Question

Explain how the citric acid cycle connects to other metabolic pathways, both catabolic and anabolic. List as many examples as possible.

Answer 1

Citric acid cycle has both catabolic and anabolic reactions.

• Catabolic – Energy from oxidation of acetyl CoA is stored in reduced coenzymes.
• Anabolic – Several intermediates are precursors in biosynthetic pathways.

The connection with Citric acid cycle and metabolic pathways is that citric acid cycle degrades acetyl CoA to yield carbon dioxide, and energy, which is later used to produce NADH, H+ and FADH.

The citric acid cycle is a common pathway in the oxidation of fuel molecules. In stage 3 of metabolism, citric acid is a common catabolic intermediate in the form of acetylCoA. This is why the citric acid cycle is called a central metabolic pathway.

Cells use the oxygen expelled by photosynthesis to extract more energy from the sugar molecules using the citric acid cycle.