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Cell Reproduction
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Prokaryotes
Bacteria
Eukaryotes
Plants & animals
Warm Up Mitosis Day #1
1. What process do prokaryotes use for cell
division?
2. What are the two cells produced called?
3. Cells spend the most time in which stage of
the cell cycle?
4. What happens during the S phase of the cell
cycle?
5. What is another name for mitosis?
Prokaryotes
 Lack
a nucleus
 Have a single chromosome
 Reproduce by binary fission
 Include bacteria
Steps in Binary Fission
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Used by bacteria
Cells increase their
cell mass slightly
DNA & cell
components are
replicated
Each cell divides into
2 daughter cells
Binary Fission of Bacterial Cell
E. Coli Dividing by Binary
Fission
Eukaryotes
 Contain
a nucleus &
membrane bound organelles
 Asexually reproduce cells by
mitosis
Cell Cycle
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Stages in growth &
division
G1 Phase
S Phase
G2 Phase
M Phase
Cytokinesis
G1 Phase
 First
growth stage
 Cell increases in size
 Cell prepares to copy its
DNA and organelles increase
in number
 Cells spend most of their
time in this phase.
Synthesis Phase (S)
 Copying
of all of DNA’s
instructions
 Chromosomes duplicated
 By the end of S stage the cell
nucleus contains two
complete sets of DNA
G2 Phase
 Time
between DNA synthesis
& mitosis
 Cell continues growing
 Needed proteins produced
M Phase ( Mitosis)
 Cell
growth & protein
production stop
 Cell’s energy used to make 2
daughter cells
 Called mitosis or
karyokinesis (nuclear
division)
Life Cycle of a Cell
Mitosis is a cycle with no beginning or end.
Interphase – Resting Stage
 Cells
carrying on normal activities
while preparing for division
 By end of interphase cell has two full
sets of DNA or chromosomes
 Cell is large enough to divide
 Occurs before mitosis
Interphase
Stages of Mitosis
 Prophase
 Metaphase
 Anaphase
 Telophase
Cells Undergoing Mitosis
Steps in Prophase
 DNA coils
tightly & becomes visible
as chromosomes
 Nuclear membrane disappears
 Nucleolus disappears
 Centrioles migrate to opposite poles
 Spindle fibers (microtubules) begins
to form from centrioles and move
toward center of cell
Eukaryotic Chromosome
Chromosome structure
DNA wraps around proteins called
histones forming chromatin. As
cell progresses into mitosis,
chromatin further condenses to
form small thick rods. One half of
a duplicated chromosome is called
a chromatid. Together they are
called a sister chromatid. Sister
chromatids are held together by a
centromere.
Human Chromosomes
Steps in Metaphase
 Spindle
fibers from centrioles
attach to each chromosome at
the centromere.
 Cell preparing to separate its
chromosomes
 Cell aligns its chromosomes in
the middle of the cell
Metaphase
Steps in Anaphase
 Cell
chromosomes (sister
chromatids) are separated
 Spindle fibers shorten so
chromosomes pulled to ends of
cell
Anaphase
Steps in Telophase
 Separation
of chromosomes
completed
 Cell Plate forms (plants)
 Cleavage furrow forms(animals)
 Nucleus & nucleolus reform
 Chromosomes uncoil and
spindle fibers fall apart
Telophase
Plant
Animal
Cytokinesis
 Occurs
after chromosomes
separate
 Forms two, identical
daughter cells
 Cells will enter interphase
and begin the cycle again.
Cytokinesis
Cell Plate formed by the golgi
apparatus can’t pinch like animal
cells because of cell wall.