Question

Oxidative phosphorylation refers to

• A. synthesis of $\mathrm{ATP}$ during photosynthesis
• B. synthesis of $\mathrm{NADPH}$ during photosynthesis
• C. synthesis of $\mathrm{ATP}$ in respiration
• D. synthesis of $\mathrm{NADH}$ in respiration

Answer 1

The correct option is C synthesis of $\mathrm{ATP}$ in respiration

During respiration, oxidative phosphorylation refers to the synthesis of $\mathrm{ATP}$ with the energy obtained from the oxidation-reduction processes that happen at the time of breakdown of glucose.

When the electrons from $\mathrm{NADH}$ or ${\mathrm{FADH}}_2$ pass from one carrier to another via complex I to IV in the electron transport chain (ETC), they are coupled to $\mathrm{ATP}$ synthase (complex V) for the production of $\mathrm{ATP}$ from $\mathrm{ADP}$ and inorganic phosphate.

It is this energy which is obtained from oxidation-reduction processes that is utilised for the phosphorylation of $\mathrm{ADP}$ to produce $\mathrm{ATP}$. It is for this reason that the process is called oxidative phosphorylation.