Question

Oxidation of glyceraldehyde phosphate is accompanied by

• A. Oxidation of $NA{D}^{+}$
• B. Substrate level phosphorylation
• C. Reduction of $NA{D}^{+}$
• D. Oxidative phosphorylation

Answer 1

The correct option is C Reduction of $NA{D}^{+}$

Glyceraldehyde phosphate formed in the fourth step of glycolysis undergoes phosphorylation and dehydrogenation and gets converted into 1,3- diphosphoglyceric acid. In phosphorylation 3- phosphoglyceraldehyde combines with phosphate group derived from inorganic phosphoric acid found in cytosol forming 1,3- diphosphoglyceric acid. In dehydrogenation, a pair of hydrogen atoms separate from a molecules of 3-phosphoglyceraldehyde. This separation releases a large amount of energy which gets stored in newly formed phosphate bond of 1, 3 diphosphoglyceric acid making it high energy bond. Out of 2 hydrogen atoms which get separated from 3-phosphoglyceric acid, one complete hydrogen atom with one proton and electron and one additional electron are picked up by NAD+ which gets reduced to NADH. The remaining one hydrogen proton remains free in the cytosol. NADH is high energy substance carrying the rest of the energy released by separation of hydrogen atoms.

Thus, the correct answer is option C.