Exam Specific

Question 1

How does bilayer contribute to stability of plasma membrane?

Answer 1

Contains cholesterol- regulate fluidity

Hydrophobic region- form bilayer

Question 2

What acts as a barrier to mineral ions?

Answer 2

Phospholipids bilayer

Question 3

How the structure of phospholipid molecule allow for formation of plasma membranes?

Answer 3

Phosphate head is hydrophilic with water.
Fatty acid tail is hydrophobic
Heads orientate towards water- bilayer form

Question 4

How does fluid mosaic model describe structure of plasma membrane?

Answer 4

Phospholipid bilayer
Proteins free to move
Proteins scattered randomly

Question 5

Structure of plasma membrane

Answer 5

Phospholipid bilayer

Cholesterol

Intrinsic and extrinsic proteins

Question 6

Function of intrinsic protein

Answer 6

Communication across membrane
Allow charged particles to pass through membrane

Question 7

What is meant by cell signalling?

Answer 7

Lead to a response
Communication between cells.

Question 8

Width of membrane

Answer 8

7 nm

Question 9

Roles of membrane at surface

Answer 9

Control of molecules entering
Facilitated diffusion
Cel, recognition
Receptor
AVP

Question 10

Role of membrane within cell

Answer 10

Compartmentalisation
Site of chemical reaction
Barrier

Question 11

How do small , non polar substances move out?

Answer 11

Diffuse through phospholipid bilayer.

Question 12

How do large substances enter plasma membrane.

Answer 12

Carrier proteins
Endocytosis

Question 13

How do polar substances move to plasma membrane?

Answer 13

Through pores
Carrier proteins
Facilitated diffusion

Question 14

How do channel proteins work I’m facilitated diffusion

Answer 14

Forms pores
Phospholipid bilayer prevents diffusion
Polar
AVP
Hydrophilic conditions

Question 15

Protein carrier work in facilitated diffusion or active transport

Answer 15

Attach on one side of membrane
Protein change
Release on other side of membrane

Question 16

Differences between active transport and facilitated diffusion

Answer 16

Facilitated diffusion does not use ATP, whereas active transport does.

Facilitated diffusion takes place down concentration gradient, active transport takes place down concentration gradient.

Facilitated diffusion uses both channel or carrier proteins, active transport uses only carrier proteins.

Question 17

Ways substances cross membrane

Answer 17

Osmosis- High WP to low WP gradient
Though channels

Facilitated diffusion- channel/carrier protein, down concentration gradient

Active transport- carrier protein, against concentration gradient, uses ATP

Phagocytosis- engulfing cell membrane to form vesicle

Exocytosis- fusion of vesicles with cell surface membrane

Question 18

What is Endocytosis?

Answer 18

Membrane folding in
Pinches of/ fuses with itself
Formation of vesicle
Requires energy

Question 19

Effect of high temperature on Yeast cell membrane

Answer 19

Phospholipid have more kinetic energy
Increase in gps in membrane
Bilayer more fluid
Proteins denatured

Question 20

Riles of membrane inside cells

Answer 20

Compartmentalisation
Site of attachment for enzymes
Provide selectively permeable membrane
Creation of concentration gradient