MASS TRANSPORT IN PLANTS Flashcards
What type of cells are xylem
Dead cells
What type of cells are phloem
Alive cells
Describe and explain xylem cells
Contains pits so water is able to move
Lignin so its waterproof
No end walls so contains continous coumn
Describe and explain phloem
Contains companion cells so no nucleous lr organelles
Transpiration stream
Froom roots to leaves
Describe roots cells
Thinef cell wall
Lots of mitocondria to produce ATP for active transport
Large surface are for channel proteins
How does water enter root cells
Active trasnport of ions using atp
Lower water lotential
Water enters via osmosis
How does water travel from root to xylem
Through endodermis cell
Across cortex
And through epidermis
Descirbe transpiration
Water leaves stomata through evaportaion
Water is pulled from surrounding cells
Creates a tension in xylem
As water is dipolar creates cohesion bwteen water molecules and adhesion as bind to xylem
Creating continous column warer
Hence there is a negative pressure
Why is the stomata close at night
Closed by guard cells
No photosynthesis at night so no need for CO2
Less evaporation of water
Sucrose is moved from where to where
From leaf to roots/flower/stored
Mass flow
Sucrose actively transported into pholem by companion cells
Lowers water potential
Water enters into phloem from xylem by pits in xylem by osmosis down a water potential gradient
Creates hydrostatic pressure which causes mass movement
Sucrose moves out of pholem into roots/flower/stored
Increases water potential water moves from pholem into xylem by osomosis
What is sucrose used for in roots
Converts into glucose for respiration
