Transport

Question 1

What is diffusion

Answer 1

The net movement of a substance from a high concentration to a low concentration

Question 2

What is osmosis

Answer 2

The net movement of water from a high concentration of water (high water potential) to a low concentration of water (low water potential) through a semipermeable membrane.

Question 3

What is facilitated diffusion

Answer 3

When a substance that is too large , polar or charged is assisted passage through a membrane via a specific protein.

Question 4

What protein assists ions / charged molecules through the membrane

Answer 4

Channel proteins form pores to allow ions through

Question 5

What protein allows large long chain molecules through

Answer 5

Carrier proteins

Question 6

What factors effect the efficiency of diffusion

Answer 6

Surface Area
Diffusion distance
Temperature
The smaller and less polar the molecule the easier and faster it diffuses through a membrane
Concentration ratio

Question 7

What is a hypertonic solution

Answer 7

A solution with a low water potential or has been diluted, e g salt water. This means it causes water inside cell to diffuse out of the cell through osmosis. If the cell is an animal cell it will shrivelled up.

Question 8

What is a hypotonic solution

Answer 8

A solution with a high water potential, e g pure water. This means it causes its water to move into cells sometimes causing them to burst or rupture unless they are a plant cell as plant cells have a cell wall which provides structural support.

Question 9

What is active transport

Answer 9

Goes against the concentration gradient (low to high)

Requires energy and is an active process unlike diffusion or osmosis.