Chemical structure of a lipid



Lipids are macromolecules (polymer) made by fatty acids (monomer).



Carboxilic acid is the ¨head¨ and the fatty acid chain is the ¨tail¨


What Are Lipids? - Definition, Structure & Classification Of Lipids

As they are insoluble in water, they have a head and a tail, as seen in the picture.

There are 3 types of lipids:

  1. Triglycerides: are 3 chains of fatty acids bonded to one molecule of glycerol. There can be 3 types.


Saturated fats: single bonds, linear structure, solid. Example: Stearic acid.
Stearic Acid Jmol 

Monounsaturated fats: have 1 double bond, bent structure. Example: Oleic acid. 
Oleic acid | C18H34O2 - PubChem

Polyunsaturated fats: more than 1 double bond, bent structure.
Linoleic Acid: Imágenes, fotos de stock y vectores | Shutterstock

Triglycerides formation process is condensation to create a ester linkage, while the reverse process is hydrolysis.
Lipids Structure & Functions | A-Level Biology Revision Notes

     2. Phospholipids: derived from triglycerides, phospholipids are 2 chains of fatty acids bonded to         one glycerol molecule and one phosphate group.

Cape Biology and Chemistry Syllabus: Biology Module 1 - 1.aspects ...


As the phospholipid has a phosphate group, it is soluble in water because of the ion-dipole. 
Structural Biochemistry/Lipids/Micelles - Wikibooks, open books ...

Phospholipids heads are in contact with water (hydrophilic) while their tails get protected (hydrophobic). They arrange in a bilayer, as number 1 in the photo, and micelle, as number 2 in the photo. 

     3. Steroids: they arrange themselves to form hormones. Consist in 17 carbon atoms arranged in           rings. There are substituted functional groups to form different hormones.
Steroids



Bibliography: 

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