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Unformatted text preview: B I O L O G Y 1 2 2 3 15-Feb-10 Gardiner 1 Transport in Plants Chapter 29 Water about 75% of earth Water makes up any where from 70 to 90+% of the body weight of living things At most temperatures on the surface of the earth water is a liquid. In this state water is an excellent solvent and because there is so much of it available on the earth's surface water is home (oceans, lakes and rivers) to much of life Review F-13 Cohesion water's hydrogen bonds make liquid water self-sticky this stickiness makes water bead up more on a surface than other substances. Adhesion ability to literally climb the wall of any container it is in. the top of the water column assumes a u- shape called a meniscus. Surface Tension force produced by the difference in hydrogen bonding at water's surface verses its interior, is able to create the illusion that a body of water has a skin. Xylem and Phloem Xylem means wood.-transports water from root up plant-tissue is ded Phloem carries organic nutrients and is alive. As in Fig. 29-7 Fig. 29.2 Sugar from Sugar from photosynthesis photosynthesis Mineral ions a. Short distance transport across cell membranes into roots Minerals Water and solutes from soil enter plant roots by passive or active transport through the plasma membrane of root hairs. Water and mineral ions travel from root hairs into xylem vessels by passing through or between cells (black arrow into/out of xylem). Xylem: transport of H 2 O and O 2 b. Transport in vascular tissues Phloem: transport of sugars Vascular tissue distributes substances throughout the plant, sometimes over great distances. c. Long distance transport throughout the plant Sugar from photosynthesis Cells load and unload organic molecules (including CO2) into and out of phloem (purple arrows to/from phloem). Fig. 29.2 a. Short distance transport across cell membranes into roots Minerals B I O L O G Y 1 2 2 3 15-Feb-10 Gardiner 10 Fig. 29.2 Xylem: transport of H 2 O and O 2 b. Transport in vascular tissues Phloem: transport of sugars Passive and Active Transport Passive transport requires no metabolic energy Substance moves down concentration or electrochemical gradient or by membrane potential Active transport...
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This note was uploaded on 04/18/2010 for the course BIOLOGY 1223 taught by Professor Gardiner/lajoie during the Fall '09 term at UWO.
- Fall '09