Mitosis

• Interphase stages

  • G1 phase
  • S phase
  • G2 phase
• What happens in G1?

  • cell is growing
  • making proteins for transcription/translation
  • organelles replicated
• what happens in S phase ?

  • DNA replication (semi-conservative)
  • Each chromosome replicates to form two identical copies called sister chromatids. 
  • Attached at the centromere
• what happens at G2 ?

  • cell is getting ready for mitosis
  • keeps growing
  • proteins needed for mitosis made
• what happens at G2 checkpoint?

  • DNA replicated without damage
• Mitosis - Division of the nucleus
• Cytokinesis - the division of the cytoplasm into two daughter cells
• what happens at G0?

  • not preparing for division
  • not in the cell cycle (neurons)
• Interphase

  DNA unravelled/replicated , organelles replicated and ATP content increased
• Prophase

  • Chromosomes condense (shorter and fatter)
  • Ting bundles of proteins ( centrioles ) start to move to opposite end to form a spindle
  • Nuclear envelope breaks down
  • chromosomes lie free in cytoplasm
• Metaphase

  • chromosomes attach to the spindle via the centromere
  • line up on metaphase plate/equator
  • M checkpoint - chromosomes attach to spindle
• Anaphase

  • centromere divide separating each pair of sister chromatids
  • spindle contract - pulling chromatids to opposite ends - centromere first
• Telophase

  • chromatids reach opposite poles of spindle
  • long and thin and called chromosomes
  • nuclear envelope forms to create two nuclei
• Cytokinesis

  • cytoplasm divides
  • animal cell -cleavage furrow forms to divide cell membrane