Question

QUESTION 65 Free energy (delta G) is higher during the citric acid cycle than during glycolysis. Despite this, only two molecules of ATP will be generated in the krebs cycle. Most of the remaining free energy that is released during the krebs cycle will be O a. Used to synthesize GTP O b. Converted into kinetic energy O c.Lost as heat d. Used to reduce pyruvate Oe. Used to reduce electron carriers such as NADH and FADH2

Answer 1

Answer: e. Used to reduce electron carriers such as NADH and FADH2.

Explanation: During Krebs cycle (Citric acid cycle), Nicotinamide adenine dinucleotide (NAD+) is reduced to NADH + H+ in the process and Flavin adenine dinucleotide (FAD) is reduced and forms FADH2 with the help of the free energy.

- These electron carriers’ molecules get converted into energy (ATP) when they enter electron transport chain.

- That is why though more free energy is produced during Citric acid cycle, only 2 molecules of ATP are generated.

Incorrect options:

a. Used to synthesize GTP: Synthesis of GTP involves NADH but not all free energy is utilized for the same.

b. Converted into kinetic energy: Energy stored in organic molecules. Through the process called cellular respiration, this potential energy is converted into kinetic energy in order to make cell work.

c. Lost as heat: As the whole process is exergonic reaction but only some energy is lost as heat.

d. Used to reduce pyruvate: Pyruvate gets reduced to lactic acid when there is oxidation of NADH to NAD+. This process occurs when oxygen supply is depleted (This occurs during exercise). This pyruvate gets converted into acetyl CoA when oxygen supply back.