3.1.3

Question 1

roots TS

Answer 1

X-ylem, phloem, endodermis, cortex, epidermis, root hairs

Question 2

stem TS

Answer 2

parenchyma, xylem, cambium, phloem, cortex, epidermis

Question 3

leaf TS

Answer 3

xylem, phloem midrib, veins, leaf structure

Question 4

phloem summary

Answer 4

dissolved food, both directions
thin cytoplasm vessel with sieve end plate and plasmodesmata to companion

Question 5

xylem summary

Answer 5

water + mineral ion flow up, dead but lignified cell wall with pits (bubbles + sideways)

Question 6

general plant adaptation

Answer 6

SA:V
o2 and co2 produced and used
low metabolic demand

Question 7

water potential of pure water

Answer 7

0

Question 8

symplast pathway

Answer 8

through cytoplasm and plasmodesmata (& vacuole for vacuolar) via osmosis/ diffusion

Question 9

apoplast pathway

Answer 9

along gaps in cell wall/ intercellular space mass flow & cohesion, with ions

Question 10

casparian strip

Answer 10

made of suberin
block apoplast, force symplast
also block pathogen
at the endodermis & xylem

Question 11

how does water move up the xylem

Answer 11

transpiration pull/ cohesion - tension theory
water pressure & capillary action

Question 12

root hair cells and water uptake

Answer 12

actively transport ions to lower water potential
high SA

Question 13

abiotic transpiration factors (5)

Answer 13

light intensity - Δ rate of photosynthesis & transpiration
temp - Δ rate of evap
humidity - Δ vapour grad and hence diffusion
wind - refresh conc grad
water availability

Question 14

biotic transpiration factors

Answer 14

leave shape and number, cuticle
stoma number and distribution (top is hot and windy) pathogens

Question 15

potometer control

Answer 15

cut plant stem underwater
seal joints with vaseline
use healthy plant
dry leaves & acclimatise
support stem

Question 16

xerophyte definition and general adaptations

Answer 16

plant in dry/ arid conditions
CAM (night) photosynthesis
dormancy
Δ leaf, Δ stoma
deep/ wide roots

Question 17

hydrophyte definition and general adaptations

Answer 17

plant in aquatic conditions/ on water
Δ leaf, Δ stoma
less structure (roots and stem)
air sacs and buoyancy

Question 18

mesophyte definition

Answer 18

regular conditions, still adapted though

Question 19

marram grass adaptions

Answer 19

sunken pits and hairs
rolled leaves (hinge)
dense spongy
thick cuticle

Question 20

cacti adaptions

Answer 20

pleats which fill
succulent
spines for water loss and trapping humid air
widespread roots

Question 21

water lily adaptions

Answer 21

stoma on top
air sacs for buoyancy and gas exchange

Question 22

translocation definition

Answer 22

movement of assimilates from source (production) to sink (used/ stored)

Question 23

examples of source to sink

Answer 23

photosynthesising leaves, germinating seeds, spring growth TO
meristematic tissue, seeds/ fruit, active roots and winter tubers

Question 24

active loading of sucrose

Answer 24

H+ actively pumped out companion, H+ and sucrose then move by facilitated co-transporter into companion, plasmodesmata

Question 25

translocation stages

Answer 25

active loading of assimilates at source water enters phloem as Ψ↓ sap moves down pressure gradient (hydrostatic) assimilates diffuse out, water leaves as Ψ↑