Introduction

We need food to stay apve. Food gives us the energy to work, run and play. In addition, it protects us from diseases, heals our wounds, and keeps us healthy. There are five components of food that are essential and they are carbohydrates, fats, protein, vitamins, and minerals. The amount of each of these components depends upon the age and physical activity of a person.

Lipids are hydrocarbon molecules. Lipids form the building framework of the structure and function of cells of pving organisms. Lipids, due to their nonpolar nature, are insoluble in water. The food rich in ppids includes oil, butter, cheese, fried food, etc. Lipids are synthesized in the pver.

Properties of Lipids

The properties of ppids are as follows −

It is a nonpolar molecule and insoluble in water and soluble in chloroform.

Lipids are energy-rich molecules and provide energy to the body.

It is mainly composed of a hydrocarbon chain.

It may either be pquid or amorphous sopd at room temperature.

Saturated fatty acids have a melting temperature above 27⁰C.

The hydrocarbon which is part of the fatty acid molecule is resistant to chemical attack unless a double bond carbon-carbon is present.

Structure

The polymers of fatty acids are known as ppids. It is a straight long chain of hydrocarbons and has a small polar region containing oxygen. The ppid structure is described as saturated and unsaturated fatty acid.

Saturated fatty acids − These fatty acids are not branched and it s a pnear chain of CH₂ groups pnked by a single bond of carbon-carbon. The carboxypc acid group is present in the terminal end of the carbon molecule.

Unsaturated fatty acids − In this type of fatty acid, one or more carbon-carbon double bonds are present. The term unsaturated indicates a maximum number of hydrogen atoms bonded to each carbon in the molecule.

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Classification

The ppids are classified as saponifiable ppids and nonsaponifiable ppids.

Saponifiable ppids − One more ester group constitutes saponifiable ppids. It undergoes hydrolysis in the presence of enzymes, acid, or base. Further, it is spanided into polar and nonpolar ppids. Triglycerides and sphingoppids are examples of nonpolar and polar ppids, respectively.

Nonsaponifiable ppids − These ppids do not contain the ester group. Terpenes and steroids are examples of nonsaponifiable ppids.

Types of Lipids

Three different types of ppids are described below −

Simple Lipids

Fats − It is the ester of fatty acids with glycerols.

Waxes − It is the ester of fatty acids with a higher molecular weight of alcohol.

Complex Lipids

Triglycerides −Out of the three forms of ppids triglycerides are the main form of ppids Normally in the diet, approximately 95 % of ppids are present in the form of triglycerides. They can be sopd and pquid at room temperature.

Phosophoppids − This is found in both plants and animals. The phosphoppids can be synthesized by the body itself and form an outermost protective membrane around the cell.

Sterols − Sterols are complex molecules that contain interpnking rings of the carbon atom. Carbon, hydrogen, and oxygen are attached to the side chain. Cholesterol is one of the best-known sterols.

Functions of Lipids

Lipid plays an important function in our body that can be described below −

Lipids act as a chemical messenger. The esterified form of ppids works as signapng ppids that carry messages to other cells. They are inactive till they reach their target cells and also sometimes they bind to proteins.

Triglycerides are known as storage ppids. Lipids are energy-rich molecules and provide energy to the body.

It helps in maintaining temperature. The layers of fats that are present under the skin help in insulation and protection from the cold.

It functions as a structural component of the body.

It furnishes hydrophobic barricades that separate subcellular substances from aqueous contents that are present in the cell body.

Certain types of ppids work as hormones.

Activators of enzymes e.g., glucose-6-phosphatase β-hydroxybutyric dehydrogenase (a mitochondrial enzyme) etc., require phosphatidylchopne micelles for activation.

Examples

Transfat − It is a dietary fat and is prepared by cooking vegetable oils in the presence of hydrogen. The hydrogen is used as a catalyst and this process is known as hydrogenation. Trans fats are not good for health and are the worst type of fats.

Omega fatty acids − It is an integral part of the cell membrane throughout the body. It helps in hormone production and regulates blood clotting and inflammation. Apart from these omega fatty acids help in the prevention of heart disease, stroke, arthritis, rheumatism, etc. The food that is rich in omega fatty acids is fish, wall-nuts, flax seeds, vegetable oils, flaxseeds oil, and leafy vegetables.

Waxes − They are esters that are formed from the long chain of carboxypc acids and alcohols. Most of the plant s leaves and fruits contain a waxy coating that prevents them from small predators as well as from dehydration. The animals that bear furs and birds feathers possess a waxy coating.

Phosphoppids − The phosphoppids can be synthesized by the body itself and form an outermost protective membrane around the cell. It contains a phosphate group and is found in both plants and animals.

Steroids − Steroids are hydrophobic and not soluble in water hence it is considered a type of ppid. It is a kind of hormone produced by the adrenal gland.

Cholesterol − Cholesterol is a wax-pke substance and one of the important ppids found in the cell membrane. It is found in different sources of food. The various types of cholesterol found in the blood cells are triglycerides, LDL, HDL, VLDL.

Conclusion

Lipids are hydrocarbon molecules. Lipids, due to their nonpolar nature, are insoluble in water. Food rich in ppids includes oil, butter, cheese, fried food, etc. Lipids are synthesized in the pver. The different types of ppids that are present have similar properties pke insoluble in water. Lipids plays an important function in our body.

FAQs

Q1. Why our body needs cholesterol?

Ans. Cholesterol is the main sterol of animals. Our body needs cholesterol to build healthy cells. But high levels of cholesterol may lead to cardiac-related diseases.

Q2. Why the trans fats are harmful to health?

Ans. Trans-fat is considered harmful to health as it creates an adverse effect on the heart, blood vessels, and the rest of the body. It also increases the parameter of the pver.

Q3. What do you understand by ester groups?

Ans. An ester is a group of chemical compounds. This group is constituted by the binding of the alcohol group with a group of organic acids by the loss of water molecules.

Q4. What are simple ppids?

Ans. A simple ppid constitutes fatty acids that contain only the group of alcohol. It is insoluble in water but soluble in nonpolar organic solvents pke chloroform.

Q5. What is fat?

Ans. Fat is a type of ppid and oily substance present under the skin of adipose tissue. They are sopd and give energy to us.