Today’s Plan: 8/26/10
• Bellwork: Review K/NTK list and rubric
(20 mins)
• Cell Cycle Lab (30 mins)
• Cell Size Limits Workshop (the rest of
class)
• Pack/Wrap-up (last few mins)
Today’s Plan: 8/27/10
• Bellwork: Nanomedicine Demo (20 mins)
• Limits to Cell Size Workshop (20 mins)
• Cell Size Limits and Foldable Notes (40
mins)
• Pack/Wrap-up (last few mins of class)
Today’s Plan: 8/30/10
• Bellwork: Finish Foldable (30 mins)
• Cell Specialization Activity (30 mins)
• Project Work time (the rest of the period)
Today’s Plan: 8/24/09
• Bellwork: Finish Mitosis side of foldable,
set up Meiosis (15 mins)
• Finish Cell cycle activity/Cancer Activity
(30 mins)
• Finish foldable (the rest of class)
Today’s Plan: 8/25/09
• Bellwork: Blue Diamond #3 and Q&A (20
mins)
• Mitosis and Meiosis Quiz (as needed)
• Probability Lab (the rest of the period)
• Pack/Wrap-up (last few mins of class)
Sexual vs. Asexual Reproduction
• Sexual=an exchange or new combination of
DNA from 2 organisms (recombination)
– In the cells of each organism, ½ of the DNA
came from the mother and ½ came from the
father @ the original fertilization that occurred
to make the organism
• Asexual=No exchange or recombination of
DNA (only 1 organism is involved,
cloning.)
Cellular Reproduction
• 2 Types:
– Cell cycle and Mitosis=body cells are copied
(cloned) to be identical to the original
– Meiosis=makes gametes which contain ½ of the
DNA of the original cell
• Recombination occurs via Crossing Over
• Once meiosis occurs, fertilization can
happen. Is this sexual?
Notes, Cell Growth and Division
• Cell Size
– Determined by the SA:V ratio
– Also regulated by enzymes (you can have too
many, not enough, or the wrong ones)
– Determined by contact inhibition (cells
touching other cells rarely divide)
– Cancers happen because the cell cycle is not
properly regulated.
• Oncologists believe that this is due to genes which
control enzyme production.
• Cancer spreads via metastasis (metastatizing), when
they enter the circulatory system
The Cell Cycle
• Includes 3 steps
– Interphase, which has a growth, synthesis, and
pre-division phase
– Mitosis, which includes the NUCLEAR
division along with its genetic material
(Prophase, Metaphase, Anaphase, Telophase)
– Cytokinesis, which involves the plasma
membrane pinching off, dividing the cytoplasm
equally between the 2 cells.
• Can there be mitosis without cytokinesis?
• Can there be mitosis without interphase?
Cellular DNA
• DNA during interphase exists as chromatina long, unraveled string.
• During Prophase, the DNA coils up and
condenses to make chromosomes
– chromosomes consist of sister chromatids held
together by a centromere (see overhead for
demo and draw on your own)
– Chromosomes are split apart during mitosis at
the centromere.
– Full set of chromosomes=diploid
– half set of chromosomes=haploid
Mitosis
• After the cell has grown, duplicated its
DNA and Centrioles (animals), it has
completed interphase and is ready for
Mitosis.
• Mitosis begins with Prophase, where the
chromatin becomes chromosomes, and the
nuclear envelope disappears. The centrioles
migrate to opposite poles of the cell, and the
spindle fibers begin to form. Draw this
phase.
Mitosis cont.
• Following prophase is Metaphase-which
means “middle-phase.” The chromosomes
migrate to the middle of the cell and are
attached to spindle fibers at their
centromeres. Draw this phase
• Once the cells have lined up, they are pulled
apart at their centromeres and moved
toward the poles. This is anaphase. Draw
this phase.
Mitosis cont.
• Finally, Telophase happens when the nuclei
of the daughter cells re-forms and the DNA
unravels into chromatin. Spindle fibers and
centromeres disappear. Draw this phase.
• After Mitosis, cytokinesis happens.
Meiosis
• Steps include Interphase, Prophase I, Metaphase I,
Anaphase I, Telophase I, Prophase II, Metaphase
II, Anaphase II, and Telophase II
• Both Telophases are accompanied by cytokinesis.
• Compare and contrast the two (see overhead and
video clip)
• Meiosis Makes Gametes (sperm and egg)
Gametogenesis
• Means making gametes
• In men, results in 4 sperm cells, all identical
in size.
• In women, results in 4 primary oocytes, 3 of
which surrender their cytoplasm to the 4th.
The 3 small become polar bodies. The 4th
becomes the mature egg (secondary
oocyte).
Chromosome number
• Chromosome Number is determined by how many
chromosomes are visible at Metaphase. Why?
• Diploid-2 of each kind of chromosome, otherwise
expressed as 2n. Means that a person has a
complete set of chromosomes at Metaphase
• Haploid-1 of each kind of chromosome, otherwise
expressed as n.
Counting Chromosomes
• We take cells and treat them with a chemical that
stops spindle fiber formation. What effect would
this have?
• We then submerge cells in pure H2O. What effect
would this have?
• When the Chromosomes settle out on a slide, we
then take a picture of them and cut them out to be
arranged in an organized way, called a
Karyotype.
• Homologous Chromosomes are lined up together.
Karyotyping and errors
• The splitting of chromosomes is called
Disjunction.
• Errors in this process are called Nondisjunction.
• What effects could this have on a
karyotype? Trisomy, monosomy
• See overhead.