Topic 3A- exchange and transport systems

Question 1

the bigger the organism the…

Answer 1

smaller the SA:V ratio

Question 2

volume of a sphere

Answer 2

4/3XpiXr*3

Question 3

how do substances get in and out of a single-cell

Answer 3

diffusion, over the small distance of a cell surface memebrane

meaning it is quick

reletivley large surface area compared to volume

Question 4

how do multicellular organisms move substances

Answer 4

specialised exchange organs

e.g. lungs

Question 5

what is mass transport

Answer 5

efficient systems to carry substaces to and fromtheir individual

in mammals, this is usually refered to the circulatory system

Question 6

2 points- distance and surface area

why can multi-cellular organisms not use diffusion alone

Answer 6

1-cells deep within the body means that there is a big distance between them and the the outside environment
2-large animals have a low SA:V ratio, difficult for enough substances to be exhanged that will meet the large volume of a relitivley small surface area

Question 7

mass transport in plants

Answer 7

transportation of water and solutes in the xylem and phloem

Question 8

how does body size influence heat exchange

Answer 8

having a large volume means there is a big distance for the heat to travel

small organisms need a higher metabolic rate to generate enough heat

Question 9

how does body shape influence heat exchange

Answer 9

a smaller surface area means less heat loss

Question 10

foxes

adaptations for heat loss:

Answer 10

arctic fox-small ears and round fave reduce surface area
african fox- large ears and pointed nose maximising surface area

Question 11

ficks law

what features increase the rate of diffusion

Answer 11

large surface area, short diffusion pathway and concerntration gradient

Question 12

why is water needed in plants

Answer 12

• solvent-allow gases to dissolve
• hydrolysis reactions
• photosynthesis
• make the cell turgid(rigid)

Question 13

pores on the epidermis layer of a plant

Answer 13

stomata

Question 14

what controls the opening and closing of stomata

Answer 14

guard cells

Question 15

why is the mesophyll layer surrounded by water

Answer 15

so the co2 can dissolve

Question 16

why is the mesophyll layer known as ‘spongy’

Answer 16

space within it so co2 can diffuse much quicker to the cells

Question 17

what does a vacuole do

Answer 17

pushes to organelle’s to the side meaning the chloroplasts are compacted to the side

meaning more of chance for light to it them for photosynthesis

Question 18

where does photosynthesis take place

Answer 18

chloroplasts

Question 19

why are plant cells in a pallisade shape

Answer 19

so they can all fit together, resulting in light being more likely to hit a chloroplast

Question 20

opposite

equation for photosynthesis and respiration

Answer 20

carbon dioxide +water <> oxygen +glucose

Question 21

why do stomata close at night

Answer 21

to keep moisture in, photosynthesis isnt happening due to no sunlight

Question 22

what are the pores on insects called

Answer 22

spiricles

Question 23

what are the advantages of insects having an exoskeloton

Answer 23

protection and prevnts water loss

Question 24

what is an insects exoskeleton made from

Answer 24

chitin (B glucose) and a nitrogenous group

Question 25

do insects have a large or small SA:V ratio

Answer 25

small | so cant rely on diffusion alone

Question 26

what system do isnsects use

Answer 26

tracheal system | no lungs

Question 27

order of events of the tracheal system

Answer 27

1. spiricles 2. trachea 3. tracheoles 4. tracheal fluid 5. cell

Question 28

what does the tracheal fluid do

Answer 28

dissolves the gas to be absorbed

Question 29

what increases the rate of gas exchange in insects

Answer 29

anaerobic exersice

Question 30

why do insects use anaerobic exersice

Answer 30

* this produces lactic acid within the cell which decreases the water potential in the cell * meaning the tracheal fluid moves out of the tracheole into the cell * allowing O2 to move quicker into the cell

Question 31

why is it important that the pressure in the tracheoles is low

Answer 31

it allows a larger concerntration gradient from the atmosphere meaning more oxygen is drawn in

Question 32

# tracheal fluid when the insect isnt active...

Answer 32

the fluid seeps from the surrounding cells into the tracheoles

Question 33

when an insect is active...

Answer 33

muscles will draw up the fluid (had dissolved oxygen in it) | for respiration

Question 34

what increases when the tracheal fuid is drawn up when the insect is active

Answer 34

surface area, allowing O2 to diffuse directly through the tracheal walls

Question 35

how do larger insects ventilate the tracheal system

Answer 35

* air sacs- can be squeezed by flight muscles to push air of the the trachae * alteration of the thorax when flying- movement/ expansion of thorax cavity helps draw air in

Question 36

# front and back spiricles what is the specialised breathing mechanism of larger insects

Answer 36

* expand abdomin which close spiricles at the back of the absomin and opens the front ones * abdomin contacts again and the spiricles at the back open allowing CO2 to exit whilst the ones at te front close

Question 37

what do rings of chitin on the trachea do

Answer 37

adds structure, prevents them from collapsing when the muscle contracts for mass transport

Question 38

what is a xerophyte

Answer 38

plants adapted to low water areas

Question 39

what do curved leaves do

Answer 39

they protect the stomata from the wind and so moist air can be trapped on the inside | e,g, marram grass

Question 40

sunken stomata

Answer 40

trap moist air surrounding the stomata meaning the concerntration gradient is reduced to prevent evapourisation

Question 41

reduced no. of stomata

Answer 41

fewer spaces for water to escape

Question 42

thick waxy cuticle

Answer 42

reduces evapourisation

Question 43

layer of hairs surrounding the stomata

Answer 43

further trap most air surrounding the stomata

Question 44

roots | cacti

Answer 44

* deep roots to find further water from lower levels of water * shallow roots which means they can get the water from flash floods quickly

Question 45

what are succulents

Answer 45

plants that ca stare water within their stem

Question 46

spines

Answer 46

* reduced SA:V ratio-so less water loss * can produce some shade as protection from the sun, ruducing transpitration

Question 47

on cacti where is the stomata found | which means ...

Answer 47

on the stem, meaning that is where photosynthesis takes place

Question 48

is water concerntration lower in water or air

Answer 48

water

Question 49

where does gas exchange happen on a fish

Answer 49

gills

Question 50

what is the structure of a gill filament

Answer 50

flatened plates

Question 51

what are the filaments of a gill attached to

Answer 51

gill arch

Question 52

what are on the gill fillaments and why

Answer 52

lamellae- they increase surface area so more oxygen is diffused

Question 53

what do gill rakers do

Answer 53

prevent debris from enetering the fish from the gills

Question 54

what is the operculum | and what does it do

Answer 54

covering over the gills for protection and to make the fish more streamline ## Footnote e.g. this helps with salmon when swimming up stream to reproduce

Question 55

how does oxygen reach the gills

Answer 55

passes through the mouth and filters through the gills

Question 56

how many layers of gill filamets are there

Answer 56

2

Question 57

why wont gills work on land

Answer 57

in thw water it spreads out the lamellae, out of the water they will stick together which decreases the surface area forgas exchange

Question 58

how do fish retain oxygen

Answer 58

counter-current system

Question 59

# in the name! what is the counter-current system

Answer 59

the capillary networkof blood flowing in the opposite direction to the water menaing there is always a diffusion gradientbetween the water and the blood | so oxygen can diffuse into the blood ## Footnote equilibrium is never met