Respiration in Plants Question 34
34. Which statement is wrong for Krebs’ cycle ?
[2017]
(a) There is one point in the cycle where $FAD^{+}$is reduced to $FADH_2$
(b) During conversion of succinyl CoA to succinic acid, a molecule of GTP is synthesised
(c) The cycle starts with condensation of acetyl group (acetyl CoA) with pyruvic acid to yield citric acid
(d) There are three points in the cycle where $NAD^{+}$is reduced to $NADH+H^{+}$
Show Answer
Answer : c
Hints & Solutions
(c) Krebs cycle begins with condensation of acetyl CoA (2C) with oxaloacetic acid (4C) to form citric acid (6C). The citric acid cycle is regulated primarily by the concentration of ATP and NADH. The key control points are the enzymes isocitrate dehydrogenase and $\alpha$-ketoglutarate dehydrogenase. $\alpha$-Ketoglutarate dehydrogenase is inhibited by succinyl CoA and NADH, the products of the reaction that it catalyzes.
