Cell membranes and transport
All living cells are surrounded by a very thin membrane.
This controls the exchange of materials such as nutrients and waste
products between the cell and it’s environment. Another important
function of membranes is that they enable cells to receive hormone
messages.
Phospholipids
To understand the structure of the membranes you must understand the
structure of phospholipids, little bags can be formed inside which
chemicals can be isolated from the external environment. These bags are
membrane bound compartments we know as cells and organelles.
Figure 1 Phospholipids in water
A single layer with their heads in the water and tails projecting out of the
water is formed, can you explain why this happens?
Cell membranes and transport
Figure 2 Phospholipids forming a ______________.
If phospholipids are shaken up with water, they form stable ball-like
structures in the water called _________________.
What happened in this diagram?
Cell membranes and transport
Figure 3 Phospholipids form bilayers
Explain what happens in this diagram?
Structure of membranes
What magnification on the electron microscope is needed to see the
phospholipid bilayer?