Answer:
d. Reaction 7 of the citric acid cycle.Fumarate <--> Malate)
Step-by-step explanation:
N oxidation reaction is one that involves the removal of electrons or hydrogen atoms or the addition of oxygen; whereas a reduction reaction involves the addition of electrons or hydrogen atoms or the removal of oxygen.
Considering the given option below:
a. Reaction 6 of glycolysis (glyceraldehyde 3-phosphate <--> 1,3 Bisphosphoglycerate) is an oxidation reaction involving the addition of an oyyegen atom in the form of a phosphate to C-1 of glyceraldehyde-3--phosphate to form 1,3-bisphosphoglycerate
b. Reaction 4 of the citric acid cycle (alpha-ketoglutarate <--> succinyl CoA
) is an oxidation reaction in which NAD⁺ sreves as an electron acceptor (removing a hydrogen atom as a hydride) in the decarboxylation of alpha-ketoglutarate to form succinyl CoA and CO₂
c. Reaction 3 of the citric acid cycle (Isocitrate <--> alpha-ketoglutarate) is an oxidation reaction in which isocitrate is oxidized to alpha-ketoglutarate by hydride transfer to NAD⁺ or NADP⁺.
d. Reaction 7 of the citric acid cycle.Fumarate <--> Malate) is a hydration reaction in which fumarate is hydrated (water is added in the form of OH⁻ and H⁺) to malate.
e. Reaction 5 of the PDH complex (E2-dihydrolipoamide acid <--> E2-lipoamide) is an oxidation reaction involving the removal of electrons in the form of hydride ions which are transferred to FAD from E2-dihydrolipoamide acid to form E2-lipoamide.