152 ^|

A Handbook of Biology

05

In human cell cycle, with an average of 24 hours

duration the mitosis lasts for only about an hour.

M Phase includes karyokinesis (nuclear division)

and cytokinesis (division of cytoplasm).

06

Some cells do not show division. E.g. heart cells

07

Many other cells divide only occasionally to replace

damaged or dead cells.

08

These cells that do not divide further exit G1 phase and

enter an inactive stage called quiescent stage (G0).

Such cells remain metabolically active but do not

proliferate unless called on to do so depending on the

requirement of the organism

09

Mitosis has 4 stages: Prophase, Metaphase, Anaphase

& Telophase.

10