Cell Surface Membrane

Question 1

Explain fluid mosaic model

Answer 1

Fluid- phospholipids move around (by diffusion)
Mosaic- scattered pattern of proteins

Question 2

4 main componants of fluid mosaic model

Answer 2

Phospholipids
Glycoproteins + Glycolipids
Cholesterol
Transport Proteins

Question 3

Phospholipid structure

Answer 3

Hydrophilic phosphate heads
Hydrophobic fatty acid tails
Phosphate heads shield the fatty acid tails that face inwards

Question 4

Phospholipid Functions

Answer 4

Barrier to water soluble substances
Act as signalling molecules

Question 5

Cholesterol Functions

Answer 5

Controls the fluidity of the membrane (increases fluidity/rigidity depending on temp)
Increases mechanical strength

Question 6

2 transport protein types

Answer 6

Channel proteins
Carrier proteins

Question 7

Structure and role of transport proteins

Answer 7

Intrinsic proteins
Hydrophilic channels to allow polar molecules to pass

Question 8

Differences between carrier and channel proteins

Answer 8

carrier transport molecules, change shape
channel transport ions, fixed shape

Question 9

Glycolipid roles

Answer 9

Receptor molecules
Cell recognition
Antigens

Question 10

Glycoproteins role

Answer 10

Receptor molecules for cell signalling
Stabilise membrane (form hydrogen bonds)
Cell adhesion
Cell recognition

Question 11

How does cholesterol increase rigidity and fluidity
what does this prevent?

Answer 11

Increase rigidity= bind to hydrophobic tails to pack them closer together ( at high temp)
Increase fluidity= stops fatty acid tails binding too closely together (at low temp)

prevents cell bursting