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Have your Cell Division packet on edge of desk! Thanks!

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Presentation on theme: "Have your Cell Division packet on edge of desk! Thanks!"— Presentation transcript:

1 Have your Cell Division packet on edge of desk! Thanks!
Learning Goal:1) I can explain the process of diffusion & osmosis and how it’s important to cells. Thinking Skills: Problem solving, main idea Habits of Mind: persisting Have your Cell Division packet on edge of desk! Thanks! Computers ON! Agenda: Feb 13 , 2015 ET #51: Why do you smell odors when you are not necessarily right next to the source? Review Cell Division Explain 28: Osmosis Activity https://www.youtube.com/watch?v=SSS3EtKAzYc https://www.youtube.com/watch?v=SrON0nEEWmo 4) Homework: Complete Osmosis HW? Test Review due Tuesday/ Wednesday after break. Test 2/26 & 2/27; SCaR-NONE

2 ET #51: Why do you smell odors when you are not necessarily right next to the source?
good ppt of osmosis/diffusion

3 Examples of diffusion

4

5 Scientifically speaking, what’s wrong with this Garfield picture?
Let’s quickly and quietly get a RED pen out and log on to the computer. Go to the public/all/kmchenry folder and grade your Cell Division paper, making corrections as needed. You have SEVEN minutes! Work quickly!

6 (difference btwn meiosis & Mitosis) https://www.youtube.com/watch?v=JcZQkmooyPk https://www.youtube.com/watch?v=BkcXbx5rSzw Aging https://www.youtube.com/watch?v=jqCo-McgHLw

7 What is cancer? Out of control mitosis! 

8 EGGS prior to vinegar

9 What’s left on the outside?
#6. Egg Soaked in Vinegar Vinegar causes egg shell (calcium carbonate) to disappear, layer by layer… What’s left on the outside? The membrane

10 EGG prior to and after vinegar

11 Before and After What differences do you notice here?

12 Distilled Water before and after

13 9. The egg in distilled water swelled up! Why?
Draw it! 9. The egg in distilled water swelled up! Why? H2O Protein/fats Because water moved into the egg(high to low) Expanded (swelled up)

14 After #10 Before

15 One shell-less egg soaking in the vinegar was placed in syrup solution.
                                                                            The egg in the syrup shriveled up, water moved out of the egg. (hypertonic)

16 Red Dye Egg before and after
#11

17 12. What is the “Big Idea” here?
Water moves into or out of the eggs depending on the concentration of water inside vs. outside. = moves from High to Low

18 Saltwater is the solution, Salt is the solute Water is the solvent
Solute: “The dissolved substance in a solution” Example: Saltwater Saltwater is the solution, Salt is the solute Water is the solvent Draw different solutes by using different symbols. Example: = water = sugar = salt

19 (Back page)Tap Water Egg before and after

20 (Back Page) Salt Water Egg before and after

21

22

23 Websites to visit to help:
#3a Elodea Leaf (normal)

24 #6a

25 Elodea Leaf in 5% Salt solution

26

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28 Passive Example 2: Osmosis (H2O movement through membranes)

29 ET #47: Show and explain the difference between PASSIVE transport & ACTIVE transport. **passive-no energy required-example: Diffusion

30 Active-goes against the gradient-from low to HIGH. Needs energy!
Dialysis in the kidneys-ACTIVE transport for Sodium ions

31 Diffusion- simple “high to low” movement.

32

33 One solution has a lower concentration of solute than another.
Both solutions have same concentrations of solute. One solution has a higher concentration of solute than another.

34 There are microscopic pores in the membrane.
5 There are microscopic pores in the membrane. Molecules below a certain size can diffuse through the pores. Water molecules can easily diffuse through the pores. In the next slides represents a water molecule and represents a sugar molecule

35 membrane water sugar solution 6
There are as many water molecules on the right as there are on the left but many of them are attached to sugar molecules and are not free to move.

36 Because there are more freely moving water molecules on
7 Sugar molecules can pass through the membrane but, being surrounded by a cloud of water molecules, they move more slowly. Because there are more freely moving water molecules on the left, more diffuse through the pores of the membrane from left to right than from right to left. Molecular movement

37 8 Animation

38 Because the membrane allows only molecules
9 Because the membrane allows only molecules of a certain size to diffuse through it, it is called selectively permeable. The cell membrane functions as a selectively permeable membrane. The cell sap and cytoplasm function as fairly concentrated solutions.

39 The scale of the following drawings is greatly distorted.
Scale of drawings 10 The scale of the following drawings is greatly distorted. Even if the cells were as large as they appear on the screen, the molecules would still be invisible particles

40 Osmosis in animal cells
11 so water diffuses into the cell by osmosis There is a greater concentration of free water molecules outside the cell than inside and the cell swells up

41 If osmosis continued the animal cell would burst
12 If osmosis continued the animal cell would burst This would be bad news for animals Consequently there are processes in the animal’s body which control osmosis Mainly, this is done by keeping the concentration of body fluids outside the cell the same as it is inside

42 As a result the fish takes in water by osmosis
Fresh water fish 14 Trout In fresh water fish, the blood is more concentrated than the surrounding water As a result the fish takes in water by osmosis Not so much through the skin, which is thick, but through the gills which have a very thin membrane

43 The fish gets rid of the excess water by means of its kidneys
14 Perch The fish gets rid of the excess water by means of its kidneys kidneys expel excess water ... blood carries water to kidneys gills absorb water by osmosis ...in the form of dilute urine heart

44 Sea water is a more concentrated solution than the
Sea water fish 15 Herring Sea water is a more concentrated solution than the fish’s blood. What will be the osmotic effect ? A sea water fish will lose water by osmosis through its gills. Sea water fish related to sharks, e.g. dogfish, avoid losing water to their surroundings by maintaining their blood at the same concentration as sea water The fish drinks sea water and the gills expel the excess salt from the blood, so keeping its concentration constant

45 The vacuole will expand, pushing the cytoplasm
16 In a plant cell, the cell membrane acts as a selectively permeable membrane The cell wall is freely permeable to water The vacuole contains a solution of salts and sugars If there is water outside the cell, it will diffuse by osmosis into the vacuole The vacuole will expand, pushing the cytoplasm outwards against the cell wall

46 The cellulose cell wall cannot stretch, so the
17 The cellulose cell wall cannot stretch, so the vacuole cannot continue to expand But the pressure of the vacuole against the cell wall makes the cell very firm A plant cell in this condition is said to be turgid If all the cells in the plant are turgid, the plant will be firm and upright and the leaves would be expanded

47 Plant cells cell wall vacuole cytoplasm and cell membrane
18 cell wall vacuole cytoplasm and cell membrane A useful analogy is the bicycle tyre. The outer casing represents the cell wall; the inner tube represents the cytoplasm and the air inside represents the vacuole. When the tyre is pumped up, the air pressure pushes the inner tube against the outer casing. The outer casing cannot expand and so the pressure in the tube builds up until the tyre is firm The cell absorbs water by osmosis .... ....but the cell wall stops the cell expanding any more

48 Limp and turgid tissue 21 These cells are short of water; the tissue is limp and the plant is wilting The cells have taken up water by osmosis; the cells are turgid and the tissue is firm

49 Busy Lizzie (1) wilting (2) recovering (3) recovered 22
(1) Wilting. The plant is short of water. The leaf cells are no longer turgid and the leaves curl up and droop. (3) Recovered. Water is once more available. The leaf cells take up water by osmosis and become turgid. The leaves are now firm and are held horizontally. Woody plants such as trees and shrubs do not collapse when they wilt but their leaves become limp.


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