Modeling Mitosis and Meiosis
Biology AP 2013
Objective: To use a model to simulate the processes of Mitosis and Meiosis
Materials: 34 red pop beads, 34 yellow pop beads, plastic centromeres, 2 clear plastic centrioles
Part 1– PROCEDURE: Modeling Mitosis
To simulate Interphase – DNA replication:
1. Construct one strand of seven red pop beads (3 on one side of the centromere and 4 on
the other) and one strand of ten red pop beads (5 on each side of the centromere).
Repeat with one strand of seven yellow pop beads and one strand of ten yellow pop
beads. These will represent two pairs of homologous chromosomes (red from the father
and yellow from the mother).
2. Designate an area on the lab table to be the nucleus of your cell. Place your
chromosomes in the nucleus.
3. During interphase DNA replication occurs, producing a duplicate of each chromosome.
Construct four chromosomes identical to the ones you made previously. Each of the
duplicated chromosomes is called a chromatid. Join the long red chromatids in the
middle to form a pair of sister chromatids. Repeat this process for the yellow long, red
short, and yellow short chromosomes. You now have 4 duplicated chromosomes. Make
sure you attach the red chromatids together and the yellow chromatids together, not
one red attached to one yellow chromatid
4. Place a pair of plastic centrioles, at a ninety degree angle, just outside of your nuclear
membrane.
5. Make a colored drawing of your simulation of interphase and in your own words provide
a brief description of what happens during interphase.
To simulate Prophase:
1. Move your two centrioles to opposite poles (sides) of the cell (your lab table).
2. Draw your simulation of prophase and in your own words provide a brief description of
what happens during prophase.
To simulate Metaphase:
1. Center your chromosomes along an imaginary metaphase plate with the centrioles still at
the opposite poles of the cells.
2. Draw your simulation of metaphase and in your own words provide a brief description of
what happens during metaphase.
To simulate Anaphase:
1. Separate the centromeres of each chromosome and move the chromosomes toward
opposite poles of the cell. Notice how the arm of each chromosome trails the centromeres
to the poles.
2. Draw your simulation of anaphase and in your own words provide a brief description of
what happens during anaphase.
To simulate Telophase and Cytokinesis:
1. Move both red strands and both yellow strands to the centrioles they were heading toward
during anaphase. Imagine a cleavage furrow developing between each nuclei and
separating the cell into two daughter cells.
2. Note how each cell now contains two red and two yellow chromosomes, as well as one pair
of centrioles, exactly like the cell with which you began.
3. Draw your simulation of telophase/cytokinesis and in your own words provide a brief
description of what happens during telophase/cytokinesis.
Part 2 – PROCEDURE: Modeling Meiosis
Meiosis 1—The goal of meiosis 1 is to separate the homologous chromosomes from each other and
create haploid cells.
To simulate Prophase of Meiosis 1:
1. Rebuild your red and yellow chromosomes so they look like they did during prophase of mitosis.
2. Arrange your chromosomes into homologous pairs. Draw the arrangement of your
chromosomes. In your own words provide a brief description of what happens during this
phase.
3. Simulate crossing over between 2 of the non-sister chromosomes. Draw the results. In your
own words provide a brief description of what happens during this process.
To simulate Metaphase 1:
4. Center your chromosomes along an imaginary metaphase plate with the centrioles still at
the opposite poles of the cells. Arrange your chromosomes with both red ones on one side
of the cell and both yellow ones on the other.
5. Draw your simulation of metaphase and in your own words provide a brief description of
what happens during metaphase
To simulate Anaphase 1:
1. Separate the homologous pairs of chromosomes and move them towards the opposite
poles of the cell. Be sure to leave the centromere attached to both sister chromatids.
2. Draw your simulation of metaphase and in your own words provide a brief description of
what happens during anaphase.
To simulate Telophase 1 and Cytokinesis:
1. Move both red strands and both yellow strands to the centrioles they were heading toward
during anaphase. Imagine a cleavage furrow developing between each nuclei and separating
the cell into two daughter cells.
2. Draw your simulation of telophase 1/cytokinesis and in your own words provide a brief
description of what happens during these phases.
Meiosis 2—The goal of Meiosis 2 is to separate the sister chromatids from each other to create the
haploid gamete cells.
To simulate Meiosis 2 follow the instructions in the mitosis section, but keep each “cell’s”
chromosomes separate from each other. You should produce 4 haploid daughter cells at the end of
the simulation. Draw and describe each step as you move the chromosomes.
Alternate arrangement of chromosomes:
The assortment of chromosomes into the gametes ultimately depends on how the homologous
pairs line up during Meiosis 1. To simulate this, repeat the steps of meiosis, but this time have one
red and one yellow chromosome line up on the same side of the cell during Metaphase 1. Model
the steps of meiosis and draw the arrangement of the chromosomes at each stage through the end
of meiosis 2.
Analysis Questions:
1. How does mitosis lead to the formation of 2 daughter cells each of which are diploid and
genetically identical to the original cell?
2. What is the role of the centriole in cell division?
3. List 3 major differences between the events of mitosis and meiosis.
4. How are meiosis 1 and meiosis 2 different?
5. Why is meiosis necessary for sexual reproduction?
6. Complete the table
Mitosis
Meiosis
Chromosome number in
parent cell (n or 2n)
# of DNA replications
# of divisions
# of daughter cells produced
Chromosome # of daughter
cells
Purpose/function