What is the difference
between the hydra’s
offspring growing off of the
parent hydra and the two
beetles mating to create their
offspring?
How could a cell make
an exact copy of itself?
Engage/pH 0708
Remember chromosomes?
Explain/pH 0708
Mitosis
• Mitosis-division of the cell nucleus.
• Cytokinesis-division of the cytoplasm.
Cell Cycle
• During the cell cycle,
a cell grows,
prepares for
division, and divides
to form two daughter
cells, each of which
then begins the
cycle again.
Exploring Mitosis
Mitosis
• Cell Division – Cell copying
– Creates new cells with identical DNA
– If a human cell goes through mitosis, it starts
with 46 chromosomes and ends up with 46
chromosomes in the new cell.
– These cells are called 2n – they have two
copies of each chromosome
• Diploid
Interphase
• The cell grows
and replicates its
DNA and
centrioles.
Stages of Mitosis-Prophase
• First and Longest
Stage of Mitosis
• Chromosomes
appear
• Nuclear envelope
breaks down
Metaphase
• The chromosomes
line up across the
center of the cell.
Anaphase
• The chromosomes
are separating and
moving to opposite
sides of the cell.
Telophase
• The chromosomes
gather at opposite
ends of the cell and
lose their distinct
shapes.
• Two new nuclear
envelopes will form.
• Last phase of Mitosis.
Cytokinesis
• The cytoplasm
divides in half.
• Each daughter cell
has an identical set of
duplicate
chromosomes.
Video of Mitosis
• Mitosis Video
The Cell Cycle
If a cell “gets stuck”
in the cell cycle and
divides
uncontrollably, a
tumor (mass of
cells) will form.
The cell is a
cancer cell.
Cancer cells lose
the ability to
regulate mitosis
and do not
recognize the signs
to stop dividing
(Contact Inhibition).
SOME TUMORS
MRI of Brain Tumor
Asexual Reproduction
• One individual organism creates offspring
that are genetically identical to itself.
• This occurs through MITOSIS.
– Sea stars, Sea anemones, hydra, some
plants
Hydra Budding