CELL CYCLE
The cell life cycle involves series of changes a cell well undergo during its life the whole cycle can be divided into two major periods 1. cell growth (INTERPHASE) 2. DIVISION
Interphase:: it includes the total period starting from the birth of the cell to the times when it undergoes division in this phase the cell undergoes the routine activities and is metabolically active in addition during this phase the cell prepares for next cell division interphase can be subdivided into G1 S and G2 subphases in the G1 phase cells are metabolically active and synthesize the necessary proteins the length of G1 phase is variable and depends on the type of cell at the end of G1 phase centrioles start to replicate (formation of two identical copies ) in the S phase DNA start replicating and chromatin formation occurs in the G2 PHASE enzymes and other proteins needed for division are synthesized and moved to their proper sites in addition in this phase centriole replication is complete
every life including human being began as a single cell it is the process of cell division which result in trillions of cells that form a recognizable human being the cell division takes place by any of the two methods 1. mitosis a type of cell division in which the original parent cell splits into two daughter cells keeping the chromosome number constant
2.meiosis a type of cell division in which the chromosome number is reduced to one half this occurs only in gonads during the formation of gamets the resultant gamets are potentially capable of combining with gamets of opposite sex to form a zygote
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