Mitosis: Skills (DP IB Biology)

Identifying Phases of Mitosis

• Cells undergoing different stages of the cell cycle can be identified using photomicrographs taken from microscope slides

• Cells undergoing certain stages of the cell cycle have distinctive appearances

Interphase

• As cells spend the majority of the cell cycle in this stage then most cells will be in this stage

• The chromatin is visible (however chromosomes are not) so the nuclei have a dark appearance

Prophase

• Chromosomes are visible

• The nuclear envelope is breaking down

Metaphase

• Chromosomes are lined up along the middle of the cell

Anaphase

• Chromosomes are moving away from the middle of the cell, towards opposite poles

• As they are pulled from the centromere through the cytoplasm, the chromosomes tend to have a characteristic 'V' shape

Telophase

• Chromosomes have arrived at opposite poles of the cell

• Chromosomes begin to uncoil (are no longer condensed)

• The nuclear envelope is reforming

Cytokinesis

• Animal cells: a cleavage furrow forms and separates the daughter cells

• Plant cells: a cell plate forms at the site of the metaphase plate and expands towards the cell wall of the parent cell, separating the daughter cells

Identification of phases

Micrograph showing a cell undergoing prophase (P)

Micrograph showing cells undergoing metaphase (M) and anaphase (A)

Micrograph showing cells undergoing metaphase (M) and anaphase (A)

Micrograph showing a cell undergoing anaphase (A)