sábado, 2 de febrero de 2013

Mitosis Phases


                   Growth stage
                    Cell division 
                              Mitosis
                              Cytokinesis
 

1.- Prophase

-         Strands of DNA condense and thicken to become visible duplicated chromosomes.
-         Each chromosome consists of two identical chromatids held together by a centromere.

-         Nuclear membrane disappears.
-         Spindle fibres start to form between two centrioles at each pole.

2.- Metaphase

-         A spindle fibre from each pole attaches  to each sister chromatid at the centromere.
-         Spindle fibres align the chromosomes along the cell’s equator (middle of the cell).

3.- Anaphase

-         The centromere splits apart.
-         Each daughter chromosome is pulled to opposite poles by the spindle fibres.

4.- Telophase

-         Telophase begins when the chromatids reach the opposite poles.
-         The chromosomes become less visible.
-         A new nuclear membrane forms around each groups of daughter chromosomes.