2. Lab 5.2: Diffusion Through a Membrane Results
Starch:
Glucose:
Iodine
Iodine
Benedict’s
Starch
BEFORE
Glucose
Iodine
Glucose Only
Heat
Iodine
Only
Benedict’s
+ Glucose
Starch + Iodine
AFTER
Glucose Only
Iodine
Heat
Benedict’s + Glucose

3. Inv. 5.2: Diffusion Through a Membrane
Question of the Day
Question: Explain why farting in an elevator is an example of diffusion. Answer: … … …
More than 25 types of elements
2’s Turn In:
p. 194 A.Q. 1abc 3ab, 4, 5
Inv. 5.2: Diffusion Through a Membrane

4. Announcements Lab Quiz Tuesday Biosphere Observations Test Corrections
1/3 of a point back per question
Last Day: Wednesday, 11/20

5. Quiz! Cell Structures & Functions

7. Unit 4 Vocab

8. Osmosis: Diffusion of Water
Elodea Cells in Water
Elodea Cells in Salt Water
Membrane-bound sac
Important for intracellular digestion, release of waste products
Small in animal cells, large in plant cells

9. Unit 4 Vocab
40. hypertonic- concentration of solutes is high outside of the cell, causing water to leave
Animal Cell:
Above strength
Plant Cell:

10. Unit 4 Vocab
41. hypotonic- concentration of solutes is low outside of the cell, causing water to enter
Animal Cell:
Means below strength
Plant Cell:

11. Unit 4 Vocab
39. isotonic- solute concentrations are equal inside and outside of the cell
Animal Cell:
Same strength
Plant Cell:

12. Why Are Cells So Small? Most cells are between 2µm and 200µm
A micrometer is 1 millionth of a meter!

13. Inv. 5.3: Cell Size & Diffusion

14. 43. surface area- the total area of the outside of an object 44
43. surface area- the total area of the outside of an object 44. volume- the total amount of space inside an object 45. surface area : volume ratio- the amount of surface area per unit volume; helps explain why cells must be small
The volume of a cell increases much faster than its surface area! This causes transport of molecules in and out of the cell to be too slow for the cell to survive!

15. Why Are Cells So Small? Diffusion limits cell size
#57.
Diffusion limits cell size
Larger distance = longer time to get through cell
20 cm cell: months for nutrients to get to the center
Volume increase more rapidly than surface area
What can’t organisms just be 1 giant cell?

16. p. 194 A.Q. 1abc, 3ab, 4, 5

17. p. 194 A.Q. 1abc, 3ab, 4, 5 1a. What is a cell?
1a. A cell is the basic unit of life.
1b. What three statements make up the cell theory?
1b. The three statements that make up the cell theory are:
All living things are made up of cells.
Cells are the basic unit of structure and function in living things.
New cells are produced from existing cells.

18. p. 194 A.Q. 1abc, 3ab, 4, 5
1c. How did the invention of the microscope help the development of the cell theory?
1c. The microscope enabled people to see cells and study the parts of cells. This ability enabled scientists to learn that all organisms are composed of cells.

19. p. 194 A.Q. 1abc, 3ab, 4, 5
3a. What features do all cells have? 3a. All cells have DNA at some time in their lives and all cells are surrounded by a thin, flexible membrane. 3b. What is the main difference between prokaryotes and eukaryotes? 3b. Prokaryotes do not have DNA enclosed in a nucleus. Eukaryotes have DNA enclosed in a nucleus.
Prokaryote:
Eukaryotes:

20. p. 194 A.Q. 1abc, 3ab, 4, 5
4. What is the total magnification of a microscope that has an eyepiece magnification of 10x and an objective lens magnification of 50x?
4. The total magnification is 500x.
A 10 micrometer cell is viewed through a 10x objective and a 10x eyepiece. How large will the cell appear to the microscope user?
5. The cell will appear to be 1000 micrometers (1 mm).

21. When Do Cells Divide? Before they become too big to survive #59.
Mitosis:
What can’t organisms just be 1 giant cell?