This pathway depicts the key steps in (very) long-chain fatty acid biosynthesis, belonging to the n-10, 9 and 7 series (counting first double bond from the methyl side).
These are mainly synthesised from palmitic acid (C16:0), which is produced by FAS (fatty acid synthase).
The n-6 and 3 series can only be obtained from precursors in food.
The elongation steps (addition of carbohydrates, increasing length of tail) are carried out by several Elovl-proteins.
The desaturation (removal of hydrogens, creating double bonds within the tail) are possible by SCDs and Fads (where is position of the double bound addition is indicated after delta, counting from the COOH side).