Question

What are glycerides of fatty acids?
(a) Lecithin
(b) Phospholipids of plasma membrane
(c) Vegetable oils
(d) All of the above

Answer 1

Hint: Fatty acids are the building blocks of the fat in our body. Fatty acid molecules are usually present in groups of three, forming molecules called triglycerides. Molecules that have fatty acids or their derivatives in their structure are termed as glycerides of fatty acids.

Complete answer:
Glycerides are esters of glycerol and fatty acids that are hydrophobic. Glycerol has three hydroxyl functional groups which can be esterified with fatty acids to form mono-, di- or triglycerides.
Vegetable oils and animal fats are mostly triglycerides. They are broken down by enzymes like lipases into mono and diglycerides and free fatty acids and glycerol.
Phospholipids of the plasma membrane consist of a glycerol molecule, two fatty acids, and a phosphate group that is modified by an alcohol. Uncharged fatty acid chains help in formation of the hydrophobic, non- polar tails of the phospholipids.
Lecithin is a term designated to the groups of fatty substances seen in animal and plant tissues that are amphiphilic, i.e., attract both water and fat- soluble substances. They are mixtures of glycerophospholipids including phosphatidylcholine, phosphatidylinositol, and phosphatidic acid. It is composed of phospholipids, it too is composed of glycerides and fatty acids.
So, the answer is, “ All of these.”

Note:
- Partial glycerides are different from glycerides. Partial glycerides are glycerol with fatty acid but hydroxyl groups here are not esterified.
- Lecithin is important for the body as it acts as a precursor for the synthesis of choline and acetylcholine which is a neurotransmitter.
- Deficiency of lecithin can cause neurological disorders like bipolar disorder and also hampers the membrane phospholipid metabolism.
- Glycerol is not a component of phospholipids. It contains only phosphate and fatty acids.