C3- Transport

Question 1

Absorption by roots and transport to xylem

Answer 1

Active transport of minerals into the roots causes water to move into the roots by osmosis
- Root hairs increase SA

Question 2

Bulk Transport from roots to leaves (3 Mechanisms)

Answer 2

Root pressure- accumulation of water in root xylem that pushes sap up stem towards the leaves (minor mechanism)

Transpiration pull- created by water evaporation as water is pulled up tissue to replace the water lose through transpiration

Cohesion- Tendency of water molecules to stick to other water molecules
-Pulls a column of water up to leaves

Adhesion- tendency of water molecules to stick to certain surfaces
-prevents sap from falling back down (resist’s gravity)

Question 3

Steps in sugar transport

Answer 3

Loading of Sugar- sugars produced by sugar source are transported to phloem vessel by active transport

Uptake of water- osmosis causes water to move into the phloem vessel increasing pressure inside the vessel

Bulk transport- pressure and concentration gradients move the phloem sap toward the sugar sink

Unloading of sugar- increasing pressure forces the phloem sap out the vessel into neighbouring cells

Question 4

Gas Exchange (Leaves)

Answer 4

Most gas exchange occurs through stomata in epidermal layer
- CO2 is transported into leaf and O2 is transported out through passive transport

Question 5

Gas Exchange (Stems and Roots)

Answer 5

Lenticles- Lense shaped opening in bark of woody plants that enable gas exchange

Question 6

Transpiration

Answer 6

Loss of water through diffusion and evaporation
- Large sa, High sa/v ratio and stomata important for photosynthesis but also increase water loss

Question 7

Controlling stomata

Answer 7

Open- in moist environments guard cells open all
-gain water, become turgid and open

Close- in dry environments guard cells close
-lose water, become flaccid and close