DNA QUESTIONS

1. The table below diagrammatically shows the stages of mitosis in eukaryotic cells
a Complete the table by filling in the missing stage labels and descriptions

Interphase

  • chromatin not visible
  • DNA, histones and centrioles all replicated

Prophase

  • chromosomes condense / become visible
  • centrioles at opposite poles of cell
  • nucleolus disappears
  • phase ends with the breakdown of the nuclear membrane

Metaphase

  • chromosomes align along equator of cell

Anaphase

  • centromeres split / chromatids separate
  • chromatids move towards poles

Telophase

  • spindle fibres disperse
  • nuclear membraness from
  • nucleoli form

Cytokinesis

  • In animal cells a ring of actin filaments forms round the equator of the cell, and then tightens to form a cleavage furrow, which splits the cell in two.
(8)
b

Explain the importance of mitosis to living organisms.

  • produces genetically identical cells
  • therefore daughter cells are capable of producing same proteins as parent cell
  • for growth / for repair
  • for asexual reproduction
(any 3)