3.1.3

Question 1

Why do we need a transport system in plants?

Answer 1

large SA:V ration
rate of diffusion into plants is too slow
high metabolic rate

Question 2

What vascular tissues are involved in plants?

Answer 2

xylem and phloem

Question 3

What is the role of the xylem?

Answer 3

water and soluble minerals move upwards

Question 4

What is the role of the phloem?

Answer 4

sugars move up/down

Question 5

Are there pumps in a plants system?

Answer 5

nO

Question 6

Where are xylem and phloem found?

Answer 6

vascular bundles

Question 7

What does the vascular cambium contain?

Answer 7

meristem cells

Question 8

What is the role of the meristem?

Answer 8

cells undergo differentiation
by mitosis
can differentiate into xylem or phloem

Question 9

What is transpiration?

Answer 9

evaporation of water from the stomata

Question 10

What is the transpiration stream?

Answer 10

movement of water up the xylem

Question 11

How does water enter the leaves in the xylem and pass into the mesophyll?

Answer 11

osmosis

Question 12

What happens after water enter the leaves in the xylem?

Answer 12

passes into mesophyll by osmosis

Question 13

How does water vapour form after water passes into the mesophyll by osmosis?

Answer 13

water evapoarates from the surface of the mesophyll

Question 14

What happens to the water vapour in the spongy mesophyll?

Answer 14

gathers in the air

Question 15

How does water leave the through the open stomata?

Answer 15

water vapour gathers in air spaces in the spongy mesophyll
once water vapour inside the leaf is higher than outside

Question 16

What does transpiration involve?

Answer 16

osmosis from xylem to mesophyll

evaporation from surface of mesophyll into air space in the leaf

diffusion out of the stomata

Question 17

What factors affect transpiration?

Answer 17

temp
humidity
light
air movement
size , position and number of stomata
waxy cuticle
water availability

Question 18

How does temperature affect transpiration?

Answer 18

the higher the temp,

the more KE the water has

so more evaporation of water vapour through stomata

Question 19

How does humidity impact transpiration?

Answer 19

the more water vapour surrounding the stomata

less steep diffusion gradient

so less water leaves leaf by evaporation

Question 20

How does light impact transpiration?

Answer 20

more light

higher rate of photosynthesis

more gas exchange needed

O2 diffuses out of stomata

and CO2 diffuses in

Question 21

How does air movement impact transpiration?

Answer 21

the more wind/air movement

the less water vapour will surround stomata as it will be blown away

so steeper water vapour gradient and

more water leaves stomata by evap.

l

Question 22

How does having stomata at the top of the leaf impact transpiration?

Answer 22

more likely to lose more water by evaporation

because

more build up of water vapour

Question 23

How does having bigger stoamata impact transpiration?

Answer 23

more water leaves stomata through transpiration

Question 24

How does having lots of stomata impact transpiration?

Answer 24

more water leaves stomata by evaporation

Question 25

How does the presence of a waxy cuticle impact transpiration?

Answer 25

waxy cuticle is waterproof thicker so les water will leave by evap.

Question 26

How does water availability impact transpiration?

Answer 26

hydrophytes -> water is readily available so it doesnt matter how much water is lost xerophytes -> uses different ways to conserve water

Question 27

How do you use a potometer?

Answer 27

select a healthy plant cut stem under water at an angle dry leaves set up the potometer introduce an airbubble and set up potometer under H2O

Question 28

What are the control variables for the potometer experiment?

Answer 28

dry the leaves use the same/age species of plant SA of leaves

Question 29

Why do you have to dry the leaves?

Answer 29

avoid reduction in transpiration of water due to water not wantin to leave as much if leaves are wet

Question 30

Why do you cut the stem under water?

Answer 30

avoid any bubbles getting into xylem

Question 31

Why do you cut the stem at an angle?

Answer 31

to increase SA for xylem to take up water

Question 32

Why does the potometer not accuratel measure rate of water uptake

Answer 32

some water can be used in turgor pressure some water used in photosynthesis

Question 33

What data do you need to calculate water uptake?

Answer 33

SA length moved time

Question 34

What type of transport of molecules is the movement of minerals and salts moving into root hair cells?

Answer 34

active transport

Question 35

How does water move into the root hair cell?

Answer 35

There is a lower water potential in the root hair cells due to a higher concetration of solutes water moves into the root hair cells by osmosis

Question 36

Why is there a lower water potential in the root hair cells?

Answer 36

higher concetration of solutes

Question 37

How does water move into the root hair cells?

Answer 37

osmosis

Question 38

Whata are the 2 pathways that water use?

Answer 38

Symplast Apoplast

Question 39

What happens in the apoplast pathway?

Answer 39

Water travels only through cell walls until it reaches the casparian strip

Question 40

What does the casparian strip do?

Answer 40

waterproof layer than forces water to move inside of the cell , inside xylem

Question 41

Where is the casparian strip located?

Answer 41

endodermis

Question 42

What is the symplastic pathway?>

Answer 42

water travels within cytoplasm it travels form cell to cell via the plasmodesmata

Question 43

How does water travel from cell to cell in the symplas pathway?

Answer 43

plasmodesmata

Question 44

What is the cohesion-adhesion tension theory?

Question 45

Where is high hydrostatic pressure according to cohesion -tension theory?

Answer 45

roots

Question 46

Where is low hydrostatic pressure according to cohesion-tension theoru?

Answer 46

leaves

Question 47

What happens as a result of water evaporating formm the smtata according to cohesipon-tension theory?

Answer 47

tension is created in the xylem

Question 48

What gradient does water move up thezylem along in cohesion tension theory?

Answer 48

Hydrostatic pressure

Question 49

How does water move up xylem along hydrostatic pressure gradient?

Answer 49

cohesion adhesion capillary action mass flow

Question 50

What are xerophytes?

Answer 50

plants adapted to reduce water loss

Question 51

Why do xerophytes have rolled leaves?

Answer 51

reduced surface area for evaporation

Question 52

How does having rolled leaves help reduce water loss?

Answer 52

they trap a layer of water vapour

Question 53

What does trapping a layer of water vapour do?

Answer 53

creates a water vapour potential gradient outside the stomata reducing the water vapour potential gradient

Question 54

What does reducing the water vapour potential gradient do for the leaf?

Answer 54

reduces evaporation of water from the leaf

Question 55

How is having hairy leaves an adaptation of xerophytes?

Answer 55

traps a layer of water vapour

Question 56

What does trapping a layer of water vapur arounf a ;eaf help reduce water loss?

Answer 56

creates a higher water vapour potentil outside the stomata reducing thr water potential gradient

Question 57

How does reducing the water potential gradient help reduce water loss?

Answer 57

reduces evaporation of the leaf

Question 58

How does sunken stomata help reduce water loss?

Answer 58

traps a layer of water vapour

Question 59

What does trapping a layer of water vapour do to help reduce water loss?

Answer 59

creates a higher water vapour potential outside the stomat reducing the water vapour potential gradeint

Question 60

How does having needle-like leaves help reduce water loss?

Answer 60

reduces the SA of the leaf so there is less evaporation of water vapour

Question 61

How does having a dense spongy mesophyll layer help to reduce water loss

Answer 61

smaller surface area for evaporation

Question 62

How will stoamata be in xerophytes?

Answer 62

less stomata closed in day' found on lower surface of leaf What will the waxy cuticle be llike?thicker waxy cuticle waterproof prevents water leaving through evaporation

Question 63

What does having a dep root system help reduce water loss?

Answer 63

long deep roots take up water high solute conc in root hair cells

Question 64

What does plant tissue with air spaces in it allow?

Answer 64

buoyancy

Question 65

What are hydrophytes?

Answer 65

plants that live in areas of high water concentration

Question 66

What is beneficial about hydrophytes having large leaves?

Answer 66

large SA to inc rate of photosynthesis

Question 67

How is having long roots that grow out of water a beneficial characteristic for plants?

Answer 67

aids with gas exchange inc rate of photosynthesis

Question 68

Why do hydrophytes have so many stomata?

Answer 68

to aid with gas exchange

Question 69

Where are stomata found in hydriohytes?

Answer 69

upper surface of leaf

Question 70

What is the waxy cuticle thickness in a hydrophyte?

Answer 70

thin

Question 71

How long are the root systems in hydrophytes?

Answer 71

short

Question 72

Why are the root systems short in hydrophytes?

Answer 72

so they are not damaged by current water is readily available

Question 73

What is the source?

Answer 73

where sugars are made or released from starch

Question 74

What are examples of sources?

Answer 74

leafs roots

Question 75

What is a sink?

Answer 75

where sugars are used in respiration or converted for storage so low in concentration

Question 76

What happens in active loading?

Answer 76

H+ in the companion cells are actively transported out into surrounding tissue

Question 77

What happens as a result of H+ being pumped out of companion cells?

Answer 77

H+ conc increases and H+ reenter companion cells

Question 78

How do H+ move back into the companion cell?

Answer 78

cotransporter protein by facilitated diffusion

Question 79

What type of cotransporter protein would be used?

Answer 79

sucrose or amino acid

Question 80

What diffuses through the plasmodesmata and into the sieve tube elements

Answer 80

sucrose

Question 81

What does sucrose diffuse through to get to the sieve tube elements?

Answer 81

plasmodesmata

Question 82

What is the mass flow hypothesis?

Answer 82

sucrose lowers W.P of sieve tube elements so water moves into sieve tube elements from xylem by osmosis

Question 83

What impact does sucrose have on the water potential of sieve tube elements?

Answer 83

lowers W.P

Question 84

What happens as a result of the low water potential in the sieve tube element?

Answer 84

water moves into the sieve tube element from xylem by osmosis

Question 85

How does water move into the sieve tube element?

Answer 85

osmosis

Question 86

What does the osmosis into the sieve tube element cause?

Answer 86

inc in hydrostatic pressure inside sieve tube lements at source

Question 87

How does sucrose leave the sieve tube lements?

Answer 87

diffusion

Question 88

What happens to the W.P after surcrose leaves the S.T.E?

Answer 88

inc

Question 89

What happens in the sieve tube elments when W.P inc?

Answer 89

water leaves by osmosis

Question 90

How does water leave the S.T.E?

Answer 90

OSMOSIS

Question 91

How do assimilates move from source to sink?

Answer 91

down the hydrostatic pressure gradient by mass flow

Question 92

What does the phloem do?

Answer 92

transports assimilates from source to sink

Question 93

examples of assimilates?

Answer 93

sucrose or amino acids

Question 94

Outline translocation?

Answer 94

Hydrogen ions in companion cells are actively transported into the surrounding tissue H+ move back into the companion cell wiht a sucrose