P1 2h transport in plants Flashcards
what are exchange surfaces in plants?
roots and root hairs
and leaves
what are exchange surfaces in animals?
Alveoli and lungs
small intestines and villi
what are transport system in plants?
xylem - moves water and mineral ions
phloem - moves sugars and amino acids
what are transport systems in animals?
blood and circulatory system
what is the xylem?
vessels that transport water and minerals from the roots to the stem and leaves
what is the xylem made out of?
composed of dead cells which form hollow tubes
- strengthen by lignin
what is the phloem?
vessels that transport food materials made by the plant
what is the phloem made out of?
living cells and are not hollow
what does the phloem transport?
amino acids and sucrose
which way does the phloem go?
it can travel both ways
which way does the xylem travel?
from roots to leaves
bottom to top
where is the phloem in a diagram?
on the outside (on a cross section diagram)
what are root hair cells?
single-celled extensions of epidermis cells in the root
what are root hair cells function?
increase surface area to volume ratio, which increases rate of absorption of mineral ions
how does water move into the root hair cell?
the cytoplasm has a low water potential so it moves into the root hair cell by osmosis
how does root hair cells take in mineral ions?
active transport
how does water move through the plant?
- water move into the root hair cells
- through the root cortex and into the xylem vessels
- then its carried up to the leaves to enter the mesophyll cells
root hair cell - root cortex cells - xylem - leaf mesophyll cells
how do you investigate the pathway of water into and across a root?
by placing a plant like celery into a beaker of water with food colouring
- after a few hours cut the stem and find that certain parts of the celery is stained (only the xylem vessels)
what is transpiration?
the loss of water vapour from the parts of the plant that are above ground level
how does transpiration happen in plants?
- evaporation of water molecules from the surface of the mesophyll cells to air space
- diffusion of water vapour out of stomata (when there is a concentration gradient)
What is the effect of transpiration?
due to transpiration the water in the xylem creates a continuous unbroken column of molecules
- it pulls the water into the xylem vessels
what happens if that rate of transpiration increases?
if rate of transpiration from the leaves increase, water molecules are pulled up the xylem quicker
what is the function of transpiration?
- transporting mineral ions
- providing water to keep cells turgid
- providing water to leaf cells
- keeping leaves cool
what are the factors effecting transpiration?
air movement
humidity
light intensity
temperature
