Cell Cycle
Interphase, Mitosis, Cytokinesis, and
Cancer
Cell Division
• One cell divides
into 2 new identical
daughter cells.
• Chromosomes
carry the genetic
information (traits)
of the cell
How many Chromosomes are in
each of your cells?
Single
Chromosome
Diploid Cells
Having two of each
chromosome
Haploid Cells
Having only one
chromosome of each
“pair”
Normal Karyotype
Abnormal Karyotype
Gene Expression
• Cell differentiation occurs because
cells have the ability to turn off most
genes and only work with the genes
necessary for the cell to do its
specific job.
Cell Cycle
• Made of
three parts
– Interphase
– Mitosis
– Cytokinesis
Interphase
• The time in
between cell
divisions
when cells
grow;
longest part
of the cell
cycle.
Interphase -broken into 3 different parts:
1. G1 - First Growth
The cell grows in size
and increases # of
organelles
2. S - Synthesis
DNA replicates during
this time
Happens rapidly
3. G2 - Second Growth
Increase the size of
the cell again and
increase the # of
organelles again
Spindle
forming
Centrioles
Chromatin
Nuclear
envelope
Interphase
Centromere
Chromosomes (paired
chromatids)
Prophase
Cytokinesis
Spindle
Centriole
Telophase
Nuclear envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Mitosis
• Prophase
– Longest phase of mitosis
– Early prophase:
• Chromatin coils up into visible
chromosomes
• Sister chromatids are exact copies of each
other
Mitosis
• Prophase
– Late Prophase:
• The nucleus begins to disappear
• Centrioles move to opposite ends of the
cell
• Spindle fibers form between the
centrioles
Spindle
forming
Centrioles
Chromatin
Nuclear
envelope
Interphase
Centromere
Chromosomes (paired
chromatids)
Prophase
Cytokinesis
Spindle
Centriole
Telophase
Nuclear envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Prophase
(centrioles)
Spindle
Mitosis
• Metaphase
– Chromosomes
attach to the
spindle fibers by
their centromeres.
– Chromosomes line
up in the middle of
the cell.
Spindle
forming
Centrioles
Chromatin
Nuclear
envelope
Interphase
Centromere
Chromosomes (paired
chromatids)
Prophase
Cytokinesis
Spindle
Centriole
Telophase
Nuclear envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Mitosis
• Anaphase
– Centromeres split
– Chromatid pairs
separate and pull
apart to opposite
sides of the cell
Spindle
forming
Centrioles
Chromatin
Nuclear
envelope
Interphase
Centromere
Chromosomes (paired
chromatids)
Prophase
Cytokinesis
Spindle
Centriole
Telophase
Nuclear envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Mitosis
• Telophase
– Chromosomes
uncoil
– Nuclear
membrane
reappears
– A new
membrane
starts to form
between the
two new nuclei
Spindle
forming
Centrioles
Chromatin
Nuclear
envelope
Interphase
Centromere
Chromosomes (paired
chromatids)
Prophase
Cytokinesis
Spindle
Centriole
Telophase
Nuclear envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Cytokinesis
• Cytoplasm divides
• In Animals: cell membrane pinches in
to form a furrow
• In Plants: a cell plate is created to
form a new cell wall
Spindle
forming
Centrioles
Chromatin
Nuclear
envelope
Interphase
Centromere
Chromosomes (paired
chromatids)
Prophase
Cytokinesis
Spindle
Centriole
Telophase
Nuclear envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Cytokinesis
Control of the Cell Cycle
• If uncontrolled cell division occurs,
serious health issues are possible for
the surrounding tissue and the entire
organism; this malfunction causes
cancer.
– Interfer with normal processes
– Spread to other tissue (metastasize)
– Crowd out healthy tissue
Control of the Cell Cycle
– This can be cause by many factors:
• Environmental
• Smoking
• Pollution
• Radiation
• Viral Infections