Lipids

By Sol Hong

Monomers

  • Glycerol- sweet-tasting molecule added in food.

  • Fatty acids- made of carboxyl group with carbons attached.

Polymers

  • Triglycerides- Made from three molecules of fatty acids and one glycerol molecule, the fat can be either unsaturated or saturated. These are crucial in the body for energy storage.

  • Steroids- Has a structure that has four rings fused together which are made from carbon molecules. These benefit the body by helping to determine and control the structure of plasma membrane.

  • Phospholipids- Their composition is primarily phosphate groups. They contain molecules that both attract and repel water, playing the main role in forming cell membranes.

  • Glycolipids- They are made up of short sugar chains, which can be found in a cellular membrane surface. They are important in improving the body’s immune system.

  • Lipoproteins- A combination of proteins and lipids found in a cell’s membrane. They help fat move around the body in the bloodstream.

  • Waxes- A chain of alcohols and fatty acids. This lipid is very common and it is found on animal feathers, in human ears, and also on the leaves of plants. Its function is to protect the insides from the exterior world.

Examples

  • Fats - saturated fat, unsaturated fat, monounsaturated fat, trans fat, and polyunsaturated fat

  • Steroids - cholesterol, estrogen, testosterone, bile salts, and cortisol.

  • Waxes - bee wax, ear wax, cutin (wax from plants)

  • Vitamins - A, D, E, K

Functional Groups

  • OH- Hydroxide

  • CH2- Methylene

  • COOH- Carboxylic acid

  • PO4- Phosphate

Common Function

Lipids help store energy, cushion and protect the organs, and insulate the body and form cell membranes.

Structure

Depending on its structure, the function of the lipid changes. For example, wax is a chain of alcohols and fatty acids. This lipid is very common and it is found on animal feathers, in human ears, and also on the leaves of plants. Its function is to protect the insides from the exterior world.