chapter 8:tranport in plants Flashcards
function of xylem
transport of water and mineral ions,
and support
What is the structure of xylem
-Thick walls with lignin
-no cell contents
-cells joined end to end with no cross walls to form a long continuous tube
what is xylem walls made out of
cellulose and lignin
what is not fund in xylem
cytoplasm or nuclei
why is lignin important
lignin is very strong,so xylem vessels help keep the plant upright
why is the cells being dead,with no contents important
so that water can flow easily through the tube
why is the cells joined end to end with no cross walls to
form a long continuous tube important
so that there is a continuous tube for water to flow through,all the way from the roots to the leaves
what is a vascular bundle
a group of xylem vessels and phloem
what is the function of root hair cells
to absorb water and mineral ions from the soil
why is there a large surface area in root hair cells
large surface area is important as it increases the rate of the absorption of water by osmosis and mineral ions by active transport
how does water enter the soil
by osmosis because soil water has a higher water potential than the cytoplasm of the root hair cell
describe the partway of water through a plant
root hair cell → root cortex cells → xylem → leaf mesophyll cells
describe transpiration
the loss of water vapour
from leaves
explain transpiration in the leaf
-water moves out of the xylem vessels and into the palisade mesophyll and spongy mesopyll cells by osmosis
-water seeps into the cell walls of the mesophyll cells
-some of the water in these cell walls evaporates
-this produces a very high humidity in the air spaces in the leaf
-the water vapour diffuses out of the air scapes through the stomata into the air
