Question

How does the structure of lipids relate to its function?

Answer 1

Hint: The organic compounds that are insoluble in polar solvents and are composed of fatty acid chains belong to the group lipids. They are mainly composed of fats and oils.

Complete answer:
1)The lipids are the organic compounds soluble in nonpolar or organic solvents and generally comprises the fatty acids or their derivatives. These hydrocarbons form the basic framework for the structure and function of living cells. They are naturally occurring and are heterogeneous in nature. Their major types are- wax, oils, fats, hormones- steroids, and phospholipids.

2)They are generally long chains of fatty acids. They have long chains of non-polar hydrocarbons and a polar molecule like glycerol. The length, number, and nature of these chains can differ. The structure of these lipids also defines the function they perform.

3)They form an integral framework of the cell membrane. Phospholipids are a major class involved. They have a phosphoric acid along with fatty acids and alcohol. They form a lipid bilayer structure that provides the structural framework of the membrane. It also acts as a barrier between the organelles and prevents the diffusion of the substances. It also provides selective permeability to a few substances. Lipid bilayer structures have their polar head facing outwards and their non-polar tails facing inwards.

4)Fats are simple lipids that contain a glycerol molecule along with three fatty acids and are thus called triglycerides. They are referred to as esters of fatty acids. They are required for the proper functioning of the body. They also store energy in the form of triglycerides. Their structure also provides insulation to our body and maintain our body temperature. The absorption of many fat-soluble vitamins is also facilitated by them.

5)Oils are fats in liquid states that provide energy and fulfill the calorie requirement.
Waxes have long fatty acid chains and alcohols linked with ester linkages. The hydrophobic non-polar chains of the carboxylic acids provide a waxy coating that prevents the loss of water. These wax coatings are present on plants, some insects, and some bird’s feathers.

6)They also store energy in their structures in various aquatic organisms.
Steroids have four carbon rings linked to each other and a tail and alcohol attached to them. Their structure is different from the other lipid molecules. The most common steroid molecule is cholesterol which forms an integral part of the cell membrane. It is also a precursor to Vitamin D and many other hormones. Steroids can also act as signalling molecules, hormones, and messengers. They also help in metabolism and immune functions.
Glycolipids consist of fatty acids linked with a carbohydrate molecule and a glycerol group. They provide cellular recognition and structure to the cell membrane.
The fatty acid chain can be unsaturated or saturated in lipids. The saturated chains have high melting points.

Note: Lipids are synthesized in the endoplasmic reticulum and sometimes the Golgi apparatus of the cells. In animals, the lipid synthesis can occur in the liver or can be obtained from food. The synthesis and degradation of lipids in the cells are called lipid metabolism.