Movement in and out of cells TOPIC 1

Question 1

Define diffusion

Answer 1

Diffusion is the net movement of particles spreading out from an area of higher concentration to an area of lower concertation, until equilibrium is reached

Question 2

can diffusion happen in solids

Answer 2

no, it only happens in solutions and gases

Question 3

what is the conenratation gradient

Answer 3

the difference in concertration

Question 4

how can you make diffusion happen quicker

Answer 4

• bigger concentration gradient
• higher temperature
• shorter distance to travel
• larger surface area to volume ratio
• larger surface area

Question 5

why does heating cause diffusion to happen quicker

Answer 5

the particles gain more energy, so they move faster

Question 6

what type of process is diffusion

Answer 6

it is a passive process

Question 7

what is a passive process

Answer 7

it means that it requires no energy input

Question 8

how have multicellular animals adapted to increase diffusion

Answer 8

Villi in the small intestine increases the surface area

Question 9

why does increasing the surface area speed up diffusion

Answer 9

because it means that more molecules can cross the membrane in any given period of time

Question 10

What are the ways molecules transport

Answer 10

• diffusion
• osmosis
• active transport

Question 11

what type of molecules can diffuse

Answer 11

small molecules like oxygen, larger molecules cannot

Question 12

how have multicellular plants adapted to increase the rate of diffusion

Answer 12

root hair cells at the tips of the plant roots increase the surface area

Question 13

why can unicellular organisms diffuse directly into or out of a cell

Answer 13

because they have large surface area to volume ratio

Question 14

How is the cell membrane adapted for diffusion

Answer 14

it is partially permeable that let some molecules through

Question 15

is osmosis a passive process

Answer 15

yes

Question 16

what is an isotonic solution

Answer 16

a solution that has the same solute concentration as another solution

Question 17

what is a hypertonic solution

Answer 17

a solution that has a higher solute concentration than another solution

Question 18

what is a hypotonic solution

Answer 18

a solution that has a lower solute concentration than another solution

Question 19

what is osmosis

Answer 19

the movement of water molecules across a partially permeable membrane from a region of higher water concertation to a region of lower water concertation, until equilibrium reached

Question 20

what is water concertation

Answer 20

the measure of how concentrated the water is in a solution

Question 21

if a plant cell is put into a hypertonic solution what will happen to the water in the cells

Answer 21

the water in the cells would leave causing it to die and become plasmorised

Question 22

what do you call a plant cell where all of the water has left it and it has shrunken

Answer 22

plasmolised

Question 23

what do you call a plant cell where water has entered it

Answer 23

turgid

Question 24

what would happen to the water if a plant cell was put into a hypotonic solution

Answer 24

the water outside the cell would move into it

Question 25

What is active transport

Answer 25

the movement of particles from a region of lower concerntration to a region with higher concerntation against the water gradient, using enrgy from respiration

Question 26

Is active transport a passive process

Answer 26

no

Question 27

how do plants use active transport

Answer 27

by pumping in mineral ions because they are present in lower concentrations in the soil than in the root hair cells

Question 28

how do animals use active transport

Answer 28

by the villi pumping glucose and amino acids into the blood from the gut

Question 29

what does the surface area : volume ration determine

Answer 29

how easily stuff moves between an organism and its environment

Question 30

what will the surface area : volume ratio be like for a larger organism

Answer 30

Small

Question 31

how do you calculate the surface area of an organism

Answer 31

top and bottom areas + four sides areas

Question 32

how do you calculate the volume of an organism

Answer 32

length x width x height

Question 33

what organisms need exchange surfaces

Answer 33

multicelluar

Question 34

how have exchange surfaces adapted to make them more efficient

Answer 34

• thin
• large surface area
• good blood supply
• ventilate

Question 35

How do the lungs make gas exchange more efficient

Answer 35

• clusters of alveoli
• large surface area
• rich blood supply

Question 36

why do organisms have exchange surfaces

Answer 36

becuase they neeed a special exchange surface for efficient diffusion due to a smaller surface area : volume ratio so not enough substance can diffuse

Question 37

How do you calculate % change in mass

Answer 37

% change in mass = (change mass / original mass) x 100

Question 38

What can you use to investigate osmosis

Answer 38

Potatoes and putting them in different salt solutions

Question 39

How can you investigate surface area : volume

Answer 39

Using agar and 3 different sized cubes, by placing them in acid the acid will diffuse into the cube removing the pink dye

Question 40

How is the small intestine adapted to maximise diffusion

Answer 40

• thin lining
• lots of capillaries
• lots of villi

Question 41

What diffuses out of cells

Answer 41

Urea

Question 42

How are fish gills adapted for exchange substances

Answer 42

• many gill filaments ~ large surface area
• thin gills
• good blood supply

Question 43

Give two examples in multicellular animals which have adapted to increase diffuse

Answer 43

• alveoli in the lungs: larger surface area for oxygen to diffuse faster
• villi in the small intestine: larger surface area for faster diffusion, thin walls for short pathway