Cell cycle

The Eukaryotic Cell Cycle

This can be described as a distinct and ordered series of events that lead to the replication of a cell, these highly specific events must be highly regulated.  There are two main factors associated with efficient replication of the cell and these must be correct before the cell cycle can commence. 

Firstly the cell must be the correct size if it were to small then after subsequent cell divisions the cell would become too small and become disfunctional. 

Secondly the genetic material must be in the correct state and must only be replcated once per cell cycle. 

Also the cell cycle must only occur in tissues which require the process to take place, uncontrollable cell divsion can lead to the formation of tumours and ultimately formation of cancers. 

The cycle consists of four distinct stages:

M (Mitosis) Phase

G1 (Growth) Phase

S (Synthesis) Phase

G2 (Growth) Phase

Cdk and cyclin

Cyclin association with Cytokine dependant kinases (Cdk) activates protein kinase activity.

Cdk phosphorylation of intracellular proteins regulates major events in the cell cycle. (Alberts 2002)