Cell Reproduction

• Viruses


  Replicate through simple structures: protein coat and nucleic acid
• Prokaryotes


  Reproduce by simple division
• Eukaryotes


  Reproduce through a cell cycle
• Cell cycle


  1. Interphase: G1 = cell grows, duplication of organelles, S = synthesis of DNA, G2 = finish the duplication of cellular organelles

  2. Mitosis = nuclear and cellular division

  3. Cytokinesis = division of cytoplasm into two new daughter cells
• G1/S Checkpoint


  Checks cell size, damage, nutrient availability, will undergo apoptosis if no suitable
• G2/M Checkpoint


  Checks cell size, damage, error, may pause for repair
• Mitosis


  1. Prophase- chromosomes condense and spindle fibers form

  2. Prometaphase: nuclear membrane disintegrates and spindle fibers attach

  3. Metaphase: chromosomes line up

  4. Anaphase: sister chromatids separate

  5. Telophase: chromosomes arrive at poles and membrane reforms
• Meiosis


  1. Prophase I: chromosomes condense, homologous pairs are made, crossing over takes place

  2. Metaphase I: pairs line up

  3. Anaphase I: pairs move towards poles

  4. Telophase I: pairs arrive at poles and cytoplasm divides

  5. Prophase II- chromosomes recondense

  6. Metaphase II: chromosomes line up

  7. Anaphase II: separate into sister chromatids

  8. Telophase II: chromosomes arrive at poles and cytoplasm divides