Download Cell Reproduction - South Kingstown High School

Cell Reproduction
http://tbn2.google.com/images?q=tbn:spK6vnBHuv7DlM:http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif
The cell cycle
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Interphase
and Mitosis
DNA replication
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For most of a cells life
chromosome is a single
copy of DNA looking like
Chromatid
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But during the “s” phase of
interphase the chromosome
copies itself making sister
chromatids joined in the
middle by a centromere
Sister Chromatids
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Chromatid
sister chromatids
(because the DNA is copied)
Mitosis
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When a cell go through the phases
Prophase
 Metaphase
 Anaphase
 Telophase
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to make two “daughter” cells that are exactly
identical to the original “parent” cell
Cell parts to know
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Chromosomes: the reason they look like an x
would be because the DNA has been copied.
Each side of the x is a copy of the other.
Spindle fibers: hold chromosomes in an orderly
fashion
Centrioles: in animal cells they hold spindle fibers
and stretch them to opposite sides of cell
Nuclear membrane breaks down and reforms
during the process.
prophase
Interphase
Mitosis: cell
reproduction to make
exact copies of cells
metaphase
anaphase
telophase
2 daughter
cells in
Interphase
http://www.pbs.org/wgbh/nova/miracle/divi_text_03.html
Interphase
“normal” cell not
dividing just doing
its job.
 DNA does
reproduce.
Chromatids form
sister chromatids.

Chromosomes
Nuclear
membrane
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Prophase

Nuclear
membrane
Chromosome
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chromatid
Spindle
fiber
Nuclear membrane
breaks apart
Chromosomes spread
out in cell
Spindle fibers form
stretching from one
side of cell to the other
Animal Cell
Plant Cell
Spindle fibers
Centrioles
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Metaphase
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Chromosomes line up
in center of cell
Held by the spindle
fibers
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Anaphase
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chromatids
Chromosomes split
Sister chromatids
move to opposite ends
of cell
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Telophase

Nuclear
membrane
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2 nuclear membranes
reform around
chromatids
Cell membrane
splitting into two cells
CYTOKINESIS it the
term to describe the
division of the cytoplasm
and it’s contents which
happens when 2 cell
membranes are formed.
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Interphase - again
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cytoplasm
2 new cells
Exact copies with the
same chromosomes of
original cell
http://www.cellsalive.com/mitosis.htm
http://www.youtube.com/watch?v=JHRBJgq50dk
Crazy mitosis song
Drawing are simplified with only 4
chromosomes.
•
•
Human cells have 46 chromosomes
a human skin cell with 46 chromosomes
will make more skin cells with 46
chromosomes by doing mitosis
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Mitosis slides under microscope
Mitosis quiz
Stop motion video or flip book
Cancer

Cancerquest: 11 min cancer overview
http://www.cancerquest.org/cancer-biology-animations.html#
cancer overview from MD Anderson:
http://www.videomd.com/Cancer-what-is-it-fv-791.aspx 6 min
Cancer detection and treatment:
http://video.healthination.com/hn/cancer-treatments/cancersurgery.html
watch cancer surgery, radioation and chemotherapy,
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Website:http://www.insidecancer.org/
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A different type of cell division!
This cell is in the process of
dividing. What are two ways this is
different from mitosis?
• The chromosomes
are lined up in pairs
not single file as in
mitosis–
homologous pairs
• Pieces of the
chromosomes have
traded places –
crossing over
How are the daughter cells
produced at the end different from
mitosis? 4 daughter cells

Parent cell
cell
Parent
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Daughter cells have
half the DNA that the
parent cell has.
The chromosomes
in each of the 4
daughter cells are
different as a result
of crossing over.
Meiosis, What’s the big deal?
• Meiosis is the reason that in
sexually reproducing organisms
• genetic information varies
between parent and offspring,
• Genetic information varies
between offspring from the same
parents.
• Meiosis insures genetic
variation which is essential for
evolution.
• Species genes/traits change
from generation to
generation.
• With a GREAT deal of time
this can produce significant
changes
Meiosis: process to make sex cells
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Daughter cells made from Meiosis are NOT
identical to the “parent” cell.
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Regular body cell 46 chromosomes
Sperm and egg 23 chromosomes
Also crossing over happens where pieces of the
original chromosomes exchange places.
Parent cell
MEIOSIS: to make sex
cells with half the
original DNA.
4 daughter cells
with half of DNA
from parent cell
Homologous chromosomes

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Organisms have pairs of
chromosomes with
corresponding DNA
sequences one from each
parent.
homologous chromosomes are
the same size, their
centromeres are in the same
position, they have the same
number of genes, arranged in
the same order.
Meiosis: CROSSING OVER
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While paired up during prophase I, sections of DNA are
exchanged between homologous chromosomes.
This insures that the chromosomes in sex cells produced are
not identical to the parents chromosomes.
This is one reason each offspring produced by a parent is
unique from any other.
Mitosis vs. Meiosis
Parent cell
Parent cell
2 daughter cells
with identical DNA
to parent cell
2 diploid somatic cells
4 daughter cells
with half of DNA
from parent cell
4 haploid gametes
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http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__comparison_of_meio
sis_and_mitosis__quiz_1_.html animation comparing meiosis and mitosis
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/difficult_multiple_choice.html
questions starting at 15
http://www.sciencegeek.net/Biology/review/U3Review.htm 30 question quiz
http://www.biologycorner.com/quiz/qz_meiosis.html 3 question quiz
http://www.sumanasinc.com/webcontent/animations/content/meiosis.html very good
animation of meiosis
Vocabulary for Bio
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Somatic cell: a body cell that has the organisms
complete diploid set (2N) of chromosomes.
Diploid = 2N: a cell that contains both sets of
homologous chromosomes from the parent.
Gamete: sex cell, sperm or egg cell containing the
haploid (1N) set of chromosomes
Haploid = 1N: a cell containing 1 set of genes
Zygote: fertilized egg 2N
In Humans
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46 chromosomes total
The chromosome you get from your mom and dad
contain similar types of information.
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For example you get genes for eye color from your mom
and genes for eye color from your dad.
The chromosomes can be matched up in pairs
called homologous chromosome pairs.
http://www.miscarriage.com.au/images/pages/karyotype_normal.jpg
Mistakes in meiosis: non-disjunction
Non disjunction: when an error occurs in cell division
* homologous chromosomes do not separate
* Or sister chromosomes do not separate
2 ways nondisjunction can occur
http://warunee.chs.ac.th/c15x11nondisjunction.jpg
Normal
nondisjunction
in Meiosis I
Normal
nondisjunction
in Meiosis II
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A genetic disorder is a disease that
is caused by an abnormality in an
individual's DNA. Abnormalities can range
from a small mutation in a single gene to
the addition or subtraction of an entire
chromosome or set of chromosomes.
(http://learn.genetics.utah.edu/content/disorders/whataregd/)
Disorders
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Most disorders are due to changes within one
chromosome not a change to an entire
chromosome.
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Cystic fibrosis (thick mucus in respiratory system)
Sickle Cell disease (malformed red blood cells that get stuck in capillaries)
Lou Gehrig’s disease/ALS (loss of muscle control)
Due to a change in entire chromosome
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Down’s Syndrome /trisomy 21
Edward’s Syndrome Trisomy 18
Patau syndrome Trisomy 13
Klinefelters syndrome XXY
Turner’s Syndrome XO
XYY
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Trisomy: a third copy of a chromosomes. A
few smaller copies can be tolerated in
humans for example Chromosome 21
results in down syndrome, However most
trisomys are lethal
Monosomies: one missing copy of a
chromosome, a female can survive with
just one X chromosome, however most
monosomies are lethal
Triploid: 2 extra chromosomes this is
always lethal in humans but does exist in
plants
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Mitosis: results in two cells with identical
chromosomes
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Meiosis: results in four cells with different
chromosomes