Which of these is NOT a lipid?
The correct option is A.
Why option B is incorrect:
Phospholipids are a group of lipids that are components of cell membranes. It consists of a tail that is composed of two hydrophobic fatty acids and ahead of a phosphate group. Therefore, this option is incorrect.
Why option C is incorrect:
Steroids are also a class of lipids because they consist of hydrophobic. They are insoluble in water. Yet they have a different structure than lipids composed of four rings. So, this option is also incorrect.
Why option D is incorrect:
Cholesterol is a steroid; therefore, it is a lipid. Basically, it is partially lipid and partially proteins. They are also called lipoproteins. Hence, this option is also wrong.
Why option E is incorrect:
Waxes are also simple lipids. They are found in nature on stem and leaves as a coating.
RNA is not a lipid; therefore, the correct option is RNA. Let’s first understand what lipids are.
Lipids are the building blocks of all living organisms. These are molecules that are made up of hydrocarbons. Waxes, fats, oil, and vitamins are lipids.
Lipids are non-polar, therefore insoluble in water but are soluble in non-polar solvents such as chloroform.
Lipids mainly consist of hydrocarbons, making them the best form of energy storage, as when metabolized, the hydrocarbons oxidize to release large amounts of energy.
RNA is also called ribonucleic acid. It is a polymeric molecule that is essential in various biological roles such as coding, decoding, regulation, and expression of genes.
RNA is a nucleic acid that constitutes macromolecules in a body along with lipids, proteins, and carbohydrates.
RNA is made up of one or more nucleotides. Each nucleotide consists of a base, a ribose sugar, and a phosphate group.