Movement through cell membranes

Question 1

3 processes that move substances through cell membranes

Answer 1

diffusion
osmosis
active transport

Question 2

diffusion definition

Answer 2

the movement of a substance from an area of high concentration to an area of low concentration
a passive process

Question 3

why does diffusion not require energy?

Answer 3

because it moves substances ALONG the concentration gradient

Question 4

what type of substances move by diffusion

Answer 4

liquids and gases

Question 5

1 example of animal diffusion

Answer 5

0₂ and CO₂ between the air in the alveoli and the blood capillaries

Question 6

1 example of diffusion in plants

Answer 6

H₂O vapour moving out of leaves and stems via stomata

Question 7

osmosis definition

Answer 7

the movement of water molecules from a region of high water concentration to a region of low water concentration through a semi-permeable membrane

Question 8

what type of process is osmosis

Answer 8

a passive process

Question 9

what category does osmosis fall into

Answer 9

diffusion

Question 10

selectively-permeable membrane

Answer 10

a membrane that allows free passage of some molecules and prevents the passage of others

Question 11

advantage of a selectively permeable membrane

Answer 11

substances can be let in or substances can be let out or substances can be kept out or substances can be kept in

Question 12

if a cell is surrounded by a solution of higher water concentration

Answer 12

water moves in by osmsos

Question 13

if a cell is surrounded by a solution of lower water concentration

Answer 13

water moves out by osmosis

Question 14

a cell is surrounded by a solution of the same water concentration

Answer 14

it stays the same

Question 15

turgor or turgor pressure

Answer 15

the pressure of the cell contents on the cell wall

Question 16

3 things that turgor does in plants

Answer 16

gives them
shape
strength
support (in woody stems and leaves)

Question 17

what happens if there is no turgor in a cell

Answer 17

it becomes flaccid (limp)

Question 18

what happens if there is no turgor in a plant

Answer 18

it wilts

Question 19

plasmolysis

Answer 19

the shrinking of the cell contents due to the loss of water by osmosis

Question 20

1 plant example of osmosis

Answer 20

absorption of water by germinating seeds

Question 21

1 animal example of osmosis

Answer 21

absorption of water in the intestine

Question 22

why does sugar or salt prevent food decaying

Answer 22

the microorganisms lose water by osmosis as there is a low water concentration outside. they become plasmolysed and die

Question 23

osmoregulation

Answer 23

the maintanence of the water-salt balance in body fluids in organisms

Question 24

the osmoregulatory organs in humans

Answer 24

kidneys

Question 25

the osmoregulatory organs in amoeba

Answer 25

the contractile vacuoles

Question 26

active transport

Answer 26

the movement of substances across a membrane against a concentration gradient that requires energy

Question 27

1 plant example of active transport

Answer 27

absorbtion of minerals by root epidermal cells

Question 28

1 animal example of active transport

Answer 28

reabsorption of glucose, amino acids and salt into the nephron of the kidney

Question 29

to demonstrate osmosis in an artificial membrane

what is the membrane called

Answer 29

visking tubing

Question 30

to demonstrate osmosis in an artificial membrane

what do you first do with the visking tubing

Answer 30

tie a knot at one end

Question 31

to demonstrate osmosis in an artificial membrane

what do you fill the visking tubing with?

Answer 31

strong sucrose solution

Question 32

to demonstrate osmosis in an artificial membrane

what do you fill the control with

Answer 32

distilled water

Question 33

to demonstrate osmosis in an artificial membrane

result for real experiment 2

Answer 33

turgidity increases

mass increases

Question 34

to demonstrate osmosis in an artificial membrane

result for control 2

Answer 34

turgidity unchanged

mass unchanged