1. Cell Structure Chapter 4

2. 2 Cell Theory Cells were discovered in 1665 by Robert Hooke. Early studies of cells were conducted by - Mathias Schleiden (1838) - Theodor Schwann (1839) Schleiden and Schwann proposed the Cell Theory.

3. 3 Cell Theory 1. All organisms are composed of cells. 2. Cells are the smallest living things. 3. Cells arise only from pre-existing cells. All cells today represent a continuous line of descent from the first living cells.

4. 4 Cell Theory Cell size is limited. -As cell size increases, it takes longer for material to diffuse from the cell membrane to the interior of the cell. Surface area-to-volume ratio: as a cell increases in size, the volume increases 10x faster than the surface area

5. 5 Cell Theory Textbook pg. 60

6. 6 Prokaryotic Cells Prokaryotic cells lack a membrane-bound nucleus. Two types of prokaryotes: -archaea -bacteria

7. 7 Prokaryotic Cells Prokaryotic cells possess -DNA -cytoplasm -plasma (cell) membrane -cell wall -ribosomes -no membrane-bound organelles

8. 8 Prokaryotic Cells Textbook pg. 63

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10. 10 Prokaryotic Cells Flagella -present in some prokaryotic cells -used for locomotion

11. 11 Prokaryotic Cells Textbook pg. 65

12. 12 Eukaryotic Cells Eukaryotic cells -membrane-bound nucleus -cellular functions occur within organelles -cytoskeleton for support

13. 13 Textbook pg. 66 Eukaryotic Cell (animal)

14. 14 Eukaryotic Cell (plant) Textbook pg. 67

15. 15 Eukaryotic Cell Organelles Nucleus -stores the genetic material (DNA) -surrounded by a nuclear envelope composed of 2 phospholipid bilayers

16. 16 Eukaryotic Cell Nucleus Textbook pg. 68

17. 17 Ribosomes -the site of protein synthesis in the cell -composed of RNA and proteins -free-floating or attached to E.R. Eukaryotic Cell Organelles

18. 18 Rough endoplasmic reticulum (RER) -attachment of ribosomes to the membrane gives a rough appearance -synthesis of proteins to be secreted, sent to lysosomes or plasma membrane Eukaryotic Cell Organelles

19. 19 Smooth endoplasmic reticulum (SER) -synthesis of membrane lipids Eukaryotic Cell Organelles

20. 20 E.R. Textbook pg. 70

21. 21 Golgi apparatus -flattened stacks of membranes -packaging and distribution of materials to different parts of the cell -synthesis of cell wall components Eukaryotic Cell Organelles

22. 22 Textbook pg. 71 Protein transport: Ribosome ER Golgi apparatus Cell membrane

23. 23 Lysosomes -vesicles containing digestive enzymes -digest food, destroy worn out organelles and wastes Eukaryotic Cell Organelles

24. 24 Textbook pg. 72

25. 25 Vacuoles -membrane-bound structures There are different types of vacuoles: -central vacuole in plant cells (stores H2O) -contractile vacuoles (rid waste) -vacuoles for storage Eukaryotic Cell Organelles

26. 26 Mitochondria – Site of Cell Respiration -contain enzymes for creating ATP (energy) -contain their own DNA Eukaryotic Cell Organelles

27. 27 Mitochondria Textbook pg. 74

28. 28 Chloroplasts -organelles present in green cells -contain chlorophyll for photosynthesis -double membrane -chlorophyll contained in thylakoids/grana Eukaryotic Cell Organelles

29. 29 Chloroplasts Textbook pg. 75

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31. 31 Chromoplast -organelles present in some Plant cells -contain color Pigments (Orange - Yellow - Red) - Fruits/Veggies – Fall Leaves

32. 32 Leucoplast - Colorless organelles present in Plant cells -Food storage – e.g. “Starch” in potato cells

33. 33 Cytoskeleton -network of protein fibers -supports the shape of the cell -keeps organelles in fixed locations -helps move materials within the cell

34. 34 Cytoskeleton Textbook pg. 77

35. 35 Extracellular Structures Cell walls -present surrounding the cells of plants, fungi, Bacteria, and some protists -plant and protist cell walls - cellulose -fungal cell walls - chitin

36. 36 Textbook pg. 79 & 82

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