Stages of Mitosis topic 1.6

Question 1

Interphase (2n)

Answer 1

• DNA is uncondensed (chromatin)
• DNA is replicated (S phase) to form
  genetically identical sister chromatids
• Cell grows in size and organelles are
  duplicated (G1 and G2)

Question 2

Prophase (2n)

Answer 2

• DNA supercoils and condenses
  (forms visible chromosomes)
• Nuclear membrane dissolves
• Centrosomes move to poles and
  begin to produce spindle fibres

Question 3

Metaphase (2n)

Answer 3

• Centrosome spindle fibres attach to
  the centromere of each chromosome
• Spindle fibres contract and move the
  chromosomes towards the cell centre
• Chromosomes form a line along the
  equator (middle) of the cell

Question 4

Anaphase
(2n → 4n)

Answer 4

• Spindle fibres continue to contract
• Sister chromatids separate and move
  to opposite sides of the cell
• Sister chromatids are now regarded as
  two separate chromosomes

Question 5

Telophase
(4n)

Answer 5

• Chromosomes decondense
  (DNA forms chromatin)
• Nuclear membranes form around the
  two identical chromosome sets
• Cytokinesis occurs concurrently

Question 6

Cytokinesis
(2n × 2)

Answer 6

• Cytoplasmic division occurs to divide
  the cell into two daughter cells
• Each daughter cell contains one copy
  of each identical sister chromatid
• Daughter cells are genetically identical