The human body is composed of trillions of cells. It is important that anatomy and physiology students have a sound understanding of cellular anatomy.

Lipids

A lipid hydrophobic organic molecule

Hydrophobic molecules are non-polar and therefore do not mix with water.

Organic molecules are molecules that are made of carbon and hydrogen, and can include other elements.

Organic molecules must contain carbon atoms covalently bonded to hydrogen atoms (C-H bonds).

Lipids are composed of only carbon, oxygen and hydrogen

Lipids typically have a high ratio of hydrogen to oxygen

Lipids are also known as fats

The primary function of lipids is energy storage

Also serves as a thermal insulator and shock absorber

The four classes of organic molecules in the human body are carbohydrates, lipids, proteins, and nucleic acids.

Phosphate Head

A Functional Group

Functional groups are small clusters of atoms bound to the carbon backbone of atoms of organic molecules.

Functional groups help determine the properties of the molecule.

Phosphate groups are one of the functional units and contain central phosphate atom(s)

The phosphate head of a phospholipid is hydrophilic meaning it mixes well water.