Question

Which of these is not a lipid
A: Steroid
B: Fat
C: Polysaccharide
D: Wax

Answer 1

Hint: Lipids are biomolecules that can be dissolved in nonpolar solvents. On-polar solvents are usually hydrocarbons used to dissolve other naturally occurring hydrocarbon lipid molecules that do not dissolve (or do not dissolve easily) in water. Lipids are a class of organic compounds that include fats and oils.

Complete explanation:
Option A: Steroids are lipids because they are hydrophobic and insoluble in water, but they are not lipids because their structure is made up of four fused rings. The most popular steroid is cholesterol, which is the precursor to vitamin D, progesterone, testosterone, oestrogen, aldosterone, cortisol, and bile salts.
So, option A is incorrect.
Option B: Fat is typically described as any ester of fatty acids or a mixture of such compounds, most commonly those found in living beings or food. The term is also used to refer to triglycerides (triple esters of glycerol), which are the primary components of vegetable oils and fatty tissue in animals.
So, option B is incorrect.
Option C: Polysaccharides are the most common form of carbohydrate contained in food. They are polymeric long-chain carbohydrates made up of monosaccharide units linked together by glycosidic linkages. They have a variety of structures ranging from linear to strongly branched. Starch, glycogen, cellulose, and chitin are a few examples.
So, option C is correct.
Option D: Waxes are fatty acid esters of long chain monohydric alcohols (one hydroxyl group). Waxes are soluble in organic, nonpolar solvents but insoluble in water. Unsaturated bonds can be present in natural waxes, as well as functional groups such as fatty acids, primary and secondary alcohols, ketones, aldehydes, and fatty acid esters.
So, option D is incorrect.

So, option C is the correct answer to this question.

Note:
Lipids are hydrocarbon-containing molecules that serve as the foundation for the structure and function of living cells. Lipids are fatty acid polymers with a long, non-polar hydrocarbon chain and a small polar area containing oxygen. Lipids include fats, oils, waxes, vitamins (such as A, D, E, and K), and hormones. Lipids perform a variety of roles, including energy storage, signalling, and functioning as structural components of cell membranes. Lipids find use in the cosmetic and food industries, as well as in nanotechnology.