Download mitosis

Reproduction & Cell Cycle
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Homework
Objectives
• Be able to explain how/why mitosis produces
identical cells
• Know the four stages of mitosis, plus
cytokinesis
• Be able to draw and recognize a picture of each
stage
• Be able to explain the major event that happens in
each stage
• Be able to say what order they happen in
Mitosis Movies
• http://www.cellsalive.com/mitosis.htm
http://www.johnkyrk.com/mitosis.html
http://youtube.com/watch?v=0oJZDKdperU&feature=
related
http://youtube.com/watch?v=rgLJrvoX_qo&feature=re
lated
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/a
nimation__mitosis_and_cytokinesis.html
Cell Cycle Model
• To help you learn, you will:
• Make a moving model of the cell
• Draw a picture of what it looks like in each stage
• Write the important thing that happens in each
stage
• Remember: your real goal is to be able to
say why mitosis produces identical cells…
Cell Cycle Model
• Each group gets one baggie. Do not eat
your candy, it’s gross and you need it to
make your cell.
• (I’ll give you uncontaminated candy at the end, if
you earn it!)
• Clear off your table. Keep out the two
handouts and something to write with.
• Do not open the baggie, follow my
instructions!
Cell Cycle Model
• Long piece of string = cell membrane.
• Small piece of string = nuclear
membrane or nuclear envelope.
Cell Cycle Model
• Gum Drops = centrioles. Put THREE of
them in the cell cytoplasm.
Cell Cycle Model
• Worms/Good n Plenties =
chromosomes.
• Each kind of candy (gummi worm, sour
worm, good n’ plenty) is one chromosome
number.
• Two candies of the same color =
homologous chromosomes.
• Put ONE of each homologous
chromosome in the nucleus.
Cell Cycle Model: Interphase
• We begin in interphase. Interphase in a cell is
different than this model; the chromosomes are
unwound enough that you can’t see each one.
• When the cell needs to divide, it starts by
replicating its DNA in S phase.
• Replicate your chromosomes. Each homologous
chromosome is now made of two sister chromatids.
Cross them over at the middle. This point, where the
sister chromatids connect, is called the centromere.
• It also replicates its centrioles.
Cell Cycle Model: Interphase
• Human chromosomes ready
for mitosis.
• Same as the image before,
but now each homologous
chromosome is made of two
identical sister chromatids
joined at the centromere.
Cell Cycle: Interphase
• So, interphase: Normal metabolism.
Replicates DNA in S phase, turning
each chromosome into two sister
chromatids.
Cell Cycle Model: Mitosis
• Prophase
• Chromosomes condense and
are visible.
• (Our model is weird like this.)
• Centrioles separate.
• Spindes begin to form
between the centrioles.
• Nuclear envelope begins to
break down.
Cell Cycle Model: Mitosis
• Metaphase:
• Chromosomes line up
across the center of the
cell.
• Each centromere is
connected to a spindle.
Cell Cycle Model: Mitosis
• Anaphase:
• Sister chromatids separate.
• Spindles pull each chromatid
towards one side of the cell.
• For each chromosome, one
chromatid is pulled to one
side, and the other chromatid
is pulled to the other side.
Cell Cycle Model: Mitosis
• Telophase:
• The chromosomes are pulled
to opposite ends of the cell.
• Spindles let go of their
centromeres.
• Two new nuclear envelopes
form.
Cell Cycle Model: Cytokinesis
• Cytokinesis:
• The cytoplasm and organelles
copy and move away from the
middle of the cell. (not modeled)
• The cell membrane moves in
towards the center and the cell
pinches in half.
• The end result is two smaller but
identical cells, called daughter cells.
Cell Cycle
• If a cell with 32 chromosomes (16
different kinds of chromosome) goes
through mitosis, how many
chromosomes will each of its daughter
cells have?
• If a diploid cell goes through mitosis, will
its daughter cells be diploid or haploid?
IPMATC
• Interphase
• G1, S, G2
• Mitosis
•
•
•
•
Prophase
Metaphase
Anaphase
Telophase
• Cytokinesis
• It can take as little
as ten minutes or
as long as 2
hours for a cell to
divide.
• Some cells divide
almost daily,
others never do.
Cell Cycle Model
• Reset your candy cell to how it was at the
beginning.
• Repeat what we just did. As you go through,
say out loud what stage you’re modeling. As
you manipulate some part or another, say its
name.
• Work as a team, I’m trusting you with the task
of making sure that both you AND everybody
at your table gets this.
Latin/Greek Word Parts
• (Homo
• “Same”)
• Inter
• “Between”
• Centr
• “Middle, central”
• (Pro
• “Forward”)
• Meta
• “After”
• Ana
• “Upward, across, away, apart”
• Tel
• “End, far”
For the rest of the block:
• Go through the candy cell cycle some more
times if you aren’t confident that you know the
steps.
• Complete your vocabulary sheet, working with
others is encouraged. Use a textbook if you’d
like.
• Before your leave, put everything back in your
bag, and get a fresh candy!