LIFE 103 1st Edition Lecture 15 Outline of Last Lecture I Solute Transport across Cell Membranes I Active II Passive II Diffusion of water III Plant water facts IV Major pathways of transport V VI I Apoplastic II Symplastic III Transmembrane Soil to xylem Tension cohesion theory Outline of Current Lecture I Ecology the most important field of science very brief not on the exam II Transpiration III Stomata IV Movement of sugars I Source II Sink Current Lecture Resource Acquisition and Transport These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Ecology the most important field of science Why is ecology important I II III IV V Fundamental facts Helps with populations Ecosystem ecology Community ecology Ecology makes use of other fields of science Transpiration review I II III IV Fig 36 14 The atmospheric CO2 concentration is now 400 parts per million has gone up 50 parts per million in our lifetime will be on the test Where is the force generated that draws the water up the plant Through evaporation that pulls up the water water film advances and draws water out of the cell away from the xylem tubes to the wetting surfaces water tension and cohesion Fig 36 15 Resource Acquisition and Transport II I II Fig 35 18 diagram of a leaf Fig 36 16 a guard cell I Stoma space II Used to open and close the vacuoles III Turgid open IV CO2 goes down when the stoma closes Stomata I II III 95 of water loss is via stomata though they cover only 1 2 of leaf area Sausage shape of guard cells maintained by microfibrils Open when guard cells turgid I Turgidity set by active pumping K across plasma and vacuole membranes II Mild drought stress causes guard cells to close I Cues to open guard cells light internal CO2 circadian rhythm III Plants lose water automatically through photosynthesis get water through aqueous reactions probably because they started in the ocean IV Fig 36 17 V When conditions went from wet to dry suddenly potassium would be pumped out Movement of sugars I II Translocation movement of sugars from one part of a plant to another I Sugar source place where sugars are produced II Sugar sink place where sugars are consumed or deposited Transported through phloem I Composed of sieve tube elements that are connected into sieve tubes II Phloem sap the sugary solution that flows through phloem III Trip from mesophyll cell to sieve tubes can be apoplastic or symplastic route IV Water pressure goes up when you add sugar to a cell pushes through the plant s body
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