Transport

Question 1

What is diffusion

Answer 1

The net movement of molecules from an area of high to low concentration until the modules are equally distributed

Question 2

Why is diffusion a passive process ?

Answer 2

It does not require energy from respiration

Question 3

What is Ficks law

Answer 3

the rate of diffusion is proportional to :
SA x Difference in concentration
———————————————
length of diffusion pathway

Question 4

Simple diffusion

Answer 4

Large charged molecules cannot cross the phospholipid bilayer by simple diffusion + require transport proteins
- Small little/mo charge molecules can pass between phospholipids - lipid
soluble molecules
Water passes through aquaporins
(protein channels) by osmosis

Question 5

What is facilitated diffusion

Answer 5

Allows the transport of water soluble eg polar molecules such as glucose and amino acids across the membranes
- Uses channel proteins + carrier proteins with specific shapes and hydrophobic groups
- Passive process

Question 6

What do carrier proteins do

Answer 6

they change shape as they move water soluble materials

Question 7

What are protein channels

Answer 7

have a fixed shape
transport ions
the charge present in the channel makes the channel specific for a certain ion
the pore size will also determine which ion can pass through the channel proteins

Question 8

What is Active transport

Answer 8

Active transport is the movement of molecules or ions through a selectively/partially permeable membrane by carrier proteins against a concentration gradient