Question

The intermediates of Krebs cycle forms
(a) Nucleotides
(b) Amino acids
(c) Cytochrome
(d) All of the above

Answer 1

Hint: In the citric acid cycle all the intermediates (e.g. citrate, iso-citrate, alpha-ketoglutarate, succinate, fumarate, malate, and oxaloacetate) are regenerated during each turn of the cycle.

Complete answer:Krebs cycle is also known as Citric Acid Cycle or Tricarboxylic Acid Cycle. It is used to oxidize the pyruvate formed during the glycolysis into carbon dioxide and water. It also oxidizes acetyl CoA which arises from breakdown of carbohydrate, lipid, and protein.Intermediate compounds formed during Krebs cycle are used for the synthesis of amino acids, nucleotides, chlorophyll, cytochromes and fats.

Oxaloacetate forms aspartate and asparagine amino acids. Alpha-ketoglutarate forms glutamine, proline and arginine amino acids.
Amino acids aspartate and glutamine are used to form the purines. Amino acid aspartate is used to form the pyrimidines. Intermediate succinyl CoA forms chlorophyll and cytochromes.

So,the correct answer is 'All of the above’

Note: The cycle of citric acid is a key metabolic pathway which connects the metabolism of carbohydrates , fats and proteins. The cycle reactions are carried out of two molecules each of carbon dioxide and water by eight enzymes that fully oxidize acetate (a two carbon molecule), in the form of acetyl-CoA.