B3 - Movement into and out of cells

Question 1

definition of diffusion

Answer 1

the net movement of particles from a region of their higher concentration to a region of their lower concentration (i.e. down a concentration gradient) as a result of their random movement

Question 2

what are the factors that influence diffusion (4)

Answer 2

surface area
temperature
concentration gradient
distance

Question 3

why is diffusion of gases and solutes important in living organisms (5)

Answer 3

respiration needs oxygen and glucose
glucose and oxygen need to diffuse into the cell
water and carbon dioxide need to diffuse out of the cell
oxygen needs to diffuse out of the lungs into the blood
carbon dioxide needs to diffuse into the lungs from the blood

Question 4

osmosis - what is diffusing and what is it diffusing through

Answer 4

water diffuses through partially permeable membranes by osmosis

Question 5

osmosis description

Answer 5

the net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution), through a partially permeable membrane

Question 6

active transport description

Answer 6

the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration (i.e. against a concentration gradient), using energy from respiration

Question 7

why is active transport important

Answer 7

it is a process for movement of molecules or ions across membranes, including ion uptake by root hairs

Question 8

what are carrier proteins

Answer 8

proteins in the cell membrane that get substances across the membrane using energy transferred from the breakdown of ATP

Question 9

turgor pressure meaning

Answer 9

the pressure inside a cell

Question 10

turgid meaning

Answer 10

when a cell becomes firm or has high turgor pressure

Question 11

flaccid meaning

Answer 11

when a cell becomes soft or has low turgor pressure

Question 12

what happens to a plant when its cells are flaccid

Answer 12

it wilts

Question 13

plasmolysed cell meaning

Answer 13

when a plants cell’s turgor pressure is very low, the cell contents collapse away from the cell wall

Question 14

lysis meaning

Answer 14

animal cells that take in water by osmosis swell and may burst

Question 15

crenated cell meaning

Answer 15

animal cells that lose water by osmosis become crinkled