9.1 Flashcards
1
Q
Why do multicelluar plants need transport systems?
A
- Metabolic rate- the cells of the green parts of the plant make their own glucouse and oxygen by photosynthesis but other internal and underground parts do not photosynthesise.
Oxygen and glucouse needs to be transported to them and the waste products of cell metabolism removed. - Hormones made in one part of the plant needs to be transported to area where they have effect
- Mineral ions abosrbed by the root transported to cells to make protiens required for enzymes and the structure of the cell.
2
Q
What is the second reason why plants need transport systems?
A
They are large so need effective transport systems to move substances both up and down from the tip of the root to the topmost leaves and stem
3
Q
Why do plants need transport systems?
A
They have a relatively low surface area to volume ratio
Cannot rely on diffusion alone to supply cells as it would be too slow
4
Q
What is the function of the xylem vessel?
A
- Transport water and mineral ions
- For support
- Flow of materials in xylem from roots to shoots/leaves
- Made up of several dead cells with no cytoplasm (long hollow structure)- there is no end wall so it is an uninterupted tube
5
Q
What are the adaptations of xylem?
A
- thick lignin walls found in spirals around the lumen which supports the xylem vessel and prevents it from collapsing inwards from the transpiration pull
- small unlignified areas called bordered pits where water and ions leave the xylem and move into other cells of the plant.
6
Q
What is the function of the pholem?
A
- living tissue
- transports organic solutes such as amino acids and surcouse from the leaves (photosynthesis) to the cells in the rest of the plant for celluar respiration and synthesis of other useful molecules.
- flow of materials is up or down the plant
- like xylem, we have pholem sieve tube joined end to end to form a long hollow structure (not lignified)
7
Q
What is the structure of the pholem?
A
