Transportation System In Plant Cells

Question 1

Xylem’s Function

Answer 1

transports water and nutrients from roots to leaves so photosynthesis can occur. It is made up of dead and rigid cells

Question 2

Phloem’s Function

Answer 2

transport organic nutrients, primarily glucose from the leaves to other parts of the plant. It can move up and down depending on where nutrients are needed.

Question 3

Root hairs

Answer 3

specialised epidermal cells that are located near the roots

Question 4

Function of root hairs

Answer 4

• increase surface area for maximal absorption
• absorbs water and nutrients from soil

Question 5

Xylem’s Structure

Answer 5

made up of dead, hollow lignified cells. Includes the vessel elements and tracheids

Question 6

Xylem’s Mechanism

Answer 6

Driven by the transpiration system, works due to root pressure, capillary action and transpiration pull.

Question 7

Phloem’s Structure

Answer 7

Made up of living cells, sieve tube elements and companion cells. Sieve plates between the cells allow flow.

Question 8

Phloem’s Mechanism

Answer 8

uses active transport and osmosis in a process called translocation

Question 9

Stomata’s Function

Answer 9

regulates gas exchange and allows water vapour to exit.

Question 10

Structure of Stomata

Answer 10

small pores mostly on the underside of leaves, surrounded by two guard cells.

Question 11

Function of Guard Cells

Answer 11

When potassium ions enter the guard cells which increase the solute concentation, water will follow by osmosis meaning the cells will start to swell which also opens the stomata allowing for gas exchange. However when the plant is dehydrated, it needs to conserve water so the potassium ions will leave the guard cells lowering the solute concentration, water will move out of the guard cells by osmosis causing the cells to become flaccid, which will then close the stomata to reduce water loss.

Question 12

Transpiration Purpose

Answer 12

• Purpose is to pull water and nutrients from the roots to leaves, supplies water for photosynthesis in the leaves.

Question 13

How does Transpiration Work

Answer 13

1. Water Absorption: water enters the roots by osmosis
2. Upward movement: water will move through the xylem vessels via:
   Cohesion: water molecules stick to each other
   Adhesion: water sticks to the xylem walls
   Capillary action and root pressure helps initiate the flow
3. Evaporation: water leaves the leaf via the stomata into the air
4. Transpiration pull: the loss of water creates a negative pressure that pulls more water up from the roots.