Roots Flashcards
How is a root hair cell adapted?
= densely packed- increaes surface area to volume ratio
= surface of root hair consist only of cell wall and cell membrane- small diffusion pathway
How are mg2+ ions used?
= water in soil contains mg2+ ions dissolbed minerals ions, plants use to make chlorophyll
= concentration is lower in soil compared to root haior, sp root hair cells use actie ranspor- the water potential of the root hair cell is lower than in the soil, water moves into the root hair cell by osmosis down the water potential gradient
Where does water move from?
= from root hair cells to the root corext to xylem
What 2 pathways can water move through?
= symplast pathway.
= apoplast pathway
What is the symplast pathway?
= water moves from the cytoplasm of one cell to the cytopmas of the adjacent cell flows through the plasmadesmata through the cells
= connects cytoplasm of cells
= driven by water pptential gradient of the root hair cells ijn the xylem
=slow pathway
= pathway of water is obstructed by the organelles
=
How is a concentration gradient maintained?
= water continiosly moves intot he root hair cells by osmosus from the soil- higher water ptential compared to cortex
= xylem has a low water potential, water moves by osmosus across corext down the water potential gradient
What is the apoplast pathway?
= water moves within the cell walls and the spaces bwtween the cells
= cellulpse cell walls have a open structure
= water molecules are attracted to eachother- cohesion
= less reistance to water flow to synplast pathwya
=
What is the endodermis cell have?
= befpre water passes into xylem must past the endodermis
= band of water proof material called suberim- casperian strip
= water cannot pass into apoplasy pathway and return to cell membrane and cytoplasm, synplast pathway forcing water to cytoplams, cell mebrane can control what sbstances enter xylem
