Tuesday, 10/17: Fun with tonicity Please answer these questions independently. Also, please DO NOT turn in the worksheets to the bin. You will need those to help you with our Foldable. 1.) In a ______ (hypo-, hyper-, OR isotonic) solution, the total concentration of solute molecules is less than that of another environment/the cell. 2.) In a ______ (hypo-, hyper-, OR isotonic) solution, the total concentration of solute molecules is greater than that of another environment/the cell. 3.) In our diffusion lab, the ____ (beaker OR bag) had a greater concentration of iodine molecules relative to another environment. 4.) In our diffusion lab, the ____ (beaker OR bag) had a greater concentration of starch molecules relative to another environment.

Today’s activities + Homework Today: 1.) Review tonicity (especially as it pertains to our lab) 2.) Review the two “Cell Transport” worksheets (any specific questions?) 3.) Begin “Tonicity Foldable” (we will finish in class on Wed/Thurs) Homework: 1.) Continue reviewing Chapter 5 notes (may do Kahoot! Wed/Thurs) 2.) I will be posting a Chapter 5 Study Guide on Wed. or Thurs. PRINT IT to work on it in class on Friday, 10/20 3.) Chapter 5 “Quizlet” on Tuesday, 10/24

Word of the day Moribund (adj.) In a dying state; near death. On the verge of extinction or termination. “Without water, the plants will soon enter a moribund state.”

Osmosis is a type of diffusion Diffusion: Movement of substances (other than water) across a semipermeable membrane from an area of high concentration to an area of low concentration. NO ENERGY required (passive transport). Osmosis: Movement of ONLY water across a semipermeable membrane from an area of high concentration to an area of low concentration. NO ENERGY required (passive transport).

Hypotonic solutions In a HYPOTONIC solution, the total concentration of solute molecules is less than that of another environment/the cell In our lab, the iodine was in the bag and the starch was in the beaker The Question: In relation to the starch, is the baggie or the beaker hypotonic? Put Another Way: Where is the total concentration of solute molecules (in this case, the starch) less than that of the other environment? The Answer: The baggie. Less starch here in comparison to the beaker. Lower concentration of starch solute.

Hypertonic solutions In a HYPERTONIC solution, the total concentration of solute molecules is greater than that of another environment/the cell In our lab, the iodine was in the bag and the starch was in the beaker Question #1: For the iodine solution, is the baggie or the beaker hypertonic? Put Another Way: Where is the total concentration of solute molecules (in this case, the iodine) greater than that of the other environment? The Answer: The baggie. More iodine here in comparison to the beaker. Greater concentration of iodine solute.

Hypertonic solutions (continued) In a HYPERTONIC solution, the total concentration of solute molecules is greater than that of another environment/the cell In our lab, the iodine was in the bag and the starch was in the beaker Question #2: For the starch solution, is the baggie or the beaker hypertonic? Put Another Way: Where is the total concentration of solute molecules (in this case, the starch) greater than that of the other environment? The Answer: The beaker. More starch here in comparison to the baggie. Greater concentration of starch solute.

Hypotonic environments and osmosis in cells In a HYPOTONIC solution, the total concentration of solute molecules is less than that of inside the cell Less solute in the outside environment, more solute inside the cell If there is less solute outside the cell, there is also more water outside the cell There is more solute inside the cell, so there is less water inside the cell Water will rush into the cell, going from an area of high water concentration to an area of low water concentration

Hypotonic environments and osmosis in cells (cont.) The Question: Where is the total concentration of solute molecules less than that of the other environment (inside the cell)? The Answer: Outside the cell = hypotonic (less concentrated environment of solute) Water rushes INTO cell (high to low). Animal cell swells and can burst (cytolysis). Plants cells are happy in this environment.

Hypertonic environments and osmosis in cells In a HYPERTONIC solution, the total concentration of solute molecules is greater than that of inside the cell More solute in the outside environment, less solute inside the cell If there is more solute outside the cell, there is also less water outside the cell There is less solute inside the cell, so there is more water inside the cell Water will rush out of the cell, going from an area of high water concentration to an area of low water concentration

Hypertonic environments and osmosis in cells The Question: Where is the total concentration of solute molecules greater than that of the other environment (inside the cell)? The Answer: Outside the cell = hypertonic (more concentrated environment of solute) Water rushes OUT OF cell (high to low). Cell shrivels up. Plants = plasmolysis (plasma membrane pulls away from the cell wall).

AND LET’S NOT FORGET….ISOTONIC Equilibrium Water moves in and out of the cell at a constant rate Happy animal cells 