4.5 Flashcards
Mads/ Sarah
what are sclerenchyma and xylem vessels made up of
They’re both made up of bundles of dead cells that run vertically up the stem
Both the sclerenchyma fibres and xylem vessels provide ——- to the plant.
support
what are the primary funtions of stem?
support and transport
what are parentchyma cells and what is their function?
unspecialised cells that act as packing in stems and roots to give support
what are collenchyma cells and what is their function?
plants cells with areas of cellulose thickening that give mechanical strength and support to the tissues
what are sclerenchyma cells and what is their function?
plant cells that have very thick lignified cell walls and an empty lumen with no living contents
what is the function of the epidermis?
to proctect tissue
What do xylem vessels transport?
Water and solutes such as salts/ mineral ions
What do phloem vessels carry?
The phloem carries sucrose, soluble sugars and organic compounds
What is the difference between the structure of sclerenchyma fibres and xylem vessels?
Sclerenchyma fibres are short and tapered with closed ends, whilst xylem vessels are cells joined end to end with their end walls broken down to allow vertical transport of water
Where is the xylem, phloem and sclerenchyma located in the stem?
The xylem is located in the inner part of the stem, the phloem is located in the middle and the sclerenchyma is located in the outer part of the stem
Which one contains living cells, xylem, phloem or sclerenchyma?
Phloem- it does not contain lignin so cells live.
Why dies the xylem and sclerenchyma contain dead cells?
Because they contain lignin.
The cells in the phloem need to be alive to provide energy for active transport when transporting sucrose around the plant.
What is translocation?
the active process in phloem, movement of organic solutes up and down the stem
What are companion cells?
Cells found in phloem, that link to sieve tubes with many plasmodesmata. They are active cells (many mitochondria) that support the sieve tube cells.