1. 1 Cell Structure Chapter 7

2. 2

3. 3 Cell Theory All organisms are composed of one or more cells. Cells are the smallest living units of all living organisms. Cells come from pre- existing cells.

4. 4 Prokaryote vs Eukaryote Cell Prokaryote – no nucleus - single loop of DNA - few organelles - bacteria Eukaryote – enclosed nucleus - DNA in chromosomes - many organelles - plants, animals

5. 5 Cell Size Most cells are relatively small because as size increases, volume increases much more rapidly. (surface area:volume) – longer diffusion time, less efficient

6. 6 Visualizing Cells Resolution - minimum distance two points can be apart and still be distinguished as two separate points – Compound microscopes - magnify in stages using multiple lenses – Transmission electron microscope - electrons transmitted through specimen – Scanning electron microscope - electrons beamed onto surface of the specimen

7. 7 Visualizing Cells

8. 8

9. 9

10. 10 Cell Organelles Cytoplasm – a jelly-like substance that supports the organelles inside cell membrane encloses the cell contents – phospholipid bilayer with embedded proteins Phospholipid Membrane proteins

11. 11 Nucleus Contains genetic material (DNA) Directs activities of the cell – Nucleolus - region of RNA synthesis (needed for making proteins in the cell) Surface of nucleus bound by two nuclear membrane – Nuclear pores – protein gatekeepers – Usually proteins go in and RNA goes out

12. 12 Nucleus

13. 13 Chromosomes DNA of eukaryotes is densely packed into chromosomes. Each chromosome contains approximately 1 metre of DNA (if stretched out) There are 46 chromosomes in EVERY cell of your body! The DNA from all of your cells in your body stretched end to end would go from the Earth to the Sun 100 times! There is approximately 0.7 kg (1 ½ lbs) of DNA in your body!

14. 14 Endoplasmic reticulum Serves as system of channels from the nucleus Rough ER is “rough” because of ribosomes attached (sites of protein synthesis) Smooth ER – lack ribosomes – contain embedded enzymes which speed up the synthesis of carbohydrate and lipid molecules

15. 15

16. 16 Electron micrograph of smooth endoplasmic reticulum Rough endoplasmic reticulum with ribosomes

17. 17 Golgi Apparatus – collection of Golgi bodies  collect, package, and distribute molecules synthesized at one location in the cell and utilized at another location

18. 18 Golgi apparatus Protein Proteins Transport vesicle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The golgi apparatus sorts and repackages molecules into vesicles that then travel to the cell membrane to be expelled

19. 19

20. 20 Lysosomes - membrane-bound vesicles containing digestive enzymes – from Golgi apparatus - The enzymes break down food particles and destroy old, worn-out cell parts

21. 21 Cytoplasm Phagocytosis Food vesicle Golgi apparatus Lysosomes Plasma membrane Digestion of phagocytized food particles or cells Endoplasmic reticulum Transport vesicle Old or damaged organelle Breakdown of old organelle Extracellular fluid Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

22. 22 Ribosomes – site of protein synthesis – assembled in nucleolus of cell

23. 23

24. 24 Mitochondria - contain 2 membranes (exterior and interior membranes) - mitochondria convert glucose to usable energy for the cell (ATP)

25. 25 Mitochondria

26. 26 Mitochondria A. "Powerhouse of the cell" - cellular metabolism B. Structure- outer and inner membranes – lots of surface are for maximum efficiency  mitochondria line the flagellum of this cell

27. 27 Chloroplasts - Chloroplasts are larger and more complex than mitochondria - they are ONLY found in plant cells - they have special pigment molecules called CHLOROPHYLL that absorb sunlight and convert it into GLUCOSE

28. 28 Cytoskeleton Network of protein fibers supporting cell shape and anchoring organelles – Actin filaments  cell movement – Microtubules  Hollow tubes  Facilitate cell movement – Intermediate filaments  Stable - don’t break down Actin Microtubules Intermediate filaments

29. 29 Cytoskeleton

30. 30 Plant Cells Central vacuole – often found in the center of a plant, and serves as a storage facility for water and other materials – It also provides some support for the cell because it is filled with water Cell wall - made of cellulose (long chains of glucose molecules)

31. 31 Plant Cell Small green chloroplasts can be seen inside each plant cell

32. 32 Plant cell

33. 33 Animal Cells Animal cells lack cell walls - these cells use a variety of proteins to provide support, strength, and resilience

34. 34 Animal cells The centriole - is found only in animal cells - it is located outside the nucleus and plays a role in cell division

35. 35 The centriole is cylindrical and attaches spindle fibres to help pull chromosomes apart during cell division Electron micrograph of 2 centrioles inside a cell

36. 36

37. 37 CELLS Watch the following video clip and try to identify the organelles inside the cell!

38. 38

39. 39 The Harvard Cell http://multimedia.mcb.harvard.edu/

40. 40 What type of cell is this? cork cells

41. 41 pollen grains

42. 42 bone cells – growth plate

43. 43 onion cells

44. 44 human red blood cells

45. 45 bacteria

46. 46 brain cells

47. 47 Neuromuscular junction – where nerve cells connect with muscle cells

48. 48 moss cells

49. 49 Sperm and egg - conception

50. 50 blood clot

51. 51 Hair cells in inner ear

52. 52 rods and cones – cells of retina

53. 53 tooth plaque – bacteria + food particles

54. 54 basal cell carcinoma – skin cancer

55. 55 brain cells

56. 56 normal red blood cell ---------- sickled red blood cell

57. 57 common cold virus

58. 58 human immunodeficiency virus (HIV)

59. 59 H1N1 virus (swine flu)