The amphibolic pathway is defined as a biochemical pathway which involves both anabolic and catabolic process.

• The respiration biochemical process has been conventionally considered to be a catabolic pathway as it comprises of the breakdown of substrates. But the breakdown of substrates serves as a part of the synthesis of other substrates.

• The fatty acids when respired are broken down into Acetyl CoA. Similarly, glycerol also enters a biochemical pathway and gets broken down into PGAL (3-phosphoglyceraldehyde).

But when there is a need for synthesizing fat in an organism. The Acetyl CoA is taken from the respiratory pathway. Respiration can cause both the breakdown as well as the synthesis of fatty acids, i.e., it is involved in both catabolism and anabolism. Therefore, it is to be an amphibolic pathway.