Factors

Question 1

Physical properties

Answer 1

Small molecules such as water, o2 and co2 easily slip past passively(co2 and o2 hydrophobic). Use of transport depends on size, if very big go through endocytosis

Question 2

Conc gradient

Answer 2

Rate of diffusion affected by conc of substance on either side, if high then faster, many ways to keep conc gradient steep such as remove wasted/ diffused substances away from tissue of convert to diff substance

Question 2

Size and shape of cell

Answer 2

The greater the substance must travel the slower the rate of reaction is, a large cell would die as the nutrients cannot enter fast enough

Question 3

SA:V

Answer 3

Between sa of membrane and volume of cytoplasm. Need a large sa to v, as you increase the cell size they both increase but v faster than sa

Question 4

RATE is determined by

Answer 4

size and shape of cell, conc gradient

Question 4

shape of cell

Answer 4

some need to be specific shape and size like nerve cells 1 m long, so have things to increase the sa. Spheres have small sa

Question 4

chem properties of a substance

Answer 4

The chem properties indicate how will behave in ext. env and affect its transport. Alcohol cross as its uncharged and dissolve in bilayer. Charged ions are hydrophobic and cannot pass