Cell cycle and mitosis

• What is the alternative to mitosis mentioned?

  Meiosis
• How do prokaryotic cells replicate?

  By binary fission
• How do viruses replicate?

  By injecting nucleic acid into host cells
• What are the stages of the cell cycle?

  Interphase, nuclear division, cytokinesis
• What phases make up interphase?

  G1, S, and G2 phases
• What is the purpose of G1 phase?

  Cell growth and organelle doubling
• What occurs during S phase?

  DNA replication
• What happens in G2 phase?

  Further growth and DNA checking
• What is the purpose of mitosis?

  Growth and repair of tissues
• How many key stages are there in mitosis?

  Four key stages
• What are the four stages of mitosis?

  Prophase, metaphase, anaphase, telophase
• What happens to chromosomes during prophase?

  They condense and become visible
• What occurs to the nuclear envelope during prophase?

  It starts to disintegrate
• What is the metaphase plate?

  The equator where chromosomes align
• What do spindle fibers attach to during metaphase?

  Chromatids and centromeres
• What happens during anaphase?

  Chromatids are pulled to opposite poles
• What energy molecule is required during anaphase?

  ATP
• What occurs during telophase?

  Chromosomes become longer and thinner
• What is cytokinesis?

  Splitting of the cytoplasm
• What is the mitotic index?

  Ratio of cells in mitosis to total cells
• How do you calculate the mitotic index?

  Divide cells in mitosis by total cells
• What might an exam question specify regarding cells?

  Look at only complete cells
• What are the stages of mitosis and their key events?

  • Prophase: Chromosomes condense, nuclear envelope disintegrates
  • Metaphase: Chromosomes align at the metaphase plate
  • Anaphase: Chromatids are pulled to opposite poles
  • Telophase: Chromosomes elongate, nuclear envelope reforms
• What are the roles of spindle fibers during mitosis?

  • Attach to chromatids at centromeres
  • Pull chromatids to opposite poles during anaphase
  • Help align chromosomes during metaphase
• What is the significance of the mitotic index in cell biology?

  • Indicates the proportion of cells undergoing mitosis
  • Helps assess cell proliferation in tissues
  • Useful in cancer research and diagnosis