Cellular Organization & Reproduction


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Cellular Organization & Reproduction

  1. 1. Junhel C. Dalanon, DDM, MAT
  2. 2. <ul><ul><li>Zacharias Janssen – studied the cells using an improvised microscope </li></ul></ul><ul><ul><li>Robert Hooke </li></ul></ul><ul><ul><ul><li>made most important observation on cells (thin slice of cork from oak tree) </li></ul></ul></ul><ul><ul><ul><li>“ cells” – small rooms he saw on the empty chambers </li></ul></ul></ul><ul><ul><ul><li>Micrographia (1665) – his findings are published in this book; established the knowledge of cell structure on a firm basis </li></ul></ul></ul><ul><ul><li>Anton van Leeuwenhoek – devised a simple microscope (200x magnification) </li></ul></ul><ul><ul><li>Johannes Evangelista Purkinje </li></ul></ul><ul><ul><ul><li>cell is not empty but contains gelatinous fluid </li></ul></ul></ul><ul><ul><ul><li>named the fluid “protoplasm” </li></ul></ul></ul><ul><ul><li>Matthias Jakob Schleiden – plants are made up of cells </li></ul></ul><ul><ul><li>Theodore Schwann – both plants and animals are made of cells </li></ul></ul><ul><ul><li>Rudolf Ludwig Karl Virchow – all living things are made up of cells </li></ul></ul>
  3. 3. Zaccharias Janssen
  4. 4. Robert Hooke
  5. 5. Anton van Leeuwenhoek
  6. 6. Johannes Evangelista Purkinje
  7. 7. Matthias Jakob Schleiden
  8. 8. Theodore Schwann
  9. 9. Rudolf Ludwig Karl Virchow
  10. 10. Tools for Biological Research The Microscope
  11. 11. <ul><ul><li>Hold it by the arm with one hand </li></ul></ul><ul><ul><li>The other hand should be under the base </li></ul></ul><ul><ul><li>Wipe it clean using a tissue paper or muslin cloth </li></ul></ul><ul><ul><li>Lens paper may be used for cleaning the lenses </li></ul></ul>
  12. 12. <ul><ul><li>Place the microscope about an inch from the edge of the table. </li></ul></ul><ul><ul><li>Position the lower power objective (LPO) above the center of the stage. </li></ul></ul><ul><ul><li>Adjust the iris diaphragm by getting the biggest opening. </li></ul></ul><ul><ul><li>If there is a condenser just below the center of the stage, move it until it is in its uppermost position. </li></ul></ul><ul><ul><li>Adjust the mirror to get the right illumination. </li></ul></ul><ul><ul><li>When starting to focus, see to it that the left eye is before the ocular lens or eyepiece. </li></ul></ul><ul><ul><li>Adjust the mirror until a bright illumination is seen. </li></ul></ul><ul><ul><li>Place the slide with specimen beneath the LPO to HPO . </li></ul></ul>
  13. 13. The Compound Microscope
  14. 14. <ul><ul><li>MAIN PARTS </li></ul></ul><ul><ul><ul><li>Magnifying Parts – used to enlarge the view of specimens </li></ul></ul></ul><ul><ul><ul><ul><li>Ocular Lens </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Objective Lens </li></ul></ul></ul></ul><ul><ul><ul><li>Illuminating Parts –used to supply light to the slide on the stage </li></ul></ul></ul><ul><ul><ul><ul><li>Mirror </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Condenser </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Iris Diaphragm </li></ul></ul></ul></ul><ul><ul><ul><li>Mechanical Parts – used to support and move parts of the microscope </li></ul></ul></ul><ul><ul><ul><ul><li>Fine Adjustment Knob </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Coarse Adjustment Knob </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Others </li></ul></ul></ul></ul>
  15. 15. <ul><ul><li>Specific Parts </li></ul></ul><ul><ul><ul><li>Ocular Lens (Eyepiece) – magnifies the image formed by the objectives; 5x or 10x magnification </li></ul></ul></ul><ul><ul><ul><li>Objective Lens – most important optical part </li></ul></ul></ul><ul><ul><ul><ul><li>Low Power Objective (LPO) </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Shorter </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>10x </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Locates and shows structure of specimen </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><li>High Power Objective (HPO) </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Long & slender </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>45x or 60x </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Shows detailed structure </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><li>Oil Immersion Objective </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Long or short </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>99x or 100x </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Increase the resolution of the microscope </li></ul></ul></ul></ul></ul><ul><ul><ul><li>Mirror – collects & reflects light to microscope </li></ul></ul></ul><ul><ul><ul><li>Condenser – condenses to direct maximum light to an object </li></ul></ul></ul><ul><ul><ul><li>Iris Diaphragm – controls the entrance of light </li></ul></ul></ul>
  16. 16. <ul><ul><ul><li>Stage – holds the slide with the specimen </li></ul></ul></ul><ul><ul><ul><li>Adjustment Knobs – brings object into focus </li></ul></ul></ul><ul><ul><ul><ul><li>Coarse Adjustment Knob – focus at 10x (LPO) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Fine Adjustment Knob – focus at 40x or 60x (HPO) </li></ul></ul></ul></ul><ul><ul><ul><li>Draw Tube – houses the ocular lens and connected to the body tube </li></ul></ul></ul><ul><ul><ul><li>Body Tube – holds the draw tube; connects eyepiece to draw tube </li></ul></ul></ul><ul><ul><ul><li>Revolving Nosepiece – part where objectives are attached </li></ul></ul></ul><ul><ul><ul><li>Dust Shield – protects objectives from dust </li></ul></ul></ul><ul><ul><ul><li>Base – anchors microscope firmly on table </li></ul></ul></ul><ul><ul><ul><li>Pillar – supports upper parts of microscope </li></ul></ul></ul><ul><ul><ul><li>Inclination Joint – allows upper part of microscope to be bent </li></ul></ul></ul><ul><ul><ul><li>Lever – regulated iris diaphragm </li></ul></ul></ul>
  17. 17. Kinds of Cell Prokaryote & Eukaryote
  18. 18. <ul><ul><li>bacteria, archaea, or archaeabacteria </li></ul></ul><ul><ul><li>1-10 μ m (micrometer or microns) </li></ul></ul><ul><ul><li>have fewer structures </li></ul></ul><ul><ul><li>no true nucleus </li></ul></ul><ul><ul><li>no membrane bound organelles </li></ul></ul><ul><ul><li>no mitochondria </li></ul></ul><ul><ul><li>no golgi apparatus </li></ul></ul><ul><ul><li>no endoplasmic reticulum </li></ul></ul><ul><ul><li>Cell wall contains muramic acid </li></ul></ul><ul><ul><li>Cell wall of bacteria contains peptidoglycan </li></ul></ul><ul><ul><li>nucleoid - DNA is single circular double helix located in the region of cytosol </li></ul></ul><ul><ul><li>3 main parts: </li></ul></ul><ul><ul><ul><li>Appendages / Locomotory Structures (flagella & pili) </li></ul></ul></ul><ul><ul><ul><li>Cell Enevelope (cell wall & membrane) </li></ul></ul></ul><ul><ul><ul><li>Cytoplasm </li></ul></ul></ul>
  19. 19. Prokaryote
  20. 20. <ul><ul><li>Present in higher forms of organisms </li></ul></ul><ul><ul><li>Protists, plants, fungi, animals </li></ul></ul><ul><ul><li>Larger in size </li></ul></ul><ul><ul><li>Have membrane-bound nucleus and organelles </li></ul></ul><ul><ul><li>May be single celled, colonial, or multicellular </li></ul></ul><ul><ul><li>More chromosomes </li></ul></ul><ul><ul><li>Cell walls have cellulose </li></ul></ul>
  21. 21. Eukaryote
  22. 22. Differences Unicellular vs. Multicellular Organisms
  23. 23. <ul><ul><li>Single celled </li></ul></ul><ul><ul><li>Can function & perform independently </li></ul></ul><ul><ul><li>Can be eukaryote or prokaryote </li></ul></ul><ul><ul><li>Each cells present performs a specific function </li></ul></ul><ul><ul><li>Cells work together for entire organism </li></ul></ul><ul><ul><li>Consists of numerous cells </li></ul></ul><ul><ul><li>Cells have many membrane system </li></ul></ul>
  24. 24. Cell Parts & Function
  25. 25. Basic Cell Cell Wall / Cell Membrane Cytoplasm Nucleus Protoplasm Inclusions
  26. 26. <ul><ul><ul><li>Cell Wall & Cell Membrane </li></ul></ul></ul><ul><ul><ul><li>Protoplasm </li></ul></ul></ul><ul><ul><ul><ul><li>Nucleus </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Cytoplasm </li></ul></ul></ul></ul><ul><ul><ul><li>Inclusions </li></ul></ul></ul>
  27. 27. Animal Cell
  28. 28. Plant Cell
  29. 29. Bacteria Cell
  30. 30. <ul><ul><ul><li>Cell Wall </li></ul></ul></ul><ul><ul><ul><ul><li>present in plant cells but not in animal cells </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Rigid wall </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Serves as framework </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Provides protection to cell </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Made up of non-living substance </li></ul></ul></ul></ul><ul><ul><ul><li>Mitochondria (Chondriosomes) </li></ul></ul></ul><ul><ul><ul><ul><li>Rod-shaped or spherical </li></ul></ul></ul></ul><ul><ul><ul><ul><li>For cellular respiration </li></ul></ul></ul></ul><ul><ul><ul><ul><li>For ATP (adenosine triposphate) production </li></ul></ul></ul></ul><ul><ul><ul><li>Endoplasmic Reticulum </li></ul></ul></ul><ul><ul><ul><ul><li>Series of tubules </li></ul></ul></ul></ul><ul><ul><ul><ul><li>For transport of substances </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Site for lipid and protein synthesis </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Types: </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Smooth ER – no ribosomes attached </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Rough ER – with ribosomes attached </li></ul></ul></ul></ul></ul>
  31. 31. <ul><ul><ul><li>Microbodies </li></ul></ul></ul><ul><ul><ul><ul><li>Peroxisomes – oxidative enzymes that catalyze the removal of amino acids </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Glyoxysomes – oxidative enzymes that catalyze the removal of amino acids </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Lysosomes – made up of digestive enzymes </li></ul></ul></ul></ul><ul><ul><ul><li>Golgi Apparatus </li></ul></ul></ul><ul><ul><ul><ul><li>Consists of membrane-delimited vesicles arranged parallel </li></ul></ul></ul></ul><ul><ul><ul><li>Centrioles </li></ul></ul></ul><ul><ul><ul><ul><li>Small, dark bodies in animal cells </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Play important role in mitosis </li></ul></ul></ul></ul><ul><ul><ul><li>Vacuole </li></ul></ul></ul><ul><ul><ul><ul><li>Membrane enclosed, fluid filled space </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Consists of crystals, inorganic salts, sugars </li></ul></ul></ul></ul><ul><ul><ul><li>Nucleus </li></ul></ul></ul><ul><ul><ul><ul><li>Control center of the cell </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Easily stained </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Consists of chromosomes (for cell reproduction & heredity transmission) </li></ul></ul></ul></ul>
  32. 32. <ul><ul><ul><li>Nucleolus </li></ul></ul></ul><ul><ul><ul><ul><li>Round structure in nucleus with minute fibers & granules </li></ul></ul></ul></ul><ul><ul><ul><ul><li>For ribosomal formation </li></ul></ul></ul></ul><ul><ul><ul><li>Nuclear Sap </li></ul></ul></ul><ul><ul><ul><ul><li>Liquid matrix in nucleus </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Makes possible for chemical reaction to take place </li></ul></ul></ul></ul><ul><ul><ul><li>Cytoplasm </li></ul></ul></ul><ul><ul><ul><ul><li>Gel-like or viscous solution </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Where organelles are suspended </li></ul></ul></ul></ul><ul><ul><ul><li>Plastids </li></ul></ul></ul><ul><ul><ul><ul><li>Large membrane bound organelles </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Found in cytoplasm of plant cells </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Types: </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Chromoplast – consists of chloroplast, chlorophyll a, chlorophyll b, carotenes, and xantophyll </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Leucoplast – colorless plastid; center of starch grain formation </li></ul></ul></ul></ul></ul><ul><ul><ul><li>Ribosomes </li></ul></ul></ul><ul><ul><ul><ul><li>Actual sites of protein synthesis </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Attached to ER or suspended in cytoplasm </li></ul></ul></ul></ul>
  33. 33. <ul><ul><ul><li>Cytoskeleton </li></ul></ul></ul><ul><ul><ul><ul><li>Responsible for cell movement </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Provides shape and structural support to cell </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Gives cell proper spatial relationship </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Made up of: </li></ul></ul></ul></ul><ul><ul><ul><ul><li>- microfilaments </li></ul></ul></ul></ul><ul><ul><ul><ul><li>- microtubules </li></ul></ul></ul></ul><ul><ul><ul><ul><li>- intermediate filaments </li></ul></ul></ul></ul><ul><ul><ul><li>Glycocalyx </li></ul></ul></ul><ul><ul><ul><ul><li>Made up of: </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Attaches one cell to another </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Attaches one cell to external structures </li></ul></ul></ul></ul><ul><ul><ul><li>Plasmodesmata </li></ul></ul></ul><ul><ul><ul><ul><li>Made up of strands of protoplasm </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Connects two adjacent plant cells </li></ul></ul></ul></ul><ul><ul><ul><li>Desmosomes </li></ul></ul></ul><ul><ul><ul><ul><li>Button-like structures between two plasma membranes </li></ul></ul></ul></ul>
  34. 34. <ul><ul><ul><li>Nutrition </li></ul></ul></ul><ul><ul><ul><ul><li>Means by which organisms obtain food </li></ul></ul></ul></ul><ul><ul><ul><li>Digestion </li></ul></ul></ul><ul><ul><ul><ul><li>Breaking down complex substances into smaller & soluble form </li></ul></ul></ul></ul><ul><ul><ul><li>Absorption </li></ul></ul></ul><ul><ul><ul><ul><li>All needed materials are carried into or absorbed by the cells </li></ul></ul></ul></ul><ul><ul><ul><li>Respiration </li></ul></ul></ul><ul><ul><ul><ul><li>Gas exchange between cells & environment </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Aerobic or Anaerobic </li></ul></ul></ul></ul><ul><ul><ul><li>Excretion </li></ul></ul></ul><ul><ul><ul><ul><li>Discharging waste materials from cell to environment </li></ul></ul></ul></ul><ul><ul><ul><li>Reproduction </li></ul></ul></ul><ul><ul><ul><ul><li>Cell division resulting to increase number of cells or organisms </li></ul></ul></ul></ul>
  35. 35. <ul><ul><ul><li>Secretion </li></ul></ul></ul><ul><ul><ul><ul><li>Cell produces vitamins & hormones </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Discharges synthesized molecules </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Complex molecules of Carbohydrates, Fats, and Proteins are synthesized </li></ul></ul></ul></ul><ul><ul><ul><li>Egestion </li></ul></ul></ul><ul><ul><ul><ul><li>Elimination of food eaten or digested </li></ul></ul></ul></ul><ul><ul><ul><li>Movement </li></ul></ul></ul><ul><ul><ul><ul><li>Flow of cell content </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Locomotion </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Cellular Contraction </li></ul></ul></ul></ul><ul><ul><ul><li>Irritability </li></ul></ul></ul><ul><ul><ul><ul><li>Reaction to stimuli </li></ul></ul></ul></ul>
  36. 36. <ul><ul><ul><li>Diffusion </li></ul></ul></ul><ul><ul><ul><ul><li>Substance is spread throughout space from area of greater concentration to lesser </li></ul></ul></ul></ul><ul><ul><ul><ul><li>From greater diffusion pressure to lesser pressure </li></ul></ul></ul></ul><ul><ul><ul><li>Osmosis </li></ul></ul></ul><ul><ul><ul><ul><li>A form of diffusion involving water </li></ul></ul></ul></ul><ul><ul><ul><li>Turgidity </li></ul></ul></ul><ul><ul><ul><ul><li>All needed materials are carried into or absorbed by the cells </li></ul></ul></ul></ul><ul><ul><ul><li>Plasmolysis </li></ul></ul></ul><ul><ul><ul><ul><li>Shrinkage of cells caused by diffusion of water into environment due to exposure to solution with high osmotic pressure </li></ul></ul></ul></ul><ul><ul><ul><li>Filtration </li></ul></ul></ul><ul><ul><ul><ul><li>Separating materials from liquid mixture through a membrane filter </li></ul></ul></ul></ul><ul><ul><ul><li>Passive Transport </li></ul></ul></ul><ul><ul><ul><ul><li>Does not use chemical energy in transporting materials </li></ul></ul></ul></ul>
  37. 37. Diffusion
  38. 38. Osmosis
  39. 39. Turgidity
  40. 40. Plasmolysis
  41. 41. Filtration
  42. 42. Passive Transport
  43. 43. Passive Transport <ul><li>Transport by simple diffusion </li></ul><ul><li>Facilitated diffusion: carrier proteins and ion channels </li></ul><ul><li>Osmosis and hydrostatic pressure </li></ul>Active Transport <ul><li>Active Transport </li></ul><ul><li>Exocytosis </li></ul><ul><li>Endocytosis </li></ul><ul><li>Phagocytosis </li></ul><ul><li>Pinocytosis </li></ul>
  44. 44. Cell Reproduction Cell Cycle
  45. 45. The Cell Cycle <ul><li>The sequence of growth and division of a cell. </li></ul><ul><li>95% of cell cycle in interphase </li></ul><ul><li>5% of cell cycle in mitosis </li></ul>
  46. 46. Interphase <ul><li>Growth Stage 1 (G 1 ) – metabolic activity of the cell </li></ul><ul><li>Synthesis Stage (S) – metabolic activity of the cell, replication of DNA </li></ul><ul><li>Growth Stage 2 (G 2 ) – metabolic activity of the cell, prepare for division </li></ul><ul><li>M-Phase – Mitosis and Meiosis </li></ul>
  47. 47. Cell Reproduction Mitosis & Meiosis
  48. 48. Where is all the genetic information found in a cell? <ul><li>On the genes on the Chromosomes </li></ul><ul><li>Chromosomes are actually DNA and proteins </li></ul><ul><li>If cells were the size of a basketball, your DNA would stretch 64km (40 miles) </li></ul>
  49. 49. A Tale of Tall DNA <ul><li>If you unraveled all your chromosomes from all of your cells and laid out the DNA end to end, the strands would stretch from the Earth to the Moon about 6,000 times . </li></ul>
  50. 50. Prokaryotes They have to be different!!! <ul><li>Usually, only have 1 chromosome in a circular pattern called a Plasmid </li></ul>
  51. 51. <ul><li>Chromosome s </li></ul><ul><li>Before coiling, DNA & proteins w/in nucleus are called Chromatin </li></ul><ul><li>DNA coils around a protein histone (spool) </li></ul><ul><li>Coiling continues w/ supercoiling </li></ul><ul><li>Structure shortens up Chromosome </li></ul><ul><li>DNA copies itself & are called chromatids & are held together by a centromere </li></ul>Chromosome Structure Chromatid Double Chromosome
  52. 52. How many chromosomes do we have? <ul><li>Chromosome number: (# of Chromosomes in a body cell ) – Diploid (2N) number </li></ul><ul><li>Specific for each species of organisms </li></ul><ul><li>Human – 46 Fruit fly - 8 </li></ul><ul><li>Chimpanzee – 48 Mosquito - 6 </li></ul><ul><li>Gorilla – 48 King Crab - 208 </li></ul><ul><li>Horse – 64 Potato - 48 </li></ul><ul><li>Donkey - 62 Bat - 44 </li></ul>
  53. 53. Types of Chromosomes <ul><li>Autosomes </li></ul><ul><ul><ul><li>body chromosomes – </li></ul></ul></ul><ul><ul><ul><li>22 pairs in us </li></ul></ul></ul><ul><li>Sex chromosomes </li></ul><ul><ul><ul><li>X or Y chromosomes – </li></ul></ul></ul><ul><ul><ul><li>We should have 2 </li></ul></ul></ul>
  54. 54. Chromosome Number <ul><li>Diploid (2N) number – 2 of every chromosome – found in body cells </li></ul><ul><li>1 set came from each of your parents – 23 pairs for the 2 sets </li></ul><ul><li> 2 identical chromosomes are called homologous chromosomes </li></ul><ul><li>Haploid (1N) number – 1 set of chromosomes per sex cell </li></ul>
  55. 55. Karyotypes <ul><li>Shows individual’s chromosomes during cell division </li></ul><ul><li>Males have 44 autosomes and 1 unmatched set of sex chromosomes – XY </li></ul><ul><li> Females have all 23 pairs matching – XX sex chromosomes </li></ul>
  56. 56. Why do cells make copies of themselves, instead of just getting larger? <ul><li>Need cell differentiation to be more efficient </li></ul><ul><li>Information crisis – DNA can not get message to entire cell. </li></ul><ul><li>Transport in, out and throughout cell is difficult – Surface area: Volume ratio is too small. </li></ul>
  57. 57. Prokaryotic organisms and unicellular organisms <ul><li>Reproduce asexually by binary fission </li></ul><ul><li>DNA makes a copy (attach to plasma membrane) </li></ul><ul><li>Cell makes a new nucleus </li></ul><ul><li>Cell divides up contents of cell </li></ul><ul><li>2 identical cells result when wall forms between the 2 cells </li></ul><ul><li>Binary fission </li></ul>
  58. 58. Cell Division in Eukaryotic cells <ul><li>Mitosis – production of 2 identical 2N nuclei. </li></ul><ul><li>Involved with body cells </li></ul><ul><li>Meiosis – production of 1N sex cells </li></ul>
  59. 59. http://biotech-adventure.okstate.edu/low/basics/mitosis/mitosis-diagram/diagram.gif
  60. 60. Cell Cycle
  61. 61. Mitosis <ul><li>One type of cell division </li></ul>Cell process in which the nucleus divides to form two nuclei identical to each other, and identical to the original nucleus, in a series of steps (prophase, metaphase, anaphase, and telophase)
  62. 62. Mitosis allows for growth and replaces worn out or damaged cells.
  63. 63. Interphase <ul><li>Period of growth & development </li></ul><ul><li>Hereditary information (DNA) copied (replicated / duplicated) </li></ul><ul><li>Cells that do not divide (nerves) are always in interphase </li></ul>
  64. 65. Prophase <ul><li>DNA begins to shorten & thicken </li></ul><ul><ul><li>Now called chromatids / chromosomes </li></ul></ul><ul><li>Centromeres form </li></ul><ul><li>Nuclear membrane breaks apart </li></ul><ul><li>Spindle fibers form </li></ul>
  65. 67. Metaphase <ul><li>Chromatids / chromosomes line up </li></ul><ul><li>Centromere attaches to spindle fibers </li></ul>
  66. 69. Anaphase <ul><li>Centromeres divide </li></ul><ul><li>Spindle fibers shorten </li></ul><ul><li>Chromatid pairs separate – move to ends of cell </li></ul><ul><li>Chromatids are now called </li></ul><ul><ul><li>Each ½ of the pair is now called a chromosome </li></ul></ul>
  67. 71. Telophase <ul><li>Spindle fibers disappear </li></ul><ul><li>Chromosomes uncoil </li></ul><ul><li>Nuclear membrane forms </li></ul><ul><li>Cell divides (cytokinesis) </li></ul>
  68. 73. Interphase                                                               Prophase                                                               Metaphase                                                               Anaphase                                                               Telophase                                                               Interphase                                                              
  69. 74. Results of Mitosis <ul><li>Division of nucleus </li></ul><ul><ul><li>Nuclei are identical to each other </li></ul></ul><ul><ul><ul><li>Same number & type of chromosomes </li></ul></ul></ul>
  70. 75. Asexual Reproduction A type of reproduction - fission, budding, and regeneration - in which a new organism is produced from one parent and has DNA identical to the parent organism.
  71. 76. Asexual Reproduction <ul><li>Offspring produced from one organism </li></ul><ul><li>Hereditary information is identical </li></ul><ul><li>Mitosis is one form of asexual reproduction </li></ul>
  72. 77. Sexual Reproduction Meiosis
  73. 78. Sexual Reproduction A type of reproduction in which two sex cells, usually an egg and a sperm, join to form a zygote, which will develop into a new organism with a unique identity.
  74. 79. Sexual reproduction results in a great variety, or diversity, of offspring.
  75. 80. Meiosis <ul><li>The nucleus divides twice </li></ul><ul><ul><li>Meiosis I </li></ul></ul><ul><ul><li>Meiosis II </li></ul></ul>
  76. 82. Interphase <ul><li>DNA is duplicated </li></ul>
  77. 83. Prophase I <ul><li>DNA shorten & thicken </li></ul><ul><ul><li>Forms chromatids / chromosomes </li></ul></ul>
  78. 85. Metaphase I <ul><li>Copied chromatids / chromosomes line up in middle of cell </li></ul><ul><li>Centromeres attach to spindle fibers </li></ul>
  79. 87. Anaphase I <ul><li>Chromatid pairs are pulled apart </li></ul><ul><ul><li>They DO NOT separate </li></ul></ul><ul><li>Move to ends of cell </li></ul>
  80. 89. Telophase I <ul><li>Cell divides </li></ul><ul><li>No further replication of hereditary material </li></ul>
  81. 91. There are now two cells. Both cells have full sets of genetic material (chromosomes)
  82. 92. Prophase II <ul><li>Similar to mitosis </li></ul><ul><ul><li>Starts with TWO cells instead of one </li></ul></ul><ul><ul><ul><li>Spindle fibers appear </li></ul></ul></ul>
  83. 94. Metaphase II <ul><li>Duplicated chromatid / chromosomes line up in middle of cell </li></ul><ul><li>Spindle fibers attach to centromeres </li></ul>
  84. 96. Anaphase II <ul><li>Centromere divides </li></ul><ul><ul><li>Chromatids separate & move to ends of cell </li></ul></ul><ul><ul><ul><li>Chromatids are now individual chromosomes </li></ul></ul></ul>
  85. 98. Telophase II <ul><li>Spindle fibers disappear </li></ul><ul><li>Nuclear membranes form at each end of cell </li></ul><ul><li>Cells divide </li></ul><ul><ul><li>Results in 4 cells </li></ul></ul><ul><ul><ul><li>Each with ½ the original number of chromosomes </li></ul></ul></ul>
  86. 100. In summary: Meiosis <ul><li>Two cells form during meiosis I </li></ul><ul><li>In meiosis II, both of these cells form two cells </li></ul><ul><li>The two divisions of the nucleus result in four sex cells (gametes) </li></ul><ul><li>Each has one-half the number of chromosomes in its nucleus that was in the original nucleus </li></ul>