movement in and out of cells

Question 1

what is diffusion?

Answer 1

diffusion= the spreading out of particles from an area of a HIGHER concentration to an area of LOWER concentration

Question 2

name 3 things that affect the rate of diffusion:

Answer 2

higher temp & bigger concetration gradient/surface area = faster rate of diffusion

Question 3

what do cell surface membranes do?

Answer 3

hold the cell together but alo subtances to move in & out of the cell

Question 4

why cant starch and proteins diffuse through the cell membrane?

Answer 4

as the molecules are too big

Question 5

what is the cell surface membrane?

Answer 5

a partially permeable membrane=allows diffusion

Question 6

what is the defintion of osmosis?

Answer 6

the movement of water molecules across a partially permeable membrane from a region of a HIGHER water potential to ragion of LOWER potential

Question 7

how do water molecules move

Answer 7

randomly x

Question 8

explain the potato pratical-

Answer 8

1.cut up a potato into equal cylinders and get beakers with diff concentrations of sugar
2.1 should be pure water and 1 should have a high concentration of sugar( u can even get more with 0.2mol/dm3-0.6))))
3.measure the mass of the cylinders - then leave for 24hrs
4.take them out & dry
5.weigh them if mass has increased then water has been aborbed through osmosis
6.cacualte percentage change and plot graph

Question 9

what is the dependent & independent variable in the pataoe pratical?
&control?

Answer 9

the chip mass = dependent
conc of sugar solutions=indeprendent
control-time, temp, volume etc

Question 10

name 2 errors whihc could occur during the patatoe test?
prevent=do repeats

Answer 10

-not of dried potato properly
-water could have evaporated

Question 11

what is active transport?

Answer 11

the mass movement of particles from an area of lower conc to an area of high conc
needs energy

Question 12

what does active transport require?

Answer 12

ENERGY form respiration

Question 13

what do root hair cells use active transport for?

Answer 13

to absorb water to take up mineral ions and (water)

Question 14

how have root hair cells adapted to take up mineral ions?

Answer 14

-large surface area
-thin cell walls
-lots of mitochondria-areobic repiration=energy

Question 15

how do we use active transport in the gut?

Answer 15

nutrients going from a lower conc in the gut to a higherrr conc in blood

Question 16

what can cells use diffusion for?

Answer 16

takin in what the substances they need and get rid off waste priducts

Question 17

whats are the 2 gasses used in gas exchange/ diffusion in plants?

Answer 17

oxygen & carbon dioxide

Question 18

whats the name of a waste proiduct in humans-diffusion?

Answer 18

urea- difuses form cells to blood plasma to kidneys for removal

Question 19

what is the surface are eqiation?

Answer 19

length x width

Question 20

what is the equation for volume?

Answer 20

length x width x height

Question 21

how are exchange surafces adapted to maximiseeffectiveness?

Answer 21

-thin memebrane - shorter diffusion distance
-largee surface area more can diffuse at once
-lots of blood vessels- can get stuff in & out the blood quickly

Question 22

what is the job of the lungs?

Answer 22

to transfeer oxygen ot the blood and remove waste carbondioxide x

Question 23

what are alveoli?

Answer 23

where gas exchange occurs - there are millions in the lungs

Question 24

how have alveoli adapted to maximise diffusion?

Answer 24

-enormous surface area
-moist lining for gass todiisolve
-very thin walls
-good blood supply

Question 25

how have villi adapted to maximise diffusion?

Answer 25

-large suraface area
-thin walls-1 cell thin
-good blood supply to assist quick absorbition

Question 26

where does gas exchange take place in plants?

Answer 26

under leaf in the holes = stomata

Question 27

what diffuses out through the stomata?

Answer 27

-oxygen & water vapour

Question 28

what controls the stomata?

Answer 28

guard cells

Question 29

how have leafs adapted for gas exchange?

Answer 29

flattend shape= increases surface area
air spaces/stomata also gives a bigger surface area - so more CO2 will enter

Question 30

state 3 ways fish gills have adapted for gas exchange?

Answer 30

-large surafce area= gill fillaments covered in lamellae
-thin walls = shorter diffusion didtance
-lots of blood capillaries

note
concentration of oxygen in water is always higher than fishes blood