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Do Now, Agenda Take out HW to be checked Work on do now questions

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Presentation on theme: "Do Now, Agenda Take out HW to be checked Work on do now questions"— Presentation transcript:

1 Do Now, Agenda Take out HW to be checked Work on do now questions
Today: Notes, Lab Cell Membrane Quiz/Quest MON 11/23, TUES 11/24

2 Lab Set Up Make initial observations about potato slices & Measure initial mass of potato slices (keep track of which ones will go in each cup) Place potato slices in different salt solutions Return to seats.

3 Solutions Cells are surrounded by watery solutions and are filled by watery solutions. A solution is made up of a solute and a solvent Solute: the substance being dissolved Solvent: the substance that dissolves the solute

4 Solutions The concentration of a solute is important to organisms.
Organisms cannot live unless the concentration of dissolved substances stays within a narrow range. Since many solutes cannot easily move across the cell membrane, the movement of water across the membrane helps to balance the concentrations of dissolved substances (solutes) in a cell

5 Osmosis The passive transport of the movement of water across a selectively permeable membrane. Like other molecules, the movement of water is controlled by differences in concentration(a concentration gradient) Water will move in the direction where there is a high concentration of solute (hence a lower concentration of water) “Salt Sucks”

6 Tonicity Tonicity = the measurement of solute concentration on either side of a membrane. The tonicity of a cell’s environment affects the rate of osmosis (movement of water) across the cell membrane.

7 Hypertonic Solutions Has a higher solute concentration compared to the cell When a cell is placed in this type of solution, water will move out of the cell to achieve an equal concentration of solute inside and outside the cell. This causes the cell to shrink

8 Hypotonic Solutions Has a lower solute concentration compared to the cell When a cell is placed in this type of solution, water will move into the cell to achieve an equal concentration of solute inside and outside the cell. This causes the cell to grow, and sometimes burst

9 Isotonic Solutions Has a similar solute concentration compared to the cell When a cell is placed in this type of solution, water will move in & out of the cell equally to achieve an equal concentration of solute inside and outside the cell. This causes the cell to stay the same size

10 Active vs. Passive Transport
Does not need energy; happens on its own Substances naturally move from areas of high concentration to low concentration Osmosis and diffusion are examples of passive transport

11 Active vs. Passive Transport
Active Transport Requires energy; does not happen on its own Substances are transported from areas of low concentration to high concentration The sodium-potassium pump is an example of active transport

12 Potato Cell Lab


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