Mitosis

• What is mitosis?

  Nuclear division producing two identical daughter nuclei
• How many main stages can mitosis be divided into?

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

  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• How many chromosomes do humans have?

  46 chromosomes
• Why are different colors used for chromosomes in diagrams?

  To show parental contribution of chromosomes
• What happens during prophase?

  Chromosomes condense

  The two centrioles start to migrate to opposite poles

  Spindle fibres start to emerge from the centrioles

  The nuclear envelope breaks down into vesicles

  The nucleolus disappears
• What are sister chromatids?

  Identical chromatids joined at the centromere
• What do centrosomes do during prophase?

  Move towards opposite poles
• What begins to emerge from the centrosomes during prophase?

  Spindle fibres
• What happens to the nuclear envelope during prophase?

  It breaks down into small vesicles
• What happens to the nucleolus during prophase?

  It disappears
• What occurs during metaphase?

  Centrioles reach opposite poles and have spindle fibres extending from them

  Chromosomes line up at the equator of the cell

  Spindle fibres attach to chromosomes by their centromere

  Each sister chromatid is attached to a spindle fibre from the opposite centrosome
• What are kinetochores?

  Specific proteins that attach to centromeres
• What happens during anaphase?

  Sister chromatids divide at the centromere

  Spindle fibres begin to contract and pull chromatids to opposite poles
• What do spindle fibres do during anaphase?

  They shorten and pull chromatids to opposite poles
• What happens to the nuclear envelopes during telophase?

  They begin to reform around chromosomes
• What is the significance of mitosis?

  It enables growth, repair, and asexual reproduction
• What are the biological processes that mitosis is fundamental to?

  • Growth of multicellular organisms
  • Replacement of cells and repair of tissues
  • Asexual reproduction
• How do unicellular zygotes grow into multicellular organisms?

  By dividing through mitosis
• Where does growth occur in plants?

  In meristems or growing points
• How does mitosis help in tissue repair?

  By replacing damaged cells with identical cells
• Which tissues in humans are replaced rapidly by mitosis?

  Skin and gut lining tissues
• What is asexual reproduction?

  Production of offspring by a single parent
• How do unicellular organisms reproduce asexually?

  By cell division resulting in identical offspring
• What is budding in asexual reproduction?

  New individuals grow from the parent organism
• Which organisms exhibit budding?

  Hydra and yeast
• What are runners in asexual reproduction?

  Structures that grow from the parent organism
• Which plants produce runners?

  Strawberries
• What does PMAT stand for?

  Prophase, Metaphase, Anaphase & Telophase
• What occurs during telophase?

  Chromosomes arrive at opposite poles & start to decondense

  Nuclear envelopes start to reform around each group of chromosomes

  Spindle fibres break down

  New nucleoli form in each nucleus
• What stage of mitosis is this?

  A) Interphase

  
• What stage of mitosis is this?

  A) Prophase

  
• What stage of mitosis is this?

  A) Metaphase

  
• What stage of mitosis is this?

  A) Anaphase

  
• What stage of mitosis is this?

  A) Telophase