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Stages of Mitosis

Biology: AQA A Level, topic 2.2.2

Stages of Mitosis

In mitosis, chromosomes go through prophase, metaphase, anaphase and telophase. Interphase happens just before mitosis.

Interphase

Interphase

  • The cell prepares to divide.
  • DNA is replicated by semi-conservative replication. There are now two copies of every chromosome.
  • The organelles are also replicated.
  • More ATP is produced to be used in cell division.
Prophase

Prophase

  • The nuclear envelope breaks down and the nucleolus disappears. Chromosomes are left floating in the cytoplasm.
  • The chromosomes coil more tightly and become shorter and fatter. They can be seen under a light microscope.
  • Small protein bundles called centrioles move to opposite poles of the cell.
  • Microtubules form the mitotic spindle between the centrioles.
Metaphase

Metaphase

  • The chromosomes line up along the mid-line of the cell.
  • In metaphase, the chromosomes are maximally condensed.
  • They are attached to the spindle by the centromere.
Anaphase

Anaphase

  • The chromosomes break into two chromatids. The sister chromatids separate at the centromere.
  • The spindles contract and pull the chromatids to each pole of the cell.
Telophase

Telophase

  • The chromatids reach the opposite poles and begin to decondense (unravel), becoming chromosomes again.
  • Nuclear envelopes form around the chromosomes so there are now two nuclei.
  • The cytoplasm splits and two daughter cells are formed. The daughter cells are identical to the original cell and to each other.
  • The cell cycle starts again.
Way to remember the stages:

Way to remember the stages:

  • I (interphase).
  • Picked (prophase).
  • My (metaphase).
  • Apples (anaphase).
  • Today (telophase).

Test yourself on Stages of Mitosis

  • Stages of Mitosis

  • Which of these does NOT take place during interphase?

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