Transport Systems in plants

Question 1

Transport in unicellular organisms

Answer 1

Diffusion
Fast across short distances
LSA:V

Question 2

Transport in multicellular organisms

Answer 2

Transport systems
Diffusion to center will be too slow
SSA:V

Question 3

Phloem

Answer 3

Transports sucrose and amino acids between leaves and parts of plant
Cells joined end to end
End walls not broken down
Sieve plates
Sieve tube elements has cytoplasm, no nucleus
Companion cell supplies sieve tube elects with requirements
2 way transport system
Thin walls, small lumen

Question 4

Xylem

Answer 4

Drain pipes
Dead hollow cells, joined end to end
Roots, through stem and branch out into leaves
No cytoplasm, nucleus
Walls contain cellulose and lignin
Transport water, mineral salts
Large lumen, thick walls

Question 5

How water is absorbed by root hair cells

Answer 5

Osmosis through root hairs
Pressure difference from transpiration moves water up xylem
Soil, dilute
Cytoplasm, sap, conc

Question 6

Transport of water into xylem

Answer 6

Water travels through xylem, pressure differences
Entry into xylem, high
Cells of leaf, low due to evaporation and transpiration

Question 7

Transpiration

Answer 7

Evaporation of water from plant
In leaves
Cells on inside of leaf covered in moisture
Some evaporates from surface of cells, diffuses out stomata as water vapour

Question 8

Transpiration stream

Answer 8

Water constantly lost from leaves
Water from top of xylem constantly taken from top
Pressure at top reduced, water moves up vessel
Top of xylem=>cells, osmosis
Surface of cell=>spongy mesophyll, evaporation
Air spaces=>out of leaf, diffusion

Question 9

Function of transpiration stream

Answer 9

Supplies water for leaf cells to carry out photosynthesis
Carries mineral ions dissolved in water
Provides water to keep cells turgid
Allows evaporation from leaf surface to keep it cool

Question 10

Factors that affect rate of transpiration

Answer 10

Temp
Humidity
Wind speed
Light intensity
Water supply

Question 11

How plants cut down on water loss

Answer 11

Close stomata
Waxy cuticle, waterproof leaf
Hairy leaves, trap moisture at surface, increase humidity
Stoma on bottom of leaf, cooler and sunken
Cut down on surface area

Question 12

Investigations to see rate of environmental changes on transpiration rate

Answer 12

Potomenter