Cell Life Cycle

G1

growth/replacing organelles

G1 Checkpoint

Checks external conditions, cell size, DNA damage

S

DNA Synthesis

G2

nuclear envelope exists, nucleus has one or more nuceloli, two centrosomes form through duplication from one, chromosomes still chromatin. Growth of structures needed for mitosis.

G2 Checkpoint

checks DNA damage after duplication

Prophase

Chromasomes now seen, nucleoli disappear, duplicated chromosome appears as two identical sister chromatids, mitotic spindle forms, centrosomes move apart

Prometaphase

nuclear envelope fragments, microtubules invide nuclear area, chromosmes condense more, kinetichore forms at centromere, microtubuyles connect at kinetochores, non attached microtubules lengthen cell

metaphase

centromeres now completely polarize, chromosomes arrive at metaphase plate, kinetichores attach from opposite poles

M Checkpoint

checks for proper orientation and attachment of chromosomes

Anaphase

cohesin proteins cleave, microtubules pull daughter chromosomes to opposite sides, cell elongates, two sides have equal chromosomes by end

Telophase

Nuclear envelope arise from fragments of parent cell nuclear envelope and other parts from endomembrane system, nucleoli reappear, chromosomes become chromatin, spindles go away (depolymerize), mitosis completes

cytokenesis

starts during late telophase, cleavage furrow pinches cell in two in animal cells.