xylem and phloem

Question 1

what substance do plants need and for what

Answer 1

oxygen
Water
Nutrients sugars
Mineral (nitrate) for proteins and DNA

For photosynthesis, growth and respiration

Question 2

Why do plants need a transport system?

Answer 2

larger plants, have a smaller surface area to volume ratio, so simple diffusion is insufficient

Demand for sugars and water is high

Question 3

What is the function of xylem and phloem?

Answer 3

xylem carries water, insoluble mineral ions, travel up water from the roots to the leaves

phloem carries assimilate, mainly sugars and amino acids, travel up and down the plant from leaves to the rest of the plant

Question 4

How is xylem tissue adapted to its function?

Answer 4

tubes were thick, lignified walls
No cross/end walls
no cytoplasm or cell organelles (dead cells) caused by lignin
Lignin is waterproof, strong and prevents tube, collapsing, spiral, or ringed to allowing flexibility
caps with no lignin (pits) so water can leave the tube into cells
xylem fibre support
Parenchyma packing tissue

Question 5

How is phloem adapted to its function?

Answer 5

Sieve tube elements=
Long, thin, walled cells, lined, end to end
no nucleus little cytoplasm (living)
end walls modified into sieve plates to allow phloem sap to move

Companion cells =
Small metabolically, active cells
Large, nucleus and dense cytoplasm
many mitochondria for ATP for active processes

Question 6

Draw and label a transverse section of a stem

Question 7

draw and label a transverse section of a root

Question 8

Draw and label a transverse section of a leaf