Mitosis and Meiosis made Simple.
Mitosis and Meiosis
Cell Division, Asexual Reproduction, and Mitosis
Multicellular living things grow and repair their ___________. Your skin
cells are always dying, losing 30 to 40 thousand every minute, and
being replaced. We humans lose cells but our epidermis works to make
____________ skin cells to replace the dead cells. Where do new skin
cells come from? They are made when existing cells divide to form new
cells that are exactly _____________. This process is called cell division.
The original cell that divides is called the ________________ cell.
The cells formed through cell division are called ______________ cells.
In mitosis you obtain ________ genetically identical daughter cells from
_________ parent cell.
Vocabulary:
Homologous - Pairs of chromosomes that have ________________ for
the same traits arranged in the same order. The chromosomes may not
be identical because each one of the pairs is inherited from a
different____________. The father may have the gene for brown hair
while the mother might have the gene for blonde hair on the
homologous pair of___________________. The genes for hair color
from the mother and father would be on the same ___________on the
chromosome.
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Sister Chromatids - are two identical halves of a single replicated
(copied) ________________ that are connected by an area called a
centromere. They are joined at the centromere (see diagram) and are
genetically identical.
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A chromosome made up of two sister chromatids
held together at the centromere.
http://www.macroevolution.net/meiosis-stages.html#.UYAtjWzD-EV
Centromere - A centromere is a region on a __________________ that
joins two sister chromatids.
Diploid cells – Cells that have _____________ of chromosomes. In
humans we have 23 pairs of chromosomes for a total of _____
chromosomes.
Haploid cells – are cells that have only ______ chromosome from each
pair. In humans these would be the ________ and sperm _________
which would have 23 chromosomes each.
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Asexual Reproduction: Asexual reproduction is the reproduction of one
cell from one _______________. The process of mitosis is used to
produce exact ________________ cells from the parent cell in simple
organisms that have a nucleus (eukaryotes). The process called Binary
Fission occurs when a simple organism divides in half to make two
new_____________. This method occurs in unicellular (one cell)
organisms and is the main type of reproduction in the Protista
Kingdom. Examples are algae, paramecium, amoeba, and euglena.
The parent cell is exactly ____________ or genetically the same as the
two new _______________ cells. In the process of binary fission, an
organism duplicates its genetic material, or _______________ and then
divides into two parts (cytokinesis), with each new organism receiving
one ___________ of the chromosomes that carry the DNA.
Cytokinesis, in biology, is the process by which one cell physically
divides into _______ cells.
Another type of asexual reproduction called regeneration occurs when
an organism grows from a part of its_____________. The ability to
regenerate a new organism varies greatly among animals. An example
is some sea __________________ have five arms. If separated from the
parent each arm has the potential to ________________into a new
starfish if the arm contains a part of the central disc. Like all asexual
reproduction, the offspring is genetically _________________to the
parent.
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Before a eukaryotic cell (a cell with a true nucleus) divides, the genetic
material in the nucleus of the cell _______________itself. When the
cell divides, the nuclear material splits in half so that each daughter cell
gets genetic material that is the ___________ as that of the parent cell.
The dividing of the nuclear material is known as mitosis. In the last
stage of cell division, the cytoplasm that makes up the cell also divides.
The cytoplasm consists of all of the contents outside of the
________________ and enclosed within the cell membrane of the cell.
There are now _____________ complete cells where there used to be
one.
Cell division is the complete process of dividing the whole ________
called cytokinesis and dividing and copying of the nuclear material
called mitosis.
A simple explanation of what takes place in Mitosis
1. (Interphase) Before mitosis takes place the cell performs all its
normal functions or_____________. Different cells will go
through the process of mitosis at different times of their lives
depending on what type of ___________ it is. For an example
nerve cells may take up to over 60 years before they begin the
process of mitosis while ____________ cells may take from 20
to 24 hours. http://www.usatoday.com/videos/news/health/2014/04/08/7452193/ (man walks damaged n)
(Interphase part 2) Just before the beginning of mitosis the
DNA in the nucleus makes an exact ____________ of itself and
the cell replicates its chromosomes. Each chromosome is
composed of two sister chromatids containing
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______________ genetic information. The cell is now ready for
mitosis. The process of mitosis usually takes about an hour to
complete.
Two sister chromatid which is also called a
__________________________.
2. (Prophase) Early during prophase, the first stage of mitosis, the
chromosomes become visible with a light microscope as they
condense (that is, as they shorten, coil, and thicken).The
______________ wall of the cell disappears and the
chromosome copies are held together at their centers, so they
form a sort of X. The center where the two identical chromatids
meet is called the__________________. These chromosomes
are called sister chromatids. Also, spindle fibers begins to
extend outward from each of the two centrioles. Finally the
spinal fibers from both sides of the cell attach themselves to
the ____________________ (area where the two
_____________________ are attached).
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3. (Metaphase) The chromosome or sister
____________________ pairs line up single file at the center of
the _________.
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4. (Anaphase) Now, during anaphase, the two sister chromatids
of each chromosome are pulled _____________ by the spindle
fibers and dragged by their centrosomes toward opposite poles
of the _______________.
5. (Telophase) During telophase (pronounced "TEE-low-faze" or
"TELL-ə-faze"), the last stage of mitosis, the chromosomes have
reached the opposite ends of the ______________ and they
begin to uncoil and become less condensed (reversing the
process that occurred during prophase. A new nuclear
membrane is produced surrounding the _________________.
Also cytokinesis occurs during this stage as the cytoplasm
pinches in at the center of the cell, dividing the original cell in
________________. Cytokinesis is not a part of ____________
but can start to occur in the last stage of anaphase into the
telophase.
http://www.macroevolution.net/mitosisanimation.html#.UYfQBV_D8dU – Mitosis video Use to show
meiosis go to bottom biological dictionary – look up Meiosis –
go to next page at bottom and then go to meiosis animation.
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6. The cell division is complete two _______________ daughter
cells are formed which is identical to the original
_______________cell. The two new daughter cells then would
grow and carry on their function or __________. In humans
you will produce two ________________daughter cells with 46
chromosomes or ______ homologous pairs.
Meiosis
The beginning of Meiosis is very similar to _____________ with
some very important differences. The job of meiosis is to
produce 4 daughter cells or gametes (sex cells) with half the
number of chromosomes (_______________ number) from
one parent cell (____________ number).
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A simple explanation of what takes place in Meiosis
Meiosis part 1

(Interphase) This also is not a true step in__________________. Just
before the beginning of meiosis the DNA in the nucleus makes an
exact ____________ of itself and the cell replicates its
chromosomes. Each chromosome is composed of two sister
chromatids containing _________________ genetic information. The
cell is now ready for meiosis.
Steps in Meiosis
1. (Prophase I) Nearly the same as mitosis as the cell wall of the
____________ disappears and homologous chromosomes
come together matching gene by____________. The matching
homologous chromosomes from the
________________(maternal) and _____________(paternal)
pair up. This gives us two chromosomes or two
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_________________ chromosomes or two pairs of sister
________________ which are paired up. The mothers’
homologous pair and the fathers’ homologous pair have the
same _____________ information. Example: eye color - one
gene on the chromosome may have a different trait for eye
color than the other one or they may have the same trait for
eye color. The father may have a gene for the trait of brown
eyes while the mother may have the trait for blue eyes or they
both might have the gene that would produce blue eyes. The
sister chromatids are held together at their centers forming an
X; the center is called a centromere.
Figure 1 4 chromosomes or two homologous pairs with the beginning
of spinal fibers forming from the centrioles.
2. (Prophase I) During this phase the paired up chromosomes or
the two pair of sister chromatids from the _____________ and
_______________can swap matching sections of the
chromosome material called cross over. This process called
cross over increases genetic diversity where every
chromosome and the two pair of sister chromatids are
genetically __________________. No crossing over occurs
between two sister chromatids but between the two pair of
sister chromatids from the _______________ and
_______________.
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Every gamete or chromosome is genetically different
3. (Metaphase I) The homologous chromosomes or the two pairs
of ____________ ______________ line up in pairs along the
center of the __________: this is different from mitosis in
which the chromatids lined up ______________ file. Then
special apparatus called a _______________ fiber organized
from centrioles attaches itself to the center of the sister
chromatids (_____________________) and during the next
phase each pair of sister chromatids are pulled to
_______________ sides of the cell.
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4. (Anaphase I) Almost the same as in mitosis as the homologous
paired chromosomes or sister chromatids ____________ from
each other as they move to opposite sides of the cell. The
chromosomes or two sister chromatids from the
_______________ or ____________ can go to either side of
the dividing cell. This is different than mitosis because in
mitosis the sister chromatids separate into ________ parts and
go to _________________ sides of the cell while in meiosis the
sister chromatids do __________ separate.
5. (Telophase I) At each pole, now, there is a complete set of
homologous chromosomes (but each chromosome still has
sister chromatids).During this stage cytokinesis occurs as the
cytoplasm pinches in at the ____________ of the cell, dividing
the original cell in______________. The cytoplasm pinches in
at the center of the _________ , dividing the original parent
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cell in ___________ producing two ________________
daughter cells. The sister chromatids or chromosomes do not
________________ but stay attached at the centromeres. Two
haploid daughter cells form with different _________________
materials.
Meiosis part 2
6. (Prophase II) If a nuclear membrane formed around the
chromosomes than the nuclear membrane breaks
_____________ but the chromosomes are not copied. Again,
the chromosomes are not yet attached to the spindle
apparatus, which is growing outward from the centrioles.
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7. (Metaphase II) For each daughter cell the homologous
chromosomes or sister chromatids again line up in the
_____________ of the cell but this time single-file instead of
pairs. The ______________ fibers attach themselves to
opposite ends of the ________________ of each chromatid.
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8. (Anaphase II) During anaphase II the sister chromatids of each
chromosome ______________ and move toward
________________ poles. Once they are no longer connected,
the former chromatids are called unreplicated chromosomes.
One chromosome is pulled to one _____________ of the cell.
The other chromosome is pulled to the other side of the cell.
9. (Telophase II) During telophase II, the _________________
reach opposite poles, cytokinesis occurs, the two cells
produced by meiosis I divide to form _________ haploid
________________ cells. When the two cells are entirely
separated and the ___________ around the chromosomes is
fully formed, meiosis will be complete.
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http://www.macroevolution.net/meiosisanimation.html#.UYfp7WzD-EU Use to show meiosis go to
bottom biological dictionary – look up Meiosis – go to next
page at bottom and then go to meiosis animation.
10. Four new ________________ cells have formed from the
original cell. Each of the four cells has half the number of
chromosomes that the original cell had, and therefore only half
the amount of ______________ material. Each one of the cells
is not exactly __________ but has some different genetic
material. It creates diversity which is essential for the
development and survival of the species.
11. The final product of meiosis is the production of 4 daughter
_________________ sex cells called gametes that are
genetically different from one diploid parent cell. The
___________ gametes are called sperm and the
______________ gametes are called eggs. In humans from one
diploid cell with _______ chromosomes or ______ homologous
pairs produce four daughter cells with __ chromosomes.
12. When a female _______(23 chromosomes - haploid number)
is fertilized with a male sperm (_____chromosomes ___________number) the fertilized egg called a zygote will
again have the ______________ number of chromosomes 46.
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Half of chromosomes from the __________ (23) and half the
chromosomes (23) from the__________. Each chromosome
from each parent has a matching pair called a
________________ pair where the same genes are located for
the same characteristics. In humans we have _____
homologous pairs. See Vocabulary.
https://www.youtube.com/watc
h?v=toWK0fIyFlY great meiosis
show cartoon
http://www.youtube.com/watch
?v=gwcwSZIfKlM great mitosis
show video
Above diagram shows the
steps in meiosis
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http://highered.mcgrawhill.com/sites/9834092339/student_view0/chapter29/mitosis.html
http://www.youtube.com/watch?v=35ncSrJOwME&feature=related
http://highered.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/007
2437316/120074/bio19.swf::Stages%20of%20Meiosis
http://sumanasinc.com/webcontent/animations/biology.html
http://www.macroevolution.net/prophase-i.html#.UXmbkGzD-EU One
used for notes
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Mitosis and Meiosis Compared
It's really important that you don't get meiosis and mitosis confused! Take some
time to look at the table below and make sure you understand all the differences
between the two types of cell division.
Mitosis
Meiosis
Purpose
To make daughter cells
_______________ to the
To produce sex cells (gametes or
parent cells during
eggs and sperm)
growth, repair, or for
asexual reproduction.
Location
In all cells apart from
________________
In the _____________ organs
(ovaries - female and testes- male)
Produces how
many cells?
Two _____________
cells
____________ gametes or daughter
cells (sex cells – eggs or sperm cells)
Same number as in
What happens to
_______________ cell
number of
which is the diploid
chromosomes?
number.
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_______________ as many as in
parent cell. When you have half of
the genetic material and
chromosomes it is called a
_________________ cell. (The
original number of chromosomes is
restored when two
________________ fuse to form a
zygote which is a fertilized egg cell.
This will produce a
_________________ cell with
genetically matching chromosome
from ________ and genetically
matching chromosome from
_______ called homologous pairs.)
Mitosis
Meiosis
How do parent
and daughter
cells differ
genetically?
Not at all - genetic
Contain a mixture of chromosomes
material is ___________ from two parent gametes - so
exactly (replicated)
cannot be ___________
Variation
between
daughter cells?
________ - they are
clones of each other
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____________ - they are genetically
________________ from each
other.
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