Question

If carbohydrates are unavailable for cellular respiration, other organic molecules can be broken down and enter the cellular respiration process at the appropriate spot. Proteins can be broken down into a variety of amino acids. Some amino acids can be converted into glutamate which can then be converted into alpha- ketoglutarate. State which steps of the cellular respiration pathway, lead to the generation of the energy molecules. State the TOTAL number of ATP molecules the ONE of these converted alpha-ketoglutarate molecules can produce and explain how all the ATP molecules are generated.

Answer 1

In cellular respiration, various steps which generate energy are glycolysis, pyruvate dehydrogenase complex, Kreb's cycle etc.

These steps generate energy in form of ATP or reducing powers such as NADH and FADH2.

Reducing powers are fed to electron transport chain which takes place in inner mitochondrial membrane and pumps protons from matrix to intermembrane space. These protons then move along concentration gradient back to the matrix via ATPase complex and generate ATP.

Amino acid that converts to glutamate undergo transamination to form alpha-ketoglutarate which enters the Kreb cycle.

Following steps of Kreb's cycle occur :

Total ATPs produced per molecule of glutamate are 9.