Phospholipids

Phospholipids are polar molecules

Having a hydrophilic phosphate head and a hydrophobic tail of two fatty acids

This means that in an aqueuos environment phospholipid molecules form a bilayer within cell surface membranes

As a result barrier is formed between the inside and outside of the cell 

Made of a glycerol molecule, two fatty acid chains and a phosphate group ( attached to the glycerol)

Two fatty acids also bond to the glycerol via two condensation reactions, resulting in two ester bonds

Hydrophilic phosphate heads of a phospholipid molecule

Can help molecules to hold at the surface of the cell surface membrane

Phospholipid structure

Allows them to form glycolipids by combining with carbohydrates within the cell surface membrane

Properties

Hydrophillic head of a phospholipid can interact with the water as it is charged

Due to the phosphate being charged (polar) it repels other fats

The fatty acid chain is not charged (non-polar) - it is known as the hydrophobic tail and it repels water but will interact with fats

Glycolipids are 

Important to cell recognition 

In an aqeous environment

Phospholipids arrange themselves into a bilayer where: the hydrophillic heads face outwards toward the water (both inside and outside the cell)

The hydrophobic tails face inward, away from the water forming a protective layer

This structure forms the phospholipid bilayer which is the basic structure of the plasma membrane surrounding all cells