Transcript Cell Cycle, Mitosis, and Meiosis

Mitosis/ Meiosis
http://www.youtube.com/watch?v=-bKyT5_s_dE
SC.912.L.16.14
• describe the specific events that occur in each of the stages of the cell cycle (which include the
phases of mitosis:)
– interphase (Gap 1, Synthesis, Gap 2)
– prophase
– metaphase
– anaphase
– telophase
– cytokinesis
• explain how new cells are created through mitosis
• explain why maintaining chromosome number during asexual reproduction is important
SC.912.L.16.8
• describe cancer as uncontrolled cell growth that may have resulted from mutations affecting cell
cycle-regulating proteins
SC.912.L.16.16
• describe the process of meiosis, including independent assortment and crossing over
• explain how reduction division results in the formation of haploid gametes or spores
SC.912.L16.17
• differentiate the processes of mitosis and meiosis
• model or diagram the process of mitosis and meiosis
• explain how sexual and asexual reproduction may contribute or limit genetic variation
Cell Cycle
• Gap 1 (G1)- cells perform normal
function, cells grow and replicate
organelle; checkpoint
• Synthesis (S)- cell synthesizes a
whole new copy of DNA (in nucleus
in eukaryotic cells), at end of stage
there are two copies of DNA
• Gap 2 (G2)- additional growth;
second checkpoint
• Mitosis (M)- two parts: mitosis and
cytokinesis
– Mitosis is division of cell nucleus
and DNA inside
– Cytokinesis is division of contents
(cytoplasm)
Interphase
What are the stages of mitosis and how
do they produce identical copies of cells?
Mitosis= cell division
Before Cell Division
▫ Interphase- Chromosomes duplicate,
cell prepares for mitosis
Mitosis Stages
PMAT
▫ Prophase- Chromosomes condense
▫ Metaphase- Chromosomes meet in
the middle
▫ Anaphase- Chromosome pull away
▫ Telophase- cell separating
▫ Cytokinesis- Separation of cells is
complete
How does mitosis maintain the
chromosome number in the parent cells?
• The chromosomes duplicate (make a copy of)
themselves before cell division or mitosis.
– Occurs in interphase, when the cell is preparing to
divide.
How does mitosis allow for asexual
reproduction?
• Mitosis is making an exact copy of the cell. In
my mitosis there no exchange or
recombination of DNA.
– Examples of Asexual Reproduction: Cutting off a
piece of plant and replanting it, budding, and
binary fission in bacteria.
What are the steps in meiosis that result
in the formation of haploid gametes?
• Haploid= half the
number of
chromosomes
▫ Ex: Human gametes
are haploid (23
chromosomes)
• The chromosomes in
the original cell
duplicate and the cell
then goes through
two cell divisions.
http://www.youtube.com/watch?v=Ba9LXKH2ztU&feature=related
Why is meiosis necessary for sexual
reproduction and how does it allow for
creating genetic diversity?
• Meiosis creates gametes.
• Each cell created as a result
of meiosis are different
because of independent
assortment and crossing
over
How are mitosis and meiosis similar but
different?
Mitosis
Meiosis
Starts with 1 diploid cell
Ends with 2 diploid cells
Starts with 1 diploid cell
Ends with 4 haploid cells
Occurs in somatic cells
Creates gametes (sex cells)
Creates cells that are
identical
Creates cells that are
genetically different
How can independent assortment and
crossing over occur during meiosis?
• Both crossing over and independent assortment
results in genetically unique gametes
• Crossing over -the exchange of chromosome
pieces between homologous chromosomes.
–.
Independent Assortment
• Independent assortment- Chromosomes can
arrange themselves independently during
meiosis.
Cancer
Canceruncontrolled cell
growth that may
have resulted from
mutations affecting
cell cycleregulating proteins
Do you really understand this?
Mitosis and meiosis are processes involved in cellular reproduction. Which of
the following describes and event that results from mitosis but NOT meiosis?
A. two stages of cell division
B. replication of cellular genetic material
C. daughter cells that are identical to the parent cell
D. four daughter cells that are produced from each parent cell
How are sexual reproduction and asexual reproduction different from each
other?
A. sexual reproduction requires two parents and asexual reproduction
requires only one parent
B. asexual reproduction requires two parents and sexual reproduction
requires only one parent
C. mutation rates are lower in sexual reproduction than in asexual
reproduction
D. asexual reproduction occurs only in multicellular organisms
What is the name of this process?
A. meiosis
B. mitosis
C. endocytosis
D. phagocytosis
Which of the following correctly describes the process
being illustrated?
A. mutation in which the DNA content of the gene is
altered
B. segregation of sister chromatids
C. condensation and segregation of alleles
D. crossing-over in which alleles are exchanged