Wk 1- The Cell Membrane

Question 1

Functions of the cell plasma membrane

The cell membrane is the gateway in and out of the cell

• in
• out

Answer 1

Nutrients in

Waste out

Question 2

The cell plasma membrane

The membrane is selectively -
The membrane consists of a - - layer
Hydro-outer
Hydro- inner

Answer 2

Permeable
Phospholipid bilayer
Hydrophilic
Hydrophobic

Question 3

Cell plasma membrane

Passage through the membrane is either p- or a-
P- does NOT require extra -
A- does require extra - in the form of - - -

Answer 3

Passive or active
Passive
Active , ATP

Question 4

Mechanisms of transport through membrane

Passive transport : Diffusion
Diffusion can be either s- or f-

Answer 4

Simple diffusion

Facilitated diffusion

Question 5

Passive diffusion

Simple diffusion: moves through membrane -
Facilitated diffusion: use - channels or carriers to diffuse - the plasma membrane

Answer 5

Freely

Protein , across

Question 6

Mechanisms of transport

Active transport:

Not dependant on - gradients
Requires - in the form of - - -
Uses ion pumps to transport ions across cell membrane : - - pump

Answer 6

Concentration
Energy , ATP
Sodium potassium pump

Question 7

Mechanisms of transport

Vesicular transport :
Movement into and out of cell in sacs called -
Entry into cell = -cytosis
Entry out cell = -cytosis

Answer 7

Vesicles
Endocytosis
Exocytosis

Question 8

Sodium potassium pump

1 molecule of ATP results in - Na+ pumped OUT of cell and -K+ pumped INTO cell

Answer 8

3 sodium

2 potassium

Question 9

Osmosis

The diffusion of - molecules across selectively permeable membrane
Water molecules travel across membrane from - solute concentration gradient to - solute concentration gradient

Answer 9

Solvent
Low concentration
High concentration

Question 10

Tonicity

The effects of - pressure on cells
Solution can be I-, Hypo- or Hyper-

Answer 10

Osmotic

Isotonic hypotonic hypertonic

Question 11

Tonicity

Isotonic= no net flow of water into or out of cell
E- pressure ratio of solvent:solute concentration (E-)

Hypotonic= water flows into cell as cell has higher concentration of solutes
Solute concentration greater - cell , solvent enters cell = swell / l-

Answer 11

Equal
Equilibrium

Inside , lyse

Question 12

Tonicity

Hypertonic= water flows out of cell as cell has lower concentration of solutes
Solute concentration is greater - cell= solvent leaves cell, crenates/ s-

Answer 12

Outside

Shrinks

Question 13

Concentration gradients

Diffusion: movement is - concentration gradient from - to -

Answer 13

Down

High to low

Question 14

Adenosine triphosphate structure and function:

ATP = adenosine and ? phosphate groups 
When energy is used loses ? phosphate and becomes A?P 
1 molecule of ATP results in ? Pump = 
3 ? pumped out of cell 
2 ? pumped into cell

Answer 14

3
1, D 
Sodium potassium pump 
3 sodium Na+ 
2 potassium K+