(L5) triglycerides continued - phospholipids

Components of a phospholipid

A glycerol backbone, $2$ fatty acids, and $1$ phosphate group (charged phosphorus and oxygen).

Formation of a phospholipid

• Formed via condensation reactions that release water
• Creates ester bonds
• Composed of $1$ glycerol, $2$ fatty acids, and $1$ phosphate-containing group
• Replaces $1$ fatty acid compared to a triglyceride

Define Amphipathic

• Having both hydrophobic and hydrophilic properties

What are the amphipathic properties of phospholipids?

• phosphate head = hydrophilic (polar)

• fatty acid tails = hydrophobic (non-polar)

What is the structure of cholesterol?

Structure of Cholesterol

• Part of plasma membrane.

• Maintains fluidity of Cell.

• Steroid alcohol (HO⁻ group). → polar molecule.

• Synthesised in the liver.

• Hydrophobic, Small and polar.

• 1/ Carbon Ring inside.

Define hydrophobic

Repels water

Define hydrophilic

Attracted to water

What are the properties, behaviours and functions of the phosphate containing group in a phospholipid?

-polar and hydrophilic

-interacts with water and faces towards it

-this acts as a selective barrier for the cell

What are the properties, behaviours and functions of the Two fatty acid chains in a phospholipid?

-non polar and hydrophobic

-moves away from water and faces away from it

-forms a part of the cell membrane surface and acts as a selective barrier

What are the properties, behaviours and functions of the Whole phospholipid?

-Amphipathic

-forms a bilayer

-maintains cell fluidity and the basic structure of the cell membrane