Download Meiosis Simulation with Pop

Meiosis Simulation with Pop-Beads
Class Set
Instructions
Throughout this activity, you will be completing a simulation of the process of meiosis. Do each successive task
in order, making the requested drawings in your journal (with color), and answer the questions after the
drawings. Letters are things you need to do on the table. Numbers are things that need to be done in your
journal. Illustrations of the pop beads requires that you draw each bead individually. Cell membranes are to be
drawn using the petri dish as a template. You will need to label the following things in each drawing if they are
present: cell membrane, spindle fibers, centrioles, nucleus and centromeres.
Meiosis I
To Simulate Interphase:
A. Construct 1 strand of 10 pop-beads that is all one color. Using another color, construct another strand
that again has 10 pop-beads.
B. Construct a third strand using a color different from the previous 2 strands but this one should only have
6 pop-beads. Now using a 4th color create another strand that is again 6 beads long.
* You should now have 4 strands, each that is a different color, 2 strands should be 10 beads long and
the other 2 should be 6 beads long
C. Draw a circle with your chalk on the counter top and place the chromosomes in the center of the circle
which represents the nucleus. Draw another large circle around that to represent the cell membrane
D. DNA replication occurs, producing a duplicate of each chromosome. Construct identical stands to the
ones you made previously, representing the identical sister chromatids that are created during the Sphase. Each half of the duplicated chromosome is called a chromatid. Join the identical chromatids at
the centromere which is represented by a white pop bead with multiple holes to form a pair of sister
chromatids. You will need to add the centromere bead above the middle of the strands. Repeat for the
all of the chromosomes.
Top of bead
1. What important step happens during the “S” phase of interphase?
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Bottom of bead
Prophase I
In prophase I, homologous chromosomes (chromosomes with the same lengths & genes) move close together
and pair up along their entire length. A tetrad (group of four chromatids) is formed.
A. Form tetrads of your homologous chromosomes (all four chromatids) and entwine them in the center of
the nucleus. Call your teacher over to check.
B. Simulate crossing over by removing a few pop-beads from one area of one homologous chromatid, and
replace with the corresponding pop-beads of the other homologous chromosome. Do this for all pairs of
homologous chromosomes. At the end of this step, all of the sister chromatids should look different and
the nucleus should be removed. Call your teacher over to check
2. Why doesn’t crossing over happen during mitosis?
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Metaphase I
Chromosomes disentangle and become aligned in the center of the cell in homologous pairs.
A. Disentangle your chromosomes, and align the chromosome pairs side by side. In other words, align the
pair of long sister chromatids next to the other pair of long sister chromatids. Do the same with the short
chromosomes. Draw spindle fibers and centrioles.
3. Draw a picture of the chromosomes in metaphase. Drawing should include each pop bead and color.
Example Line Up
Metaphase I
Anaphase I
The homologous chromosomes separate and are drawn to opposite sides of the cell by spindle fibers connected
to centrioles found at opposite ends of the cell.
A. Separate each homologous pair and move one of the long pairs of sister chromatids to one side of the
cell and the other long pair of sister chromatids to the other half of the cell on your table. You are not
breaking apart the paired chromosomes at this time. Do the same with the small chromosomes. Move
the chromosome pairs by the centromeres; noting how the chromosome arms trail the centromere as
movement occurs.
4. Draw a picture of anaphase I. Drawing should include each pop bead and color.
Anaphase I
Telophase I
During meiosis I, cell division occurs resulting in two daughter cells still containing paired chromatids.
A. Create two cellular membranes by erasing the original circle and drawing two circles around the paired
chromosomes. You should also draw a nucleus around the chromosomes of each cell.
5. The sister chromatids of the daughter cell may be different from the sister chromatids in the parent cell.
Why?
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Meiosis II
Prophase II
The chromosomes move toward the center of the daughter cells. Centrioles move to the opposite ends of the
cell.
A. Place the centromeres of the paired strands in the center of each daughter cell. Then remove the nucleus.
6. What occurs in prophase I that doesn’t happen in prophase II of meiosis?
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Metaphase II
All of the chromosomes line up, single file, in the center of the cell.
A. Center the pair strands along an imaginary line across the center of the cell.
Example Line Up
7. Draw a picture of metaphase II. Drawing should include each pop bead and color.
Daughter Cell 1: Metaphase II
Daughter Cell 2: Metaphase II
Anaphase II
The chromosomes of each paired strand separate at the centromere and are drawn to opposite poles of the cell.
A. Separate each paired chromatid by breaking the centromere and move each strand toward its respective
centrioles, noting how the chromosome arms trail the centromere as it moves towards each pole. Repeat
this procedure for both daughter cells.
8. Draw a picture of anaphase II. Drawing should include each pop bead and color.
Daughter Cell 1: Anaphase II
Daughter Cell 2: Anaphase II
Telophase II and Cytokinesis
Cell division is completed and four daughter cells are formed. Each contains half of the chromosome number
of the original parent cell. A nuclear membrane forms around each cell’s chromosomes and the daughter cells,
from Meiosis I, finish dividing completely.
A. Erase the original 2 circles and draw four circles to represent each of the new cells. Then draw a circle
around each of the chromosome sets inside the new cells to represent the nucleus of the each cell.
9. Draw a picture of the cells after telophase II & cytokinesis. Drawing should include each pop bead and
color.
Daughter Cell 1
Daughter Cell 2
Daughter Cell 3
Daughter Cell 4
10. It would have been much easier to simulate mitosis. Give two ways the process of meiosis differs from
mitosis.
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