Practicing Success

Target Exam

CUET

Subject

Biology

Chapter

Biomolecules

Question:

Triglyceride consist of :

Options:

Three fatty acids + one glycerol.

Three fatty acids + two glycerol.

One fatty acids + one glycerol.

One fatty acids + three glycerol.

Correct Answer:

Three fatty acids + one glycerol.

Explanation:

The correct answer is Option (1) –Three fatty acids + one glycerol.

Lipids are generally water insoluble. They could be simple fatty acids. A fatty acid has a carboxyl group attached to an R group. The R group could be a methyl (–CH3 ), or ethyl (–C2H5 ) or higher number of –CH2 groups (1 carbon to 19 carbons).

For example, palmitic acid has 16 carbons including carboxyl carbon. Arachidonic acid has 20 carbon atoms including the carboxyl carbon.

Fatty acids could be saturated (without double bond) or unsaturated (with one or more C=C double bonds).

Another simple lipid is glycerol which is trihydroxy propane. Many lipids have both glycerol and fatty acids. Here the fatty acids are found esterified with glycerol. They can be then monoglycerides, diglycerides and triglycerides. These are also called fats and oils based on melting point. Oils have lower melting point (e.g., gingelly oil) and hence remain as oil in winters.

Fat is stored reserve for the body which provides energy. These are triesters of glycerol. It is obtained from fatty acids and glycerol. It consists of one glycerol molecule and three fatty acid molecules. The carboxyl end of the fatty acid combines with the three -OH groups of the glycerol to form the ester.