Chapter 6

1. Chapter 6 Cells

2. Vocabulary • cell: the basic unit of all living organisms • organelle: structures inside of the cell that have different functions, means “little organ” • nucleus: houses the genetic material of a cell 2 4

3. Vocabulary • unicellular: single celled • multicellular: many cells • membrane: a structure that encloses an organelle 3 5

4. Theories of Life • Theory of Spontaneous Generation – the idea that non-living material produces life. • Aristotle - maggots come from raw meat!

5. Theories of Life • Francisco Redi – Italian Physician – 1668 • Disproved part of spontaneous generation • Placed decaying meat in several jars, those with screens over the top did not form maggots because flies could not land on the meat and lay their eggs.

6. Theories of Life • Louis Pasteur – mid 1800’s • Created an experiment where he cleaned the air of microorganisms and then allowed the air to mix with a broth containing nutrients – nothing grew because it was sterilized! • Theory of Biogenesis – living organisms only come from other living organisms

7. Theories of Life

8. Cell Theory • Three parts • 1. All cells come from preexisting cells meaning cells divide to form new cells • 2. All organisms are made up of cells • 3. Cells are the basic unit of life

9. All organisms are made of cells Cells come from preexisting cells Cells are the basic unit of life 5

10. Think about this! 6

11. Cell Size • Cells are small because they function more efficiently (better) that way • Surface Area: Volume ratio • Smaller cells have more surface area that stuff (volume) on this inside 7

12. Cell Size • Having more surface area allows more stuff to move into and out of the cells • Cells get a lot of their nutrients and materials that way! 8

13. Cell Size 6:1 Means 6 times more surface area than Volume, 6 times more stuff can go through 2:1 Means only 2 times more surface area than Volume, 2 times more stuff can go through ***But the cells is bigger, so what do you think about the amount of nutrients it need? 9

14. So… Who has bigger cells? 10

15. Two Groups of Cells • Eukaryotic: More complex cells • Animal • Plant • Prokaryotic: Less complex • Like bacteria

16. Prokaryotic Cells • very primitive cell • DO NOT have a nucleus (DNA is loose) • DO NOT contain membrane bound organelles • Have ribosomes to make proteins • unicellular (single celled)

17. Eukaryotic Cells • Have membrane bound organelles • Have a nucleus • More advanced than Prokaryotic • Plant and animal cells

18. Cell Structure • ALL cells have plasma (cell) membranes • Kind of like skin • surrounds the cell or organelles • Holds its shape • Plant cells (Euk.) also have a cell wall which helps keep the plant upright

19. Inside the cells • Everything inside the membrane is the cytoplasm • Includes organelles if a Euk., and fluid 15

20. Double Bubble Map Different Different Similar Prokaryotic Cell Similar Eukaryotic Cell Different Different Similar Different Different 16

21. Chapter 6 Cells

22. Parts Inside the Cell 17 17

23. Organelles • Means “tiny organ” in Latin. They are small structures found inside the cell that carry out very important jobs within the cell • Plant and animals cells have many organelles in common but they also have some that are unique to either the plant cell or the animal cell

24. Membranes and Walls • All cells have a plasma membrane that surrounds it • Selectively Permeably: regulates what goes in and comes out of the cell • Animal cells: cell membrane only • Plant cells: membrane and wall • Cell wall is tough and rigid 19 19

25. Cytoplasm • jelly-like substance and all organelles within the cell membrane 20 20

26. Nucleus • The “Brain” of the cell, directs cell activities • Covered by a nuclearenvelope membrane • Porous and allows materials in and out • Contains most of the cells DNA • The DNA contain the information that helps the cell function

27. Nucleolus - makes ribosomes - in the center of the nucleus

28. Ribosomes • Construct Proteins • bound to the Endoplasmic Reticulum • or free floating

29. Endoplasmic Reticulum Rough ER • Covered in Ribosomes • package and export proteins made by ribosomes • Looks like folded ribbon • Smooth ER • No ribosomes • Makes lipids and exports them

31. Chapter 6 Cells

32. The Golgi Apparatus/ Body • “UPS” of the cell • Modifies, stores, and routes proteins and other products • Modifies by enzymes • Looks like flattened stacks of pita bread

33. Vesicle • little packet of material created by the Golgi body to be “shipped” out 27 27

34. Lysosomes • Contain digestive enzymes • Break down old macromolecules for reuse • DNA • Proteins • Polysaccarides

35. Mitochondria • Power Station • Creates the energy (ATP) the cell needs through cellular respiration • ATP: adenosine triphosphate

36. Mitochondria 32

37. Vacuole • PLANTS have a large central Vacuole • Helps with water balance • May contain poisons and pigments

39. Chloroplasts • Only in PLANT cells • Photosynthetic organelles

40. Cytoskeleton • Support skeleton for the cell • Not entirely rigid and can change, unlike our skeleton • Microtubules • Hollow tubes that provide rigidity and shape • Act as tracks organelles can move on • Microfilaments • allow for more movement • Like oozing movement in amoebas

42. Centrioles(Centrosome) • help the cell’s genetic material move during cell division • ANIMAL cells only! 35 35

43. 43

44. Structures for Cell Movement • Flagella • Long and whip like • Used to propel the cell • May rotate or whip around to move • Cilia • Shorter and more numerous • Move in a back and forth motion