Phospholipid Structure

Cell Membrane CH

Phospholipid

A molecule with a polar phosphate head group and two fatty acid chains, connected by a glycerol backbone.

Fatty Acid

A carboxylic acid attached to a long carbon chain (R-group), consisting of a double-bonded oxygen and a hydroxyl group (COOH).

Glycerol Backbone

Each phospholipid has only one glycerol molecule. A simple molecule consisting of three carbon atoms, each attached to a hydroxyl group (OH).

Phosphate Group

The polar head of the phospholipid, consisting of a phosphorus atom with four oxygens attached.

Ester Bonds

Helps attach the two fatty acids to the glycerol backbone in a phospholipid molecule. Another Ester Bond attaches the glycerol to the phosphate group. One of the oxygens in the phosphate group is replaced by a hydroxyl group (OH) in the cell.

Phosphoester Bond

The bond formed between a hydroxyl group (OH) and the phosphate group in phospholipids.

Common Phospholipids

Examples include Phosphatidylserine, Phosphatidylcholine, Phosphatidylethanolamine, Phosphatidylinositol, and Diphosphatidylglycerol.

Polar head and Nonpolar head.

• The polar head group faces the outside.

• The nonpolar fatty acid chains face the inside.

• The glycerol group holds everything together.

Carbon Chains in Fatty Acids.

Can form double bonds that are either Cis or Trans.

Cis Bond

A type of double bond where the carbons on either side are on the same side, creating a kink in the fatty acid chain.

Trans Bond

A type of double bond where the carbons are on opposite sides, keeping the fatty acid chain straight.

Fluidity of Cell Membrane

The presence of cis and trans bonds in fatty acids affects the fluidity of the cell membrane.