Download The Cell Cycle

THE CELL CYCLE
THE BEGINNING
INTERPHASE
The 1st step of the cell cycle
 The longest step of the cell cycle
 Is made up of 3 parts (G1, S, and G2) allow the
cell to grow and DNA to be copied (replication or
duplication)
**Replication = writing a signature (it isn’t exact
but it looks the same each time)
** Duplication= Xerox copy (the copy is exact)

THE MIDDLE
ANIMAL CELL MITOSIS
Is an asexual process (without intercourse  single
parent)
 Is a multistep process that allows the nucleus to divide
creating two daughter cells
 Has the greatest amount of steps (four) of all the parts of
the cell cycle
 Is a relatively short cycle
 Is carried out by all human cells (somatic cells) but sex
cells

STEPS OF MITOSIS
PROPHASE
Is the 1st of mitosis
 The replicated DNA is seen as a dense mass called
chromatin in the early stages
 As prophase continues the chromatin condenses
forming chromosomes
 The centrioles (a bundle of microtubules) express
asters (that will help form spindle fibers)
 The nuclear membrane begins to break down

METAPHASE
 The
chromosomes line up along the
equator of the cell
 The centrioles migrate to the poles of
the cells
 The spindle fibers attaches to the
central structure of the chromosome
(centromere)
 The nuclear membrane is totally
diminished
ANAPHASE
 The
cell begins to elongate (stretch out)
 The spindle fibers begin to retract (pull
back)
 The chromosome pair comes apart
staying attached to the spindle fiber
**Each chromosome has a centromere
**A chromosome without a centromere is
called a chromatid
TELOPHASE
 The
elongated cell begins to pinch
in
 The spindle fibers diminish
 Two new nuclear membranes form
around each group of separated
chromosomes
 The final step of nuclear division
giving rise to two new nuclei
THE END
CYTOKINESIS
The division of cytoplasm
 Last step of the cell cycle that form two daughter
cells
** The daughter cells that are produced are
genetically identical to the parent cell (clones)
** Since the chromosome number is preserved from
start to finish it is referred to diploid (2n)
