Membrane structure 1.3

The first models of membranes included protein and phospholipids but not in the same structure as we see them today. In this topic the components of cell membranes are investigated and the structure of the membranes as fluid and dynamic structures is outlined.

Key concepts

Learn and test your biological vocabulary for Membrane structure 1.3 using these flash cards 


These slides summarise the essential understanding and skills in this topic. 
They contain short explanations in text and images - good revision for all students.

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Stretch for 7

These slides cover difficult parts of this topic - important if you are aiming for a high grade.
If grade 5 is your target, then save time, move on, study this information later, once you have revised the other topics.




Summary list for topic 1.3 Membrane structure

  • Phospholipids form bilayers in water due to the amphipathic properties of phospholipid molecules.
  • Membrane proteins are diverse in terms of structure, position in the membrane and function.
  • Cholesterol is a component of animal cell membranes.
  • Application: Cholesterol in mammalian membranes reduces membrane fluidity and permeability to some solutes.
  • Can you draw a diagram of the fluid mosaic model.
  • Can you explain how evidence from electron microscopy led to the proposal of the Davson-Danielli model.
  • Can you outline the evidence which led to the falsification of the Davson-Danielli model and support of the Singer-Nicolson model.


This diagram summaries the main sections of topic 1.3 about membrane structure.
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Exam style questions

Skills video tutorial

Explaining plasma membrane structure and the structure and function of the molecules in the membrane is an important skill in this topic. This video tutorial explains how to draw a simple 2D diagram of a cell membrane, and label it for an IB Biology exam.

How to draw a membrane diagram in an exam from David Faure on Vimeo.


Extra exam question

More questions coming soon.

Test yourself

This quiz contains a set of multiple choice questions covering the membrane structure topic. Explanations of each answer are displayed after you click to check the answer(s).


Just for fun

If you want to review key terminology and have some fun with your revision try this. It will help you remember the terms through repetition. Membrane structure card match game.

Alternatively this choice of Arcade games will help you to practise the basics while having fun. Arcade game "Membrane structure".