Cell Membrane Structure

Question 1

What is the basic structure of a cell membrane?

Answer 1

Phospholipid bilayer

[Two layers of phospholipids]

Question 2

What is the structure of a phospholipid?

Answer 2

Phospholipid- polar, hydrophilic head, -ve
2 fatty acids- non polar, hydrophobic
2 hydrophobic tails

Question 3

How do phospholipids arrange themselves in water?

Answer 3

May form:
Monolayer on the surface- hydrophobic tails out of water.
Spherical michelle
Bilayer

Question 4

What is the preferred arrangement of phospholipids in water? Why?

Answer 4

Most stable arrangement is a bilayer
Fatty acids are too bulky to fit into the interior of the michelle.
Bilayer arrangement ensures the hydrophilic phosphate heads are in contact with the water whilst avoids hydrophobic fatty acids from contacting water
Bilayer closes on itself so there are no edges with exposed hydrocarbons.

Question 5

What are cells filled and surrounded by?

Answer 5

Cells are filled with an aqueous cytoplasm and are surrounded by aqueous tissue fluid.