Question

Complete oxidation of glucose to CO2 involves two different mechanisms for synthesizing ATP, oxidative phosphorylation and substrate-level phosphorylation. Which is true of substrate-level phosphorylation?
a. ATP is generated indirectly through the transfer of high-energy electrons from electron carriers to an electron transport chain.
b. Most of the ATP generated in cellular respiration is generated by substrate-level phosphorylation.
c. An enzyme catalyzes the transfer of a phosphate group to ADP from an organic molecule to form ATP.
d. ATP is generated by release of energy from the electron carriers NADH and FADH2.

Answer 1

Answer: C

Explanation:

In substrate level phosphorylation energy is trapped directly from the substrate, without the help of the complicated electron transport chain reactions.

Substrate-level phosphorylation refers to the formation of ATP from ADP by directly phosphorylating ADP from a high energy substrate catalyze by an enzyme.

But when energy is trapped by oxidation of reducing equivalents such as NADH, it is called oxidative phosphorylation.

Examples of substrate level phosphorylation in glycolysis include conversion of 1, 3-Bisphospho glycerate to 3-Bisphospho glycerate and conversion of phospho enol pyruvate to pyruvate