Membrane Transport

Question 1

def’n transport

Answer 1

movement of materials across a biological membrane
- occurs passively or actively
- involves different mechanisms depending on the permeability of the membrane to a particular material

Question 2

passive transport

Answer 2

movement of material ALONG a concentration gradient (high to low)
- doesn’t require expenditure of energy (ATP hydrolysis)
- 3 types: osmosis, simple diffusion, facilitated diffusion

Question 3

active transport

Answer 3

movement of materials against a concentration gradient (low -> high) requires the expenditure of energy (ATP hydrolysis)
- primary active transport
- secondary active transport

Question 4

osmosis

Answer 4

the net movement of water molecules across a semi-permeable membrane from a region of low solute concentration to a region of high solute concentration (until equilibrium is reached)

Question 5

simple diffusion

Answer 5

• the net movement of molecules from an area of high concentration to low concentration
• directional movement along a gradeint is passive, continues until molecules become evenly dispersed
• rate of diffusion influenced by a number of factors, including: temperature, molecular size, steepness of gradient

Question 6

facilitated diffusion

Answer 6

passive movement of molecules across the cell membrane via the aid of a membrane protein
- utilised by molecules unable to freely cross the phospholipid bilayer (large, polar molecules and ions)
- meditated by channel proteins and carrier proteins

Question 6

channel protein

Answer 6

n/a

Question 7

carrier protein

Answer 7

n/a