question
Explanation / Answer
1) After a glucose molecule has been completely metabolized by aerobic respiration, following end products are formed :
C6H12O6 + O2 -> CO2 + H2O + 38 ATP
Out of the products, water and energy can never be excretory products but accumulation of carbon dioxide in body has several adverse effects.
So, the answer is (a). CO2.
2) Pyruvate is the product of glycolysis in cell cytoplasm so, option (b) is not possible.
Succinate dehydrogenase is an enzyme complex of citric acid cycle. So, (e) is not the answer. Glyceraldehyde phosphate dehydrogenase converts glucose into 3 carbon compounds. It, (d) is not the answer.
Pyruvate kinase catalyzes the last step of glycolysis. It yields ATP and is not the rate limiting step of glycolysis.
Phosphofructokinase (PFK) is the key regulatory enzyme of glycolysis. It can be inhibited by allosteric inhibition by excess fructose 1,6 bisphosphate and high ATP/AMP ratio. So. (a) is the answer.
3) Pyruvate and succinate dehydrogenase is not the answer for reasons given in answer (2).
PFK produces fructose 1,6 bis phosphate and pyruvate kinase yields ATP.
Glyceraldehyde phosphate dehydrogenase converts glyceraldehyde 3 phosphate to 1,3 diphosphoglycerate. It catalyzes both phosphorylation and reduction of NAD+ to NADH. So, (d) is the answer.
4) PFK, pyruvate kinase and glyceraldehyde phosphate dehydrogenase are enzymes of glycolysis. Pyruvate is the product of glycolysis in cell cytoplasm. So, (a), (b), (c), (d) is not the answer.
Succinate dehydrogenase is an enzyme complex in the inner mitochondrial membrane which takes part in both TCA cycle and electron transport chain.
So, (e) is the answer.
5) The given structure is of Acetyl coenzyme A with acetyl group present at one end which has been highlighted with dark shade. So, (c) is the answer.