9.1 transport systems in dicotyledonous plants

Question 1

What are the 3 main reasons why multicellular plants need transport systems

Answer 1

• metabolic demand
• size
• small SA:V ratio

Question 2

Where’s the vascular bundle in the stem of a herbaceous plant

Answer 2

It’s around the edge to give strength and support

Question 3

Where’s the vascular bundles in the roots of a herbaceous plant

Answer 3

In the middle to help withstand tugging strains from things like the wind

Question 4

What’s the structure of phloem

Answer 4

living tissue, composed of living hollow cells, fused end-to-end to form sieve tube element.

FEW ORGANELLES + COMPANION CELLS
∴ phloem cells rely on companion cells linked to sieve tube elements by plasmodesmata
​contain organelles to carry out cell functions for sieve tube members
SIEVE END PLATES
​perforations in cell wall, allow flow of contents
NO LIGNIN

Question 5

What’s the function of lignin in xylem and why is it in spirals

Answer 5

waterproof vessel, provides support, whilst maintaining flexibility

Question 6

What’s the structure of the xylem

Answer 6

non-living tissue, composed of dead hollow cells, fused end-to-end to form column called xylem vessel.

Lined with lignin in spirals/pits
bordered pits for water to enter/exit laterally
waterproofs vessels + provides support
No end walls

Question 7

What the function of the xylem

Answer 7

It transports water and mineral ions up from the roots to the leaves

Question 8

Where’s the vascular bundle in the leaves of a herbaceous plant

Answer 8

branch out from midrib vein for structural support + transport

Question 9

What’s the function of the phloem

Answer 9

To transport assimilates eg sucrose and amino acids up and down the plant from the sink to the source