1. The Cell & Mitosis

2. The Cell: Fundamental Unit of Life Life as we define it consists of cells All cells arise from previously existing cells Organisms depend upon the activity of cells to exist Subcellular structures are responsible for specific cellular biochemical functions according to the “complimentarity of structure & function” Rudolf Virchow says:

3. This is Modern Cell Theory! There are TRILLIONS of cells in your body Approximately 200 distinct types They range in size from about 2 micrometers (sperm) to over a meter (motor neurons)

4. Anatomy of a Typical Animal Cell

5. Organelle Functions

7. The Plasma Membrane

8. Functions of membrane proteins

9. More functions of membrane proteins

10. Subcellular organelles and other subcellular structures Cytosol – the fluid portion of the cytoplasm Cytoplasm – cytosol + subcellular organelles Many organelles are bound by their own phospholipid membranes All have their own unique functions

11. The Cytoskeleton

12. Microvilli Increase surface area for absorption Attach to cytoskeleton

13. Centrioles

14. Cilia

15. Fig. 03.19 Ribosomes

16. Endoplasmic reticulum

17. Golgi apparatus

18. Transport Vesicles Figure 3–7a Carry materials to and from Golgi apparatus

20. Lysosomes

21. Mitochondria: Powerhouse of the Cell

22. Mitochondrial Function Mitochondrion takes chemical energy from food (glucose): –produces energy molecule ATP

23. The Reactions glucose + oxygen + ADP  carbon dioxide + water + ATP Glycolysis: –glucose to pyruvic acid (in cytosol) Tricarboxylic acid cycle (TCA cycle): – pyruvic acid to CO 2 (in matrix) The TCA cycle is more commonly known as “Krebs Cycle” or the Citric acid cycle

24. The Nucleus

25. Structure of the Nucleus Nucleus: –largest organelle Nuclear envelope: –double membrane around the nucleus Perinuclear space: –between 2 layers of nuclear envelope Nuclear pores: –communication passages

26. DNA: Blueprint of Life

27. Protein Synthesis Transcription: –copies instructions from DNA to mRNA (in nucleus) Translation: –ribosome reads code from mRNA (in cytoplasm) –assembles amino acids into polypeptide chain

28. To produce a protein the DNA must be “transcribed” into mRNA

29. Translation mRNA moves: –from the nucleus –through a nuclear pore Figure 3–13

30. Translation (2) mRNA moves: –to a ribosome in cytoplasm –surrounded by amino acids

31. Translation (3) mRNA binds to ribosomal subunits tRNA delivers amino acids to mRNA

32. Translation (4) tRNA anticodon binds to mRNA codon 1 mRNA codon translates to 1 amino acid

33. Translation (5) Enzymes join amino acids with peptide bonds Polypeptide chain has specific sequence of amino acids

34. Translation (6) At stop codon, components separate

35. Translation summary

36. 3 letter “words” called codons code for amino acids

37. Summary of protein synthesis

38. Membrane permeability An important function of the membrane is to control what can enter or leave the cell How easily something passes through is called “permeability” If something cannot pass through the membrane is said to be “impermeable”

39. Gradients The differential concentrations of substances leads to the establishment of gradients According to the 2 nd LTD, things tend to move from a high concentration to a low concentration. If there is a gradient across a membrane, particles will want to flow across that membrane

40. Gradients can be of concentrations solutes or charged particles such as ions. Ion gradients are called electrical gradients

41. Types of transport Passive –Simple diffusion –Facilitated or protein mediated –Filtration –Osmosis Active –ATP driven solute pumps –Vesicular Endocytosis –Phagocytosis –Bulk-phase endocytocysis (pinocytosis) Exocytosis

42. Cell transport mechanisms

43. Diffusion and the Cell Membrane Diffusion can be simple or channel-mediated

44. Simple Diffusion Materials which diffuse through cell membrane: –lipid-soluble compounds (alcohols, fatty acids, and steroids) –dissolved gases (oxygen and carbon dioxide)

45. Channel-Mediated Diffusion Materials which pass through transmembrane proteins (channels): –are water soluble compounds –are ions

46. Facilitated Diffusion Passive Carrier mediated

47. Fig. 03.09 Gated ion channels control permeability

48. Fig. 03.10 Facilitated diffusion: it’s passive and controls permeability

49. Diffusion rate influences Slope of concentration gradient Temperature Molecular or atomic weight of solute Density of solvent Surface area Diffusion distance

50. Factors in Channel-Mediated Diffusion Passage depends on: –size –charge –interaction with the channel

51. Osmosis Osmosis is the diffusion of water across the cell membrane

52. Tonicity Isotonic – same concentration of solute inside of the cell as outside. No net movement of water Hypotonic – lower concentration of solute outside than in. Water move into cell (causes lysis). Hypertonic – higher concentration of solute outside of cell than inside. Watre moves out of cell (causes crenation).

53. Effect of tonicity on red blood cells

54. Active Transport It requires expenditure of cellular energy Usually involves ATP Can be primary or secondary Includes pumps & bulk phase or vesicular mechanisms

55. Sodium- Potassium Exchange Pump

56. Fig. 03.11 The sodium/potassium pump: an antiport system

57. Secondary Active Transport Na + concentration gradient drives glucose transport ATP energy pumps Na + back out

58. Vesicular transport Endocytosis – taking things in. –Receptor mediated –Phagocytosis –Pinocytosis Exocytosis – secreting things.

59. Fig. 03.13 Receptor mediated endocytosis

60. Pinocytosis: cellular drinking

61. Phagocytosis Phagocytosis (cell eating) –pseudopodia (psuedo = false, podia = feet) –engulf large objects in phagosomes

62. Exocytosis Ejects secretory products and wastes

63. Electrical Charge Inside cell membrane is slightly negative, outside is slightly positive Unequal charge across the cell membrane is transmembrane potential Resting potential ranges from —10 mV to —100 mV, depending on cell type

64. Mitosis Every cell in your body arises from the process of mitosis Before a cell can reproduce itself, it must first replicate its DNA

65. Fig. 03.31

66. DNA Replication DNA strands unwind DNA polymerase attaches complementary nucleotides

67. Fig. 03.32 DNA is replicated in a semiconservative pattern

68. Then the cell goes through the following stages Prophase Metaphase Anaphase Telophase Cytokinesis

69. Prophase

70. Late prophase

71. Metaphase

72. Anaphase

73. Telophase: defined by the presence of a cleavage furrow & Cytokinesis

74. Fig. 03.33

75. Chemicals Controlling Cell Division

76. Cancer

77. Fig. 03.34 Cells can be highly specialized. The structural specializations reflect their function!

78. SUMMARY (1 of 4) Structures and functions of human cells Structures and functions of membranous and nonmembranous organelles

79. SUMMARY (2 of 4) ATP, mitochondria, and the process of aerobic cellular respiration Structures and functions of the nucleus: –control functions of nucleic acids –structures and replication of DNA –DNA and RNA in protein synthesis

80. SUMMARY (3 of 4) Structures and chemical activities of the cell membrane: –diffusion and osmosis –active transport proteins –vesicles in endocytosis and exocytosis –electrical properties of plasma membrane

81. SUMMARY (4 of 4) Stages and processes of cell division: –DNA replication –mitosis –cytokinesis Links between cell division, energy use, and cancer

82. Next, Tissues