1. Chapter 7 Cells

2. K – W – L Know-Want to know - Learned

3. Cells Warm Up Journal K – W – L Know-Want to know - Learned Journal: What do you know about Cells… Journal: What do you want to know about Cells…

4. What is a cell? A cell is the smallest unit of life that can carry on all the functions of life.A cell is the smallest unit of life that can carry on all the functions of life.

5. Who first discovered cells? An English scientist looked at cork with an early light microscope; they reminded him of the rooms or “cells” where monks lived. Robert Hooke

6. Who first observed living cells? Anton van Leeuwenhoek in 1673 He viewed pond water organisms and called them “animalcules” or “Wee beasties”. –We now call them protists.

7. What are the three parts of the cell theory? 1. All living things are made of one or more cells 2. Cells are the basic units of structure & function in all organisms. 3. Cells come only from the reproduction of existing cells.

8. With better microscopes, scientist observed structures inside of cells…. Organelles- small structures with in the cell that perform specific functions. Cells can be divided into two groups, those that contain membrane bound organelles and those that do NOT!!!!

9. What are the two types of cells? Eukaryote - cells that have a nucleus and membrane-bound organelles. Examples: plant and animal cells Prokaryote cells that do not have a nucleus and membrane-bound organelles. Examples: bacteria

10. Cells Mind Map Prokaryotic Eukaryotic 2 types Do Not have membrane bound organelles Have membrane bound organelles AnimalPlant

11. Journal: How are eukaryotes different from prokaryotes? (Use a complete sentence) Eukaryotes are different from prokaryotes because eukaryotes -------- and prokaryotes -- -----. What are the 3 parts of cell theory?

12. Inside a living cell there is constant activity. A cell has many parts that work together to accomplish the functions of life. –In eukaryotic cells, many of these molecules are organized in tiny organelles that perform specialized functions inside the cell. Cell Structure and Function

13. The 3 main parts of the cell? 1. Cell Membrane (Plasma Membrane) - controls which substances pass in and out of the cell. 2. Nucleus- contains the hereditary information and directs most of the cell’s activities. 3. Cytoplasm- the region between the cell’s nucleus and the cell membrane, which contains the organelles and the cytosol (jelly-like substance)

14. Journal In your own words, describe the “job” for each of the 3 main parts of the cell Cell membrane: Nucleus: Cytoplasm:

15. What is the cell membrane’s structure and function? Cell membranes help organisms maintain homeostasis by controlling what substances may enter or leave cells.

16. Journal Review What is homeostasis???

17. Selectively permeable Allows some molecules to pass while others are kept out Why might this be important????

18. Structure of the plasma membrane Phospholipid bi-layer –Polar head (hydrophillic - water loving) –Non-polar tail (hydrophobic- water fearing)

19. Structure of the plasma membrane Phospholipid bi-layer –Polar head (hydrophillic - water loving) –Non-polar tail (hydrophobic- water fearing) The two layers are arranged so that polar heads face outside (water) and the tails are on the interior.

20. Within the phospholipid bi-layer there are proteins and cholesterol –Proteins Channels for transport Signal receptors (receive messages from outside of the cell) –Cholesterol Stabilizes the plasma membrane

22. Surface Area to Volume Ratio

23. The rate of diffusion into and out of a cell is proportional to the surface area of the plasma membrane. Diffusion can only supply adequate amounts of nutrients if the surface-area-to-volume ratio is large enough. As cell size increases, the rate of diffusion from the plasma membrane to the center decreases and the surface-area-to-volume ratio decreases. This is a very important reason why most cells are tiny.

24. Now Onto Organelles