Lipids are macromolecules that are insoluble in water.
They are present in living organisms and are also widely distributed in nature.
Examples of lipids include
|Sl.No||Type of lipid||Lipid name||Source|
|1||Oils||Peanut oil (arachis oil)||Peanut or ground nut|
|2||Sesame oil||Sesame seeds|
|5||clarified butter||Dairy products|
|6||Margarine||Vegetable oil + water|
|7||Hydrogenated vegetable fat||Vegetable oil|
|8||Eicosanoids||Prostaglandins||The cell membrane (arachidonic acid)|
|11||Steroid||Cholesterol||Synthesized in the body.|
Lipids are one of our body’s 4 significant macromolecules that are taken from an external diet.
Also, some of them are biosynthesized in our body as per need from excess carbohydrates and other sources.
Lipids vary in structure, properties, and functions in the body.
They are insoluble in water and hence called hydrophobic.
Types of Lipids
Lipids are of two types as
- Simple lipids
- Compound lipid.
These are the ones that are esters of fatty acid and alcohol. They are again of three types as
a) Neutral fats (glycerides)
- They have an ester of fatty acid and glycerol.
- They tend to accumulate in our bodies and contribute to weight gain.
- At room temperature, they are solid.
- Like fats, they are also esters of fatty acid and glycerol but are liquids at room temperature.
Ex: all edible oils
- These are also esters but have fatty acids linked with non-glycerol alcohol.
- This alcohol is a high molecular weight monohydric alcohol.
Ex: Bee wax.
- The fats are stored in the body and are used in times of starvation.
These are of different types based on the fatty acids in them. The fatty acids can be either saturated forms or unsaturated forms. The saturated fatty acids are
Fatty acid Structure
- Lipids are chemically the esters of long-chain fatty acids with alcohols.
- The elements carbon, hydrogen, and oxygen are structural components of fatty acids and have the following formula.
HOOC-(CH)2-CH3 fatty acids
- These have complex chemistry with cyclic structures or multiple functional groups.
- They are mostly involved in the formation of membranes of the body cells.
They are of different types like
- They have phosphate groups in their chemical structure.
- The phosphate moiety determines the water-permeable nature of the membrane it forms.
- These phospholipids are mostly present in cell membranes.
In general, a cell or plasma membrane has double layers of phospholipids, as shown in the image below.
- These lipids have amine and other functional groups in their chemistry.
- Sphingomyelin is a part of the nerve cell membrane.
- These lipids are formed inside the body and sometimes are taken from external sources.
- They have a cyclic ring-like structure in their chemistry, due to which they are called steroids.
- These steroids, like cholesterol, are chemical constituents of the cell membrane.
Frequently asked questions and answers
Which lipid acts as a chemical messenger
Lipids like prostaglandins, leukotrienes, and hormone-based lipids like testosterone, and estrogen act as chemical messengers.
Where is most of a healthy person’s fat stored?
Fat in a healthy person is stored below the skin and is mainly concentrated in the bums, soles, and palms.
What are the two main parts of a lipid molecule
Fatty acid and alcohol.
What are the building blocks of fats and oils?
Aliphatic Acids and alcohols act as building blocks of fats and oils.