In groups of 3, half the class will conduct factors affecting diffusion lab while the others are working on osmosis

Transcription

1 Factors Affecting Diffusion & Osmosis In groups of 3, half the class will conduct factors affecting diffusion lab while the others are working on osmosis 1

2 THE CELL IN ACTION! 2

3 Passive Transport The net movement of a substance across a membrane from an area of high concentration to an area of low concentration. NO ENERGY REQUIRED!! Simple Diffusion, Facilitated Diffusion & Osmosis are examples of Passive Transport 3

4 Day 3 Passive Transport.notebook DIFFUSION 1) Simple Diffusion is the movement of molecules from areas of high concentration to a reas of low concentration. (eg. Air freshener) Allows molecules to directly diffuse through the membrane (eg. O2 & CO2) Before Diffusion After Diffusion There is a higher concentration of oxygen molecules outside the cell than inside the cell. The concentration of O2 molecules is the same outside and inside the cell. 4

5 Diffusion Touch the red divider to watch the dye diffuse and write your observations. Observations: 5

6 Prediction: Diffusion in the Human Body Write your prediction about what happens to oxygen as it diffuses through the body. Erase within the red circles for a hint. Lungs Capillary Cell 6

7 Diffusion 2) Facilitated diffusion uses proteins to assist with allowing molecules to cross the membrane (eg. Glucose) A protein channel & carrier protein is a protein that allows the transport of specific substances across a cell membrane. Remember that a protein is a biological macromolecule made up from a menu of 20 different amino acids (a simple organic compound containing both a carboxyl ( COOH) and an amino ( NH 2) group) and that the sequence of those chains determines the specific shape and function of the protein. 7

8 Another example of passive transport is: Osmosis Tap the image to see osmosis at work. Write your observations. Observations: 8

9 Tea Demonstration Observe the diffusion process in each beaker and describe what happens. a) Does the filter paper of the teabag act as a selectively permeable membrane? Explain. b) Explain how this illustrates Passive Transport. c) How did the temperature of the water affect the diffusion of solutes in each of the three beakers? Water flows by osmosis into the tea bag. You can see this if I remove the tea bag from the beaker and squeeze it to see the water come out. The soluble chemicals within the tea leaves diffuse through the tea bag and into the water; this changes both the color and flavor of the water in the beaker. 9

10 Effects of Osmosis Cell membranes are completely permeable to water, therefore, the environment the cell is exposed to can have a dramatic effect on the cell. The 3 environments are: Isotonic Hypertonic Hypotonic 10

11 Effects of Osmosis ISOTONIC SOLUTION are solutions that have equal solute concentrations, equilibrium has be en reached. When a cell is placed in this type of s olution, the water diffuses. into and out of the cell at the same rate maintaining equilibrium SOLUTE : SOLVENT I SO Perfect?? 11

12 Effects of Osmosis HYPERTONIC SOLUTION is one with a low amount of water outside the cell. Therefore there is a higher concentration of water in the cell than outside it. When a cell is placed in this type of solution, the water diffuses, out of the cell causing the cell to. shrivel This could lead to a condition called CRENATION! HYPER skinny?? 12

13 Effects of Osmosis HYPOTONIC SOLUTION is one with a high amount of water outside the cell. When a cell is placed in this type of solution, the water diffuses, into the cell causing the cell to. swell and possibly explode This could lead to a condition called Hemolysis! HYPO Hippo??? 13

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15 Real Life Applications IV drips! (Infusion of liquid substances directly into a vein) 5% glucose, 0.9% salt this is normal blood IV fluids are commonly organized into three general categories: isotonic, hypotonic, and hypertonic. Providers typically order a solution based on the particular patient s blood electrolyte values. All IV fluids must be administered carefully, but hypertonic solutions are particularly risky. These solutions pull fluid into the vascular space by osmosis, resulting in an increased vascular volume that can result in pulmonary edema, particularly in patients who have cardiac or renal disease. Solutes SUCK... water in or out of cell 15

16 Problem Mrs. Nurse prepared three solutions of salt water (1%, 5%, 9%) and poured them into test tubes marked A, B, C. She forgot to identify which concentration was in which test tube. However, the students decided they could identify the solution by adding some blood cells to the test tubes. The students knew that blood cells have an internal salt concentration of about 5%. They also knew that blood cells are impermeable to salt. They added some blood to each test tube. Later they removed one drop of blood from each test tube and examined the blood cells under a microscope. The blood cells in tube A were greatly swollen, and many membrane had ruptures open. The blood cells in tube B were shriveled up like raisins. The blood cells in tube C had not changed. Determine the percent concentration of the salt in tube A, B, and C and explain your answer. 16

17 Activity Collect data from Factors Affecting Diffusion Factors Affecting Osmosis Complete Questions 17

18 ACTIVE TRANSPORT the movement of substances across the cell membrance from an area of low to an area of high. Cell energy (ATP) is used to move particles through membrane. Types of Active Transport 1) Carrier Proteins using ATP to change their shape allowing particles to be moved against the gradient You Tube Video What are the main differences between passive and active transport? 4:12 Begin at 5:04 18

19 MOVEMENT OF LARGE PARTICLES 2) Endocytosis cell membrane folds around a substance bringing it into the cell. There are two types: a) PHAGOCYTOSIS when the substance engulfs a large particle ex. white blood cell 'eating' bacteria b) PINOCYTOSIS when the substance engulfed is a liquid ex. fluids in solution 19

20 MOVEMENT OF LARGE PARTICLES 3) Receptor Mediated Endocytosis, specific molecules bind to receptor in the membrane vesicle forms as the membrane sinks in, lysosome joins vesicle breaks down substance which now can diffuse into cytoplasm and empty receptor becomes part of the membrane again reusing receptors 20

21 MOVEMENT OF LARGE PARTICLES 4) Exocytosis, the movement of unwanted materials out of the cell by pushing a vesicle to the cell surface. 21

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23 Activity 1) Passive & Active Transport Questions Homework 2) Osmosis Lab Potatoes Wednesday 23