Overview of Metabolism and Pathways

Study Notes

The sum of all chemical processes occurring within a living organism to maintain life is known as metabolism.
Primary metabolism, which includes processes like photosynthesis and respiration, is directly involved in growth and development.
Secondary metabolism encompasses reactions that produce organic compounds not directly involved in growth, such as alkaloids and terpenoids.

This pathway utilizes erythrose 4-phosphate and phosphoenolpyruvate as precursors to synthesize aromatic amino acids such as L-tryptophan, L-tyrosine, and L-phenylalanine.
The pathway involves several steps, including the formation of 3-Deoxy-D-arabino-heptulosonate-7-phosphate, 3-Dehydroquianate, 3-Dehydro shikimate, Shikimate, Shikimate 3-phosphate, 5-Enolpyruvylshikimate 3-phosphate, and finally, Chorismate.

This pathway uses Acetyl-CoA and Malonyl-CoA to synthesize fatty acids.
The pathway involves multiple steps, including the formation of Acetoacetyl-CoA, Palmitoyl-ACP, and ultimately, Palmitic acid.
Fatty acid elongation continues through repeated rounds of the cycle.

Acetyl-CoA serves as the precursor in this pathway, leading to the production of Isopentenyl pyrophosphate (IPP) and various terpenoids, including steroids.
The synthesis of IPP involves several steps, including the formation of β-Hydroxy-β-methylglutaryl-CoA, Mevalonic acid, and finally, Isopentenyl pyrophosphate.
IPP is used to synthesize different terpenoids based on the number of isoprene units:
- Hemiterpenoids: C5
- Monoterpenoids: C10
- Sesquiterpenoids: C15
- Diterpenoids: C20
- Triterpenoids: C30
- Tetraterpenoids: C40

This pathway utilizes Acetyl-CoA to synthesize cholesterol, steroid hormones, Vitamin D, and bile acids.
The pathway involves multiple steps, including the formation of β-Hydroxy-β-methylglutaryl-CoA, Mevalonic acid, and Isopentenyl pyrophosphate.
IPP is further used to synthesize Farnesyl pyrophosphate, which is then converted to Squalene.