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Chapter 36 www.msbabbey.wikispaces.com Leaves absorb gasses and make sugar Roots absorb water and minerals These items need to be moved throughout a vascular plant www.msbabbey.wikispaces.com Proton Pumps use energy from ATP to pump H+ ions out of plant cells to form an ion gradient This gradient stores energy which can then be used to transport things through a plant www.msbabbey.wikispaces.com Osmosis is the passive transport of water from high to low concentration Water potential (psi) is the combined effects of solute concentration and physical pressure Pure water is 0, whenever you add solute water potential becomes negative (there is less free water in solution) www.msbabbey.wikispaces.com Aquaporins are selective channels in plasma membranes that allow water to cross www.msbabbey.wikispaces.com Vacuoles are the big things in plants that store water The membrane of a vacuole is called the tonoplast www.msbabbey.wikispaces.com When plant cells cytoplasm is connected, this is called symplast When cell walls are connected, this is called apoplast www.msbabbey.wikispaces.com It would take decades for water or sugar to travel from the roots of a redwood to the leaves via diffusion Instead, bulk flow creates pressure which drives fluids www.msbabbey.wikispaces.com Root hairs increase surface area for absorption Mychorrhizae are structures made from symbiotic relationships between roots and fungi www.msbabbey.wikispaces.com The endodermis is the innermost layer of root tissue Located here is the Casparian strip, a waxy layer that is impervious to water and minerals This sets up a selectively permeable membrane; prevents leakage and water loss www.msbabbey.wikispaces.com Plants lose water through their leaves via transpiration Just like you suck water up a straw, water is pulled up xylem as it exits the leaves Cohesion and adhesion allow these sticky water molecules to be pulled up xylem www.msbabbey.wikispaces.com When stomata are open for gas exchange, they also cause water loss (90% of all water loss) In general, they are open during the day and closed at night Stomata are triggered by light; CO2 depletion; and circadian rhythms www.msbabbey.wikispaces.com Sugar is transported in phloem, which is called translocation Sugar travels both up and down a plant’s tubes Sugar moves from areas of high concentration to areas of low concentration www.msbabbey.wikispaces.com