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Osmosis and Water Potential. Ch 7 - Principles of Transport/Osmosis and Effects on Cells Ch 36 Osmosis-Water Potential in plants. Problem:. Permeable to simple sugars but not dissacharides . Can we answer Q 6 a-e on page 141?. Environment: 0.01 M sucrose 0.01 M glucose 0.01 M fructose.
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Osmosis and Water Potential Ch 7 - Principles of Transport/Osmosis and Effects on Cells Ch 36 Osmosis-Water Potential in plants
Problem: Permeable to simple sugars but not dissacharides. Can we answer Q 6 a-e on page 141? Environment: 0.01 M sucrose 0.01 M glucose 0.01 M fructose “Cell”: 0.03 M sucrose 0.02 M glucose
“Tonicity” drives direction of water movement • Hypertonic • Hypotonic • Isotonic
Effects on Cells • Plant cells--What adaptations do plant cell have to deal with water balance? • Vocab: turgid, flaccid, plasmolysis • Animal cells • Vocab: lysis
Freshwater adaptations that prevent cell lysis • Freshwater Fish…drink a little, but pee a lot • Protista…contractile vacuole (eg. Paramecium)
Ch 36 - Adaptations for Resource Acquisition • Private Life of Plants excerpt:Perfect Pumps
What drives the movement of water? • What is this a picture of? (hint: a major plant organ) • What adaptations do plants have to control the route water takes?
Cell wall Apoplastic route Cytosol Symplastic route Transmembrane route Key Plasmodesma Apoplast Plasma membrane Symplast Three routes of transport • Apoplastic - external to cell membrane, through walls and spaces • Symplastic - through cytoplasm and plasmodesmata • Transmembrane - passage across cell membranes and walls
Investigating Solute Movement • Water follows ions…but how do ions become concentrated. • Active Transport • We will also discuss this in relation to the human kidney • Ch. 8 147-151 • Ch. 44 936-953
Water Potential • Tendency of water moves from areas of higher water potential to lower water potential. • Water potential= pressure potential plus solute potential
Turgor Pressure • Plant cell walls exert pressure on the cells • Turgid = Healthy state
Water potential in a Hypertonic Solution • Why is the cell losing water? • What is the end result--what happens to the water potential inside/outside the cell?
Water potential in a hypotonic solution? • What happens to the cell over time? • Where is the water potential greater to begin? • Which direction does the water move?
Loss of water drives movement • Loss of water from stomata • Cohesion-tension hypothesis • Movement by Bulk Flow • Online - Transpiration Case Study
Regulation of Transpiration • Where would we find guard cells ? • Can you explain picture B using the concept of water potential?
Review the Concept of Water Potential Background research: • Osmosis Lab Bench • Case Study 36: How are Water and Solute Potentials Calculated
Lab: • As a class, we are going to compare water potential of different plant parts: • Roots, Stems, Tubers, Leaves, Fruit • Each group will develop a standard curve to estimate the water potential of their assigned plant part. • You will be able to make a 1 M sucrose solution, and then you will use serial dilutions to make known sucrose standards.
How to use sucrose concentration to solve for water potential?
What will you use for concentration? • What will your indepedent and dependent variables be? • What can you use your standard curve to solve for?