Question

Explạin how CẠC intermediạtes cạn be used to feed biosynthetic pạthwạys ạnd how other cạtạbolic pạthwạys feed into the CẠC.

Answer 1

Answere :

Metabolic pathways fall into three categories:

1) Anabolic pathways are those involved in the synthesis of compounds. Anabolic pathways are endergonic. Example -Photosynthesis.

2) Catabolic pathways are involved in the breakdown of larger molecules, commonly involving oxidative reactions; they are exergonic, producing reducing equivalents and, mainly via the respiratory chain, ATP.

3) Amphibolic pathways occur at the “crossroads” of metabolism, acting as links between the anabolic and catabolic pathways. Example -Citric acid cycle.

Amphibolic Nature of the cycle :Citric acid cycle is amphibolic (both catabolic + anabolic) in nature.

The catabolic role :

1. It is the final pathway for the oxidation of sugars, fats, and proteins, because glucose, fatty acids and amino acids are all metabolized to acetyl-CoA.
2. It is the major source of energy for cells containing mitochondria.

The anabolic role:

The intermediates in the cycle provide precursors for many anabolic pathways.
For example:
1. Synthesis of fatty acids from citrate.
2. Synthesis of Some amino acids from α-ketoglutarate.
3. Synthesis of glucose by gluconeogenesis via oxaloacetate.