Plant Transport

Question 1

Factors that influences transpiration

Answer 1

• humidity inc, transp dec (surrounding so much water)
• temp inc, transp inc
• air movement inc, transp inc (evaporate faster)
• flaccid cell, transp dec (stomata close)

Question 2

Features of xerophytes

Answer 2

• thick cuticle: prevent water loss
• trichomes: trap moist air and reduces diffusion
• stomata in pits/groves: moist air trapped in stomata
• leafs are folded: reduced surface area
• leaf area reduced: same, photosynthesis in stem
• reduction in n of stomata: reduces diffusion

Question 3

Adhesion

Answer 3

Attraction of diff molecules

Question 4

Cohesion

Answer 4

Attraction of same molecules

Question 5

Differences between xylem and phloem

Answer 5

1) xylem: transport water and minerals
phloem: transport organic molecules (sucrose, amino acid)
2) xylem: one-way transport
phloem: two-way transport
3) xylem: lignified (water won’t leave from the side)
phloem: thin walls
4) xylem: dead cell
phloem: living cell

Question 6

what does the plant transport system consist of?

Answer 6

xylem and phloem

Question 7

xylem vessel elements

Answer 7

dead empty cells (no end walls) in xylem

Question 8

how does water move from roots to plant parts

Answer 8

mass flow

Question 9

mass flow

Answer 9

a whole body of liquid flow together, individual molecules move randomly

Question 10

features of xylem tissue

Answer 10

• lignified walls (strength and impermeable to water)
• pit in cell wall (allow water out of vessel element)
• dead cells (mass flow)
• xylem fibres - tracheids (strength)

Question 11

features of phloem

Answer 11

• sieve tube elements (living cells, cytoplasm, no nucleus to make space for phloem sap)
• cell wall with cellulose (plasmodesmata links between cytoplasm and companion cell)
• sieve plate (mass flow of phloem sap through sieve pores)
• companion cell

Question 12

features of monocot plant

Answer 12

• 1 cotyledon
• fibrous roots
• vascular bundles scattered
• parallel veins
• petals multiple of 3

Question 13

features of dicot plant

Answer 13

• 2 cotyledons
• tap root
• vascular bundles ringed
• branched leaf
• petals multiple of 4/5

Question 14

why is vascular bundle located in the center of the roots

Answer 14

withstand pulling stains as the plant transport water upwards and grows

Question 15

why is vascular bundle located in the outer part of the stem and xylem tissue near the center?

Answer 15

support plant

Question 16

distribution of xylem and phloem in leaves

Answer 16

vascular bundles form midrib and veins

Question 17

casparian strip

Answer 17

ring of impermeable suberin around endodermis which prevents water from continuing to seep through cell wall

Question 18

suberin

Answer 18

physical barrier that prevents water loss and provide protection against pathogens

Question 19

transpiration

Answer 19

evaporation of water from internal surface of leaves followed by diffusion of water vapour to the atmosphere

Question 20

tension

Answer 20

negative pressure created by evaporation of water from the leaves

Question 21

assimilates

Answer 21

substances made by plants

Question 22

source

Answer 22

a part of the plant where assimilates enter the phloem

Question 23

sink

Answer 23

assimilates leave phloem

Question 24

translocation

Answer 24

transport of assimilates from source to sink (active transport)

Question 25

examples of source

Answer 25

leaves and stem

Question 26

examples of sink

Answer 26

roots and seeds

Question 27

xerophytes

Answer 27

plants live in places with short water supply

Question 28

how is sucrose transported from source to sieve tube element

Answer 28

- photosynthesis creates organic substances including sucrose - sucrose actively transported into sieve tube element using companion cell

Question 29

movement of sucrose within the phloem sieve tube element

Answer 29

- increase in sucrose decreases water potential - water enters sieve tube from xylem by osmosis - increase in water volume in sieve tube, increases hydrostatic pressure which forces liquid down towards the sink

Question 30

transport of sucrose to sink

Answer 30

- sucrose used in respiration at the sink/stored as insoluble starch - more sucrose actively transported into sink cell causes water potential to decrease - results in osmosis of water from sieve tube to sink cell/back to xylem - decrease in the volume of water decreases hydrostatic pressure