Cell Membrane -W1

Question 1

Main roles of cell Membrane (3)

Answer 1

Transport
Organisation
Protection

Question 2

Amphiphilic define

Answer 2

Both hydrophilic and hydrophobic

Question 3

Phospholipids have a ……./…..head and a ……../…..tail

Answer 3

Hydrophilic/polar
Hydrophobic/nonpolar
Therefore can self arrange

Question 4

Cholesterol interacts with ……. in cell membrane

Answer 4

Fatty acid chains

Question 5

Role of cholesterol in membrane (2main and explanations)

Answer 5

Strengthens bilayer - less permeable to water soluble molecules

Maintains membrane fluidity(buffers effect of temperature)
Prevents lower temp from –> solid
Prevents high temp from –> increasing fluidity

Question 6

2 types of membrane proteins

Answer 6

Peripheral - span membrane

Integral - bound to membrane surface

Question 7

Passive transport

Answer 7

Diffusion

Facilitated diffusion

Question 8

Active transport

Answer 8

Ion pumps

Endocytosis

• phagocytosis
• pinocytosis
• receptor mediated endocytosis

Question 9

Molecules involved in passive transport (Eg)

Answer 9

Hydrophobic/lipid soluble
O2 CO2
Small polar
H2O, glycerol

Question 10

Molecules involved in active transport (Eg)

Answer 10

Large polar
Glucose sucrose

Ions
Na+ K+ Cl-

Question 11

2 types of facilitated diffusion

Answer 11

Via channels

Via carriers

Question 12

Membranes role in disease

Answer 12

Cystic fibrosis

Question 13

Cystic fibrosis- how why

Answer 13

Defect in cystic fibrosis transmembrane conductance regulator chloride ion channel

Normally transports Cl- ions out of cell

In cystic fibrosis- osmotic gradient not established to draw water out of cell–> thick mucus build up