1. Chapter 6 A Tour of the Cell

2. Types of Cells u Prokaryotic (bacteria) - lack a nucleus and other membrane bounded structures (simple) u Eukaryotic (plant and animal) - have a nucleus and other membrane bounded structures (more complex)

3. ProkaryoticEukaryotic Nucleus

4. Prokaryotic Eukaryotic

5. Why Are Cells So Small? u Cell volume to surface area ratios favor small size. u Nucleus to cytoplasm consideration (control). u Metabolic requirements.

7. Basic Eukaryotic Cell Organization u Membrane u Nucleus u Cytoplasm u Organelles

8. Animal Cell

9. Plant Cell

10. Plasma Membrane u Separates the cell from the environment. u Regulates the movement of materials in/out of a cell.

12. Cytoplasm u Cell substance between the cell membrane and the nucleus. u The “fluid” part of a cell. u Contains all organelles

14. Organelle u Term means "small organ” u Structure in a cell with a specialized function.

15. Nucleus u Contains genetic material (DNA) u Directs all cell functions

16. Nucleus Structure u Nuclear membrane u Nuclear pores u Nucleolus u Chromatin

18. Nuclear Membrane u Double membrane making up the boundary of the nucleus

20. Nuclear Pores u Regular “holes” through both nuclear membranes. u Allows materials in/out of nucleus.

22. Nucleolus u Storage area for ribosomes.

23. Chromatin u Chrom: colored u - tin: threads u DNA and Protein in a “loose” format. Will form the cell’s chromosomes.

25. Ribosomes u Structure: 2 subunits made of protein and ribosomal RNA (rRNA) u No membrane. u Function: protein synthesis.

27. Ribosome Locations u Free in the cytoplasm - make proteins for use in cytosol. u Membrane bound (attached to a membrane) - make proteins that are exported from the cell.

28. Endomembrane System u Related membranes throughout the cell u Nuclear envelope u endoplasmic reticulum u golgi apparatus u lysosomes u vacuoles u plasma membrane

29. Endomembrane System

30. Endoplasmic Reticulum u Often referred to as the ER. u Often continuous with (connects to) the nuclear membrane.

32. Structure of ER u Folded sheets or tubes of membranes.

33. Types of ER u Smooth ER: no ribosomes. u Used for lipid synthesis, carbohydrate storage, detoxification of poisons. u Rough ER: covered with ribosomes u Makes secretory proteins.

35. Golgi Apparatus u Structure: parallel array of flattened cisternae. (looks like a stack of Pita bread) u Found close to the ER

37. Structure Has 2 Faces u Cis face - side toward the nucleus. Receiving side. face - side away from the nucleus. Shipping side. u Trans face - side away from the nucleus. Shipping side.

38. Function of Golgi Bodies u Processing - modification of ER products u Distribution - packaging of ER products for transport. u ER products packaged into vesicles and shipped out

39. Lysosome u Single membrane. u Made from the Trans face of the Golgi apparatus.

40. Lysosome Function u Breakdown and degradation of cellular materials.

43. Group Questions u Which of the following structures would be found in a prokaryotic cell? u A. Endoplasmic reticulum u B. Ribosome u C. Golgi apparatus u D. Nuclear envelope u E. Flagellum

44. Group Questions u Why are most animal cells, regardless of species, relatively small and about the same size? u A. small cells avoid excessive osmosis and subsequent lysis u B. small cells have a small surface to volume ratio u C. small cells have a large surface to volume ratio u D. small cells require less energy u E. small cells fit together more tightly

45. Group Questions u To manufacture the components of the plasma membrane, activity from all of the following are required EXCEPT: u A. lysosomes u B. rough ER u C. mRNA u D. Golgi apparatus u E. vesicles

46. Group Questions u In the inherited disorder Pompe’s disease, glycogen breakdown in the cytosol occurs normally and blood glucose levels are normal, yet glycogen accumulates in lysosomes. This suggests a malfunction with: u A. catabolic enzymes in the mitochondria u B. anabolic enzymes in the lysosomes u C. catabolic enzymes in the lysosomes u D. membrane transport during exocytosis u E. membrane transport during endocytosis

47. Group Questions u All of the following are membrane bound bodies in eukaryotic cells EXCEPT: u A. lysosome u B. mitochondrion u C. endoplasmic reticulum u D. nucleolus u E. Golgi body

48. Vacuoles u Structure - single membrane, usually larger than the Golgi vesicles. u Function - depends on the organism. u Pump out water u Store food or water

49. Plant Vacuole u Large single vacuole when mature making up to 90% of the cell's volume. u Tonoplast - the name for the vacuole membrane.

51. Peroxisomes u Similar to lysosomes, but they contain enzymes to break down hydrogen peroxide

52. Enzymes in a crystal

53. Mitochondria Structure u 2 membranes u ATP generated at inner membrane u Matrix: inner space. u Intermembrane space: area between the membranes.

55. Mitochondria Functions u Cell Respiration - the release of energy from food. u Major location of ATP generation. u “Powerhouse” of the cell.

56. Mitochondria u Have ribosomes. u Have their own DNA. u Can reproduce themselves. u May have been independent cells at one time.

57. Chloroplast Function u Photosynthesis - the use of light energy to make food.

59. Chloroplasts u Contain ribosomes. u Contain DNA. u Can reproduce themselves. u Often contain starch. u May have been independent cells at one time.

60. Cytoskeleton u Network of rods and filaments in the cytoplasm

62. Cytoskeleton Functions u Cell structure and shape. u Cell movement. u Cell division - helps build cell walls and move the chromosomes apart.

64. Cilia and Flagella u Cilia - short, but numerous. u Flagella - long, but few. u Function - to move cells or to sweep materials past a cell.

67. Centrioles u Usually one pair per cell, located close to the nucleus. u Found in animal cells. u Help in cell division.

68. Cytoskeleton u Very dynamic; changing in composition and shape frequently. u Cell is not just a "bag" of cytoplasm within a cell membrane.

69. Cell Wall u Nonliving “jacket” that surrounds some cells. u Found in: u Plants u Prokaryotes u Fungi u Some Protists

71. Cell Walls u Function as the cell's exoskeleton for support and protection.

72. Extracellular Matrix - ECM u “Fuzzy coat” on animal cells. u Helps glue cells together. u Made of glycoproteins and collagen. u Evidence suggests ECM is involved with cell behavior and cell communication.

74. Intercellular Junctions u Join neighboring cells u Plant cells u Plasmodesmata u Animal cells u Tight junctions u Desmosomes u Gap junctions

75. Plasmodesmata u Channels between cells through adjacent cell walls.

77. Intercellular Juctions u Animals: u Tight junctions u Desmosomes u Gap junctions

79. Tight Junctions u Very tight fusion of the membranes of adjacent cells. u Seals off areas between the cells. u Prevents movement of materials around cells.

81. Desmosomes u Bundles of filaments which anchor junctions between cells. u Does not close off the area between adjacent cells.

83. Gap Junctions u Open channels between cells, similar to plasmodesmata. u Allows “communication” between cells.

85. Summary u Answer: Why is Life cellular and what are the factors that affect cell size? u Be able to identify cellular parts, their structure, and their functions.