Boundaries and Membranes

Question 1

What do cell boundaries allow?

Answer 1

1) Formation of a semi-fluid matrix for cell function
2) Formation of specialised microenvironments where concentrated solutes can form for cell processes
3) Segregation of harmful activites

Question 2

What is the principle boundary?

Answer 2

The exterior plasma membrane

Question 3

What is the most common phospholipid in eukaryotic cell membranes?

Answer 3

Phosphatidyl Choline

Question 4

What is the purpose of cholesterol in membranes?

Answer 4

Stiffens the membrane. In fungi, Cholesterol is replaced with Ergosterol

Question 5

Name 4 key structural features of lipid membranes?

Answer 5

1) Lipid bilayers are self-assembling (repair tears)
2) Lipid layers are fluid but proteins are more restricted with movement
3) The bilayer is asymmetric
4) Integral proteins pass through the lipid bilayer

Question 6

What is the main component of cell walls in Bacteria, Fungi and Plants?

Answer 6

Bacteria - Peptidoglycan
Fungi - Chitin
Plants - Cellulose