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Introduction to the lesson
In the previous lesson, we looked at the structure of phospholipids and how their properties make them ideal as the building blocks of cell membranes. However, phospholipids are not the only molecules found in cell membranes. In this lesson we will look at other molecules which make up the cell membrane and the function that they play.
Structure of the membrane
Read the section “Structure of membranes” in your text book (p.74-77)
Learning Activity 1
Answer the following questions in your exercise book.
- Copy Fig. 4.5 (p.75 of your textbook) for yourself and label the following
- Outer and inner surface
- Phospholipid bilayer
- Hydrophobic tails
- Hydrophillic heads
- Cholersterol
- Glycoprotein
- Glycolipid
- Transport protein
- Protein
Features of the fluid mosaic model
Learning Activity 2
Answer the following questions in your exercise book.
- List the features of the fluid mosaic model in simple terms.
- What in the phospholipid molecules makes the membrane more fluid?
- What is cholesterol and what properties of cholesterol make it effective in its role?
- What two conditions can make the membrane less fluid?
Roles of the components of cell membranes
Learning Activity 3
Answer the following questions in your exercise book.
- Explain the roles of the following components of cell membranes:
- Phospholipids
- Cholesterol
- Glycolipids
- Glycoproteins
- Membrane proteins
Definitions and review
Definitions
- Fluid mosaic model
- Intrinsic proteins (integral proteins)
- Transmembrane proteins
- Extrinsic proteins (peripheral proteins)
- Cholersterol
- Glycolipids
- Glycoproteins
- Glycocalyx
- Receptor molecules
- Antigens
- Channel proteins
- Carrier proteins
Mindmap
Add this section to your chapter four mindmap.