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plants chap 13/4
| Question | Answer |
|---|---|
| what are plants exchange surface ? root hairs | |
| what do dicotyledonus root have? endodermis , casparin strip - made of waxy waterproof substance , protoplast , endodermal cell ,xylem ,ploem , cortex. | |
| whqt are root hair responsible for? absorbtion of water and mineral ions. | |
| how to plants lose water mostly? tranpiration: up to 700dm3 per day in large tree. water must be replaced. | |
| how long is root hair cell functional? a few weeks b4 dying. | |
| how is root hair adapted? THIN LONG EXTENSION OF EPIDERMAL CELL LARGE SURFACEA - OCCUR IN 1000S. THIN SURFACE MEM ( THIN CELLULOSE WALL) | |
| Where do root hair cells arise from? epidermal cell | |
| Why does water move via osmosis into root hair cell? root hair cell has sugar aminoA, mineral ions dissolved inside - has LOW WP. | |
| In damp conditions what are root hair surrounded by? soil solution - mineral ions but mostly water. HIGH WP . | |
| what happens after water absorbed into roit hair cell? water continues journey across root via - apoplastic / symplastic pathways. apoplast symplast. | |
| what hqppens in applastic pathway? as water drawn into endodermal cells - pulls water alobg behind it - due to coheive properties. | |
| In the apoplast what does the cohesoin of water cause? tension - which draw water along cell walls of cells of root cortex. cellulose cell walls have mesh like structure - little resistance to pull water ALONG cell walls. - HAS WATER FILLED SPACES. | |
| What is cohesion? is mutual attraction of molecules - ability of molecules e.g. water molecules to stick together. | |
| WP values of SOUTIONS are? negative - water goes from high wp to low wp. - less negative to more negative. | |
| where does symplastic pathway occur? across cytoplams of cells of cortex due to osmosis. | |
| what haps in symplastic pathway? water passes along tiny openings ( PLASMODESMATA). Each PLASMODESMA - filled with strand of cytoplasm - so there is an extensions of the CYTOPLASM from ROOT HAIR CELL to XYLEM at cetre of root. | |
| what does the CASPARIN strip do? It prevents water progressing further along CELL WALL. | |
| As a result of casparin strip preventing water along cell wall? Water is forced into living protoplast of cell - joining water from symplastic pathway. | |
| Where do you find the casparin strip? in the endodermal cell. | |
| How does water get into Xylem ? Active transport of salt into xylem by ENDODERMAL CELLS. need energy . can only occur in LIVING TISSUE. | |
| what do endodermal cells cause when they actively tansport salt into xylem? make a lower WP in xylem . water moves in Xylem via osmosis along a WP grad. | |
| What does the WP gradient made by active transport of salt into the Xylem by the endodermal cell cause? ROOT PRESSURE - which helps move water up plant.- makes diff in herbaceous plants. | |
| when happens when the stomata are open ? water vaour molecules diffuse out air spaces into surrounding air. the atm is less humid than air spaces next to stomata. the atm is less humid than air spaces next to stomata. | |
| how is water lost from the air spaces replaced in plants? replaced with water evaporating from CELL WALLS of surrounding (mesophyll cells). |
Created by:
ufuoma
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