Transcript The Processes of Mitosis and Meiosis

The Processes of Mitosis and
Meiosis
Note: Quiz over this material
tomorrow (Thursday)
Mitosis
• Mitosis- is the process in which a cell
divides to form TWO IDENTICAL
CELLS.
• Follows specific order of events during the
process of mitosis:
– Interphase, Prophase, Metaphase, Anaphase,
Telophase.
Step 1: Interphase
• Interphase is how the
cell spends a majority
of it’s life cycle (up to
90%).
• Normal functions.
• When getting ready to
divide, the DNA winds
up into chromosomes
and duplicates but are
NOT in X form yet.
Step 2: Prophase
• The newly
created pairs
are now visible
as the X.
• Start moving to
line up in the
middle of the
cell.
Step 3: Metaphase
• Chromosomes, paired up, line up in the
middle of the cell “on top” of each other.
Step 4: Anaphase
• The paired
chromosomes
divide and pull
to each side of
the cell, which
is beginning to
elongate.
Step 5: Telophase
• Cell membrane starts pinching off.
• Chromosomes start unraveling.
Meiosis
• Process in which sex organs (ovaries and
testes) produce FOUR genetically
DIFFERENT daughter cells.
• Contains TWO cell divisions.
• Each daughter cell gets HALF the
chromosomes as the parent cell.
Prophase I
• DNA winds up,
forms into
chromosome
shapes.
• Each finds it’s
“homologous
pair”- it’s partner.
Metaphase I
• Line up “on top”
of each other, but
with it’s
homologous
partner next to it.
Anaphase I
• Sister chromatids
(the X shape)
move as a whole
to one side or the
other.
Telophase I
• Cell membrane begins
to pinch off into 2
cells, each with the
same number of
chromosomes as
parent cell.
Prophase II
• Start moving
towards middle of
cell (again).
Metaphase II
• Chromosomes
aligned in middle
“on top” of each
other. Again.
Anaphase II
• Chromosomes
pulled apart, move
to opposite sides,
again.
Telophase II
• Cell membrane
closes off,
chromosomes
unravel back to
DNA strands.
Again.
Assignment
• With a partner, create a ‘mnemonic device’
to help you remember
– The names of the phases and what occurs in
each.
– The differences between Mitosis and Meiosis.
• “Device” can be an acronym, lyrics, rap,
poem, or similar thing which can be shared
with others in the class.