Question

what is the difference between a triglyceride and a lipid? why are they not equivalent terms?

Answer 1

Lipids
• Lipidsarebiologicalmoleculesthatareinsolublein water but soluble in nonpolar solvents.
– Lipids have a wider spectrum of compositions and structures because they are defined in terms of their physical properties (water solubility).
• Lipids are the waxy, greasy, or oily compounds found in plants and animals.
– wax coating that protects plants
– used as energy storage
– structural components (cell membranes)
– insulation against old

Classification of Lipids
• Lipidsaredividedinto:
– Saponifiable lipids — contain esters, which can undergo saponification (hydrolysis under basic conditions) (waxes, triglycerides, phospho- glycerides, sphingolipids)
– Nonsaponifiable lipids — do not contain ester groups, and cannot be saponified (steroids, prostaglandins)
• Saponifiablelipidscanalsobedividedintogroups:
– Simple lipids — contain two types of components (a fatty acid and an alcohol)
– Complex lipids — contain more than two components (fatty acids, an alcohol, and other components)

Triglycerides
• Animalfatsandvegetableoilsareesterscomposed of three molecules of a fatty acid connected to a glycerol molecule, producing a structure called a triglyceride or a triacylglycerol.

So,Lipids are a broad group of macronutrients which plays a major role as a structural molecule and an energy source. Triglycerides, phospholipids, and steroids are different types of lipids found in the body. The two types of triglycerides are fats and oils. The main difference between lipids and fats is that lipids are a broad group of biomolecules whereas fats are a type of lipids. Fat is stored in the adipose tissue and under the skin of animals. It is mainly used as an energy-storage molecule in the body. Most steroids in the body serve as hormones. Phospholipids mainly occur in the cell membrane.