plants Flashcards
What is a meristem?
A type of tissue found in plants which consists of undifferentiated cells -> found at the GROWING TIPS OF ROOTS where growth is happening
What’s the zone of division?
closest to the root tip.
Made of actively dividing cells (mitosis).
What’s the zone of elongation?
Where the newly formed cells increase in length, thereby lengthening the root.
What’s the zone of differentiation?
Take on identity, become the different cells the plant needs
what do root hair cells do?
They take on water and minerals for the plant. A large surface area helps to do this.
What are lateral meristems?
They’re found in the stems and are responsible for the growth in thickness of a stem.
What are palisade cells?
large number of chloroplastsmakes them the primary site of photosynthesis found near the top of the leaf.
What are guard cells for?
specialised plant cells in the epidermis of leaves, stems and other organs that are used to control gas exchange. Control influx and efflux of CO2 and water from leaves.
what is differentiation?
process where a cell develops new sub-cellular structures to let it preform a specific function
what are the 2 ways a plant can defend itself?
callose production
physical defences
where is callose deposited between?
-cell wall and cell membrane
-sieve plates (phloem) sealing it off and preventing spread of pathogens
-in plasmodesmata stopping the spread to neighbouring cells
physical defences include :
hairs
bark
thorns
drooping leaves
what do hair and thorns do?
Stops the plant from being eaten
what does is bark and what does it do?
external layer of dead cells - physical barrier against infection
waxy cuticle
name 3 chemical defences.
poinsons (deters herbivores)
toxins (warns aphids)
antibacterial (mint witch hazel)
