CELL CYCLE
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GROW
DEVELOP
REPLACE OR REPAIR
PRODUCE NEW CELLS
CELL CYCLE PHASES
TWO MAIN PHASES:
INTERPHASE
MITOTIC PHASE
Why divide instead of growing
larger?
Moving enough
nutrients in or
moving all the
waste materials
out
Nucleus
Capacity- like
you and me,
the nucleus
can only
handle or do
so much
Contains 3
stages:
 G1
 S
 G2
Contains 2
stages:
 Mitosis
 Cytokinesis
Phases of the cell cycle
INTERPHASE
 Period of growth and
development
 Most of the cell cycle
 DNA copied (chromatin)
 Cell prepares for division
INTERPHASE-S STAGE
 Cell continues to grow
 Copies DNA
 DNA coils & forms a
chromosome
 Identical
join and DNA
arranged in pairs called
duplicated chromosomes
INTERPHASE-G1 STAGE
 Rapid growth
 Normal cell functions occurs
S STAGE CONTINUED
 Two identical chromosomes,
called sister chromatids, make up
a duplicated chromosome
 Sister chromatids held together
by centromere
If a cell has 11 duplicated chromosomes, how many
chromatids does it have?
INTERPHASE G2 STAGE
ORGANELLE REPLICATION
 Period of growth and final
prep for Mitosis
 Cell stores energy needed
for Mitotic Phase
 Before division organelles are
copied so new cells can function
 This copying occurs during all
stages of interphase
MITOTIC PHASE
PHASES OF MITOSIS
 Mitosis: nucleus and
contents divide
 Cytokinesis: cytoplasm and
its contents divide
 Two daughter cells result
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Prophase
Metaphase
Anaphase
Telophase
PROPHASE
 Coiled chromatin form visible
duplicated chromosomes
 Nucleolus disappears
 Nuclear membrane bye!
 Spindle fibers form in
cytoplasm
METAPHASE
 Shortest phase
 Duplicated chromosomes
line up in middle (equator)
of cell (split occurs there)
 Incorrect genetic
information can=cancer
ANAPHASE
 Sister chromatids separate as
spindle fibers pull apart into two
identical single stranded
chromosomes
 Cell gets longer during process
 Phase ends opposite end of cell
TELOPHASE
 Spindle fibers disappear
 Chromosomes uncoil & nuclear
membrane forms @ both ends
(two new nuclei are formed)
 Described as reverse of
Prophase
CYTOKINESIS
 Cytoplasm divides forming two
new daughter cells
 Division is different for plant and
animal cells
PLANT CELLS
 A new cell wall forms in the
middle of the plant cell.
 Vesicles join form a cell plate
 Cell plate grows outward
toward cell wall until two new
cells form
ANIMAL CELLS
 Membrane contract/squeezes
causing furrow in middle of cell
 Furrow deepens until cell
membrane comes together and
divides the cell
 See page 102
RESULTS-CELL DIVISION
 Form of asexual reproduction for
some unicellular organisms
 Allows multicellular organisms to
grow & develop from one cell
 Worn out cells replaced (skin)
 Repair damage (broken bones)