Mitosis

• What is the purpose of cell division

  • Production of new orgniasms
  • Growth
  • Cell replacement
• How do bacteria divide

  binary fission
• Describe binary fission

  X

  A) Origin of replication

  B) 2 copies of the origin

  C) Cell elongates so the origin is at either end

  D) Membrane grows inwards

  E) 2 identical daughter cells

  
• What are two stages of the cell cycle

  Mitotic phase and interphase.
• What are the stages of interphase

  G1, S, G2.
• What are the stages of the mitotic phase

  Prophase, Prometaphase, Metaphase, Anaphase, Telophase, cytokinesis.
• What happens in G1.

  Organelles are replicated.
• What happens in S phase.

  Semi-conservative replication.
• What happens in G2.

  Centrosomes replicate. Microtubules form an aster.
• What is an aster.

  A centrosome with microtubules extending from it.
• Briefly describe mitosis

  2 sister chromatids are replicated and separated to produce identical daughter cells.
• Describe cytokenesis

  cytoplasmic division which results in 2 daughter cells.
• What is the mitotic spindle made of

  Chromatid pairs. Tubules. Centrosomes.
• What is the centrosome

  Pairs of centrioles.
• What are the 3 tubules in the mitotic spindle.

  Astral, Kinetochore, Non-kinetochore [Polar].
• What are the two types of dynein motors in mitosis


  Astral and kinetochore.
• What is the name for the kinesin motor in mitosis 


  Non-kinetochore [Polar]
• Which tubules push in mitosis


  kinetechore.
• Which tubules pull in mitotis


  Astral and kinetechore.
• What do astral move


  Centrosomes
• What do kinetochore move


  Chromosomes
• What does non-kinetochore move 


  polar microtubules
• What is a polar microtubule

  Where the microtubules overlap
• How do astral motors work

  Depolymerise and shorten astral microtubules to pull them towards the poles.
• When do astral microtubules work

  Prophase
• How do kinetochore microtubules work

  Depolymerise and shorten kinetochore tubules in order to move chromosomes towards centrosomes.
• When do kinetochore microtubules work

  Anaphase
• How do non-kinetochore microtubules work

  Polymerise and lengthen polar microtubules. Pushes polar microtubules resulting in elongation of the cell.
• When do non-kinetochore motors work

  Telophase and cytokinesis.
• Describe prophase

  • chromatin Condense
  • Nucleolus disappears
  • Centrosomes move away
  • Mitotic spindle forms
• Describe prometaphase

  • Nuclear envelope breaks down
  • Microtubules interact with their targes
• Describe metaphase

  • Centrosomes at opposite poles
  • Chromosomes line on the metaphase plate
  • Sister chromatids are on different spindle fibres
• Describe Anaphase

  • Dynein moves chromosomes to pole
• Describe Telophase

  • Kinesin elongates kintetochore
  • Cell elongates
  • Chromatin decondense
• Describe Cytokinesis for animals

  Microfilaments form a ring at the furrow. Ring contracts using myosin motors and actin filaments.
• Describe cytokinesis in plants

  Cell plates form at the equator. Cell wall forms.