We have all been introduced to this topic atleast once before, even if it was not school related we all knew that when someone said lipids they were talking about something fat related. Some common structures of lipids would be :


Fats and oils. (triglycerides)

Fats are solids at room temperature, but oils are liquids

Fats contain SATURATED hydrocarbon  chains

Oils contain UNSATURATED hydrocarbon chains, this just means that they contain atleast 1 C-C double bond.


They are lipids and their molecules have single hydrocarbon chains that are linked to an alcohol

Really important in fruits for two reasons:

1. Protective layer in fruits, vegetables

2. Added in some cases for appearance and protection

Functions and Properties 

  • source of energy 
  • energy reserve, bascially if there is any excess energy from carbohydrates , proteins and lipids they are stored as TAG in adipose tissues
  • Provide insulation for the body
  • Protects vital organs
  • helps in the formation of cell membranes
  • steroid hormones
  • flavor and taste

Saturated Fats

All carbons are bonded to H

there is no C-C double bond

they form long straight chains

solid at room temperature

Mostly animal fats

Unsaturated fats

They contain C-C double bonds

Found in plant and fish fats

They are liquids at room temperature

Because of the presence of the double bonds they form kinks in the hydrocarbon chains, and this prevents the molecules from packing tightly together.


Effect of the double bond on Fatty acids

As the length of the fatty acid chain increases, the melting point of the fatty acid would increase but the solubility will decrease.

Stearic aicid and Linoleic acid both have the same number of carbon atoms but because of the presence of double bonds in Linoleic acid their melting points would vary.


Essential Fatty acids

They are the fatty acids that the body cannot produceor synthesize on its own, two examples are Omega – 3 alpha – linolenic acid and Omega – 6 Linoleic acid.

Omega 3 Fatty acid 

It is a cis isomer

Found in  flaxseed, soybean oil, walnuts, some leafy green vegetables.

Omega 6 Fatty acids

It is a cis isomer

Found in seed nuts, common vegetable oils , sunflower seed, cottonseed.

Nonessential fatty acids – can be made in the body so it is not required in the diet. 

References : Biochem Jm youtube channel , video on Lipids part one.


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