Exam questions 2.5 Cell membrane

Question 1

State the functions of cholesterol

Answer 1

Control fluidity/stabilise membrane
Reduces permeability for polar particles

Question 2

state the function of a phospholipid bilayer

Answer 2

act as a barrier/ select what enters and leaves the cell

Question 3

What is meant by ‘cell signalling’

Answer 3

Communication between cells
Cell recognition
Cells work together to trigger response

Question 4

What is the approximate width of the cell surface membrane

Answer 4

7 nanometres (nm)

Question 5

what is a channel proteins function

Answer 5

allows charged molecules through the membrane

Question 6

roles of glycoproteins in membranes

Answer 6

-binding sites for chemicals
-antigens for cell recognition
-stabilises membrane structure by forming hydrogen bonds with water (cell adhesion)
-receptors for cell signalling

Question 7

outline the roles of membranes at the surface of cells

Answer 7

-receptors for hormones ect.
-barrier to control substances entering/exiting
-cell surface antigens
-cell attachment
-separate cell from environment

Question 8

outline the role of membranes within the cell

Answer 8

-site of chemical reactions
-compartmentalises organelles
-ribosomes/enzymes attach