In this A-Level Biology Lesson “Lipids: The Properties of Phospholipids” following an outline of the learning outcomes we’ll learn all about Phospholipids (The 2nd Lipid you need to know all about!). Phospholipids are similar to triglycerides (having a glycerol with fatty acids attached - but here we’ll look at the The Structure of a Phospholipid - a structure you should be able to recognise and label up under exam conditions.

You’ll learn that Phospholipids are Ambivalent Molecules and that Phospholipids form monolayers (called micelles). Finally we’ll see that Phospholipids are super important biomolecules in living organisms as Phospholipids form bilayers, that is to say in living organisms Phospholipids form Cell Membranes!

When you’ve finished learning all about Phospholipid structure and function you'll be ready to download the knowledge check PDF - quickly re-cap the notes and test your knowledge with the knowledge check questions. When you have you answered them make sure you check your answers with mine which are written out in full in the back of the work book (no rubbish one word mark schemes here!). So, you can see exactly how you should write your answers in a way that gains maximum marks in the exams.

A-Level Biology "Lipids: The Properties of Phospholipids"

Phospholipids are similar to triglycerides, but rather than having 3 fatty acids attached to glycerol, Phospholipids have 2 fatty acids and a phosphate group.

Phospholipids are fundamental molecules in all living organisms!

Phospholipids are composed of the hydrophilic (water loving) phosphate head and the hydrophobic (water hating) fatty acid tails.

Phospholipids are ambivalent (i.e. a molecule that has different properties when placed in water). Because of this, when placed in water phospholipids spontaneously form monolayers known as micelles.

As you will see, micelles orientate themselves so that the hydrophilic phosphate head of the phospholipid is “facing outwards” dissolved in the water and protecting the hydrophobic fatty acid tails which are orientated “inwards”.

In living organisms, Phospholipids form Bilayers!

The Phospholipid bilayer is the fundamental structure of all cell membranes. 

The Phospholipid bilayer separates the internal cellular environment from the external cellular environment.

Phospholipids are ambivalent (i.e. a molecule that has different properties when placed in water). Because of this, when placed in water phospholipids spontaneously form monolayers known as micelles.

As you will see, micelles orientate themselves so that the hydrophilic phosphate head of the phospholipid is “facing outwards” dissolved in the water and protecting the hydrophobic fatty acid tails which are orientated “inwards”.

In living organisms, Phospholipids form Bilayers!

The Phospholipid bilayer is the fundamental structure of all cell membranes. 

The Phospholipid bilayer separates the internal cellular environment from the external cellular environment.