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Comparing Mitosis and Meiosis
The body carries out two types of cell division. Mitosis results in the formation of new body cells,
called somatic cells. The cells that are formed by mitosis are genetically the same as each other and the
same as the parent cell.
Somatic cells contain chromosomes in pairs called homologues. Homologous chromosomes carry
alleles for the same traits, but are not identical to one another. Each pair of homologous chromosomes is
made up of one chromosome inherited from the mother, and the other from the father. Since somatic cells
have pairs of chromosomes, they are described as being diploid cells.
Meiosis results in the formation of reproductive cells called gametes. Gametes have one
homologue of each pair found in the somatic cells; meiosis accomplishes the task of dividing the amount
of DNA contained by the cell in half. Since they have a single copy of each type of chromosome, gametes
are described as being haploid cells.
At fertilization, haploid gametes fuse to create a diploid zygote. The developing offspring grows as
somatic cells are produced through the process of mitosis.
What You Will Do
a) Model cell division processes.
b) Compare the process of mitosis with the process of meiosis.
c) Create diagrams of mitosis and meiosis to show the results of these processes.
Materials
cell templates
ruler
colored pencils or markers
4 pieces of yarn, 4 different colors
scissors
Prepare your materials
Using the first color of yarn, cut two pieces 1.5 cm long.
Cut two pieces of a second color 1.5 cm long.
Using a third color, cut two pieces 2.5 cm long.
Cut two pieces of a fourth color 2.5 cm long.
Part A: Mitosis
• Use diagrams A, B, and C for this part of the activity. Place them on the table, one below the other
in the proper order.
• Diagram A represents the parent cell during interphase. Place two long pieces of yarn of different
colors and two short pieces of yarn of different colors in the cell. These are the four chromosomes
contained in the parent cell. There are two homologous pairs: the two long chromosomes make up
one pair, the two short chromosomes are another pair. Note that the paired chromosomes are not
identical.
• Draw the chromosomes in cell A at the top of the mitosis column.
Before the cell begins mitosis, chromosomes are copied using a process called replication.
• To show DNA replication, match new pieces of yarn identical to those in the parent cell. The
matched pieces of yarn represent sister chromatids.
• Draw the chromosomes in cell A as they now appear.
During mitosis, sister chromatids line up in the center of the cell.
• Transfer the chromosomes to diagram B and position them within the dashed outlines.
• Draw the chromosomes in cell B.
• Anaphase separates sister chromatids. Move the chromosomes that are lined up on the left to the
left. Move the chromosomes on the right to the right side of the cell.
• Draw the chromosomes in cell B as they appear now.
Once the chromosomes separate, the cell pinches in half to form two new cells.
• Move the chromosomes on the left side of diagram B to the left cell of diagram C, and those on the
right side of B to the right cell of diagram C.
• Draw the chromosomes in the C cells.
Part B: Meiosis
• Use diagrams D, E, F and G for this part of the activity. Place them on the table, one below the
other in the proper order.
• Diagram D represents the parent cell before meiosis begins. Place two long pieces of yarn of different
colors and two short pieces of yarn of different colors in the cell. These are the four chromosomes
contained in the parent cell. Note that this cell is the same as the parent cell in part A.
• Draw the chromosomes in cell D at the top of the meiosis column.
Before the cell begins meiosis, DNA replication occurs.
• To show replication, match new pieces of yarn identical to those in the cell to represent sister
chromatids.
• Draw the chromosomes in cell D as they appear now below the first sketch.
Sister chromatids line up in the center of the cell in homologous pairs. These groups of chromosomes are
called tetrads.
• Transfer the chromosomes to diagram E and position them within the dashed outlines.
• Draw the chromosomes in cell E.
• Anaphase I separates homologous chromosomes, but the sister chromatids do not split. Move the
sister chromatids that are lined up on the left to the left. Move the chromatids on the right to the
right side of the cell.
• Draw the chromosomes in cell E as they appear now.
Once the homologous chromosomes separate, the cell pinches in half to form two new cells.
• Move the sister chromatids on the left side of diagram E to the left cell of diagram F, and the sister
chromatids on the right side of E to the right cell of diagram F.
• Draw the chromosomes in the F cells.
Sister chromatids line up in the center of each cell, the centromeres now break, and the chromosome
copies separate.
• Move the chromosomes that are lined up on the left to the left of the cells in diagram F. Move the
chromosomes on the right to the right side of the cells.
• Draw the chromosomes in the F cells as they appear now.
The two cells pinch in half to form two new cells each for a total of four cells.
• Move the chromosomes on the left side of diagram F to the left cells of diagram G, and those on the
right side of F to the right cells of diagram G.
• Draw the chromosomes in the G cells.
Part C: Analysis
Complete Table 1 on the handout.
Answer the following on a separate sheet of notebook paper.
Describe patterns that would be correct for any organism’s cells, not just the example cells in the
diagram.
1. Compare the chromosomes of a parent cell for mitosis to the chromosomes of a parent cell for
meiosis.
2. Compare the chromosomes of one daughter cell produced by mitosis to those of a parent cell.
3. Describe how the chromosomes in one meiosis daughter cell are different than the chromosomes of
a parent cell.
4. Examine metaphase of mitosis and metaphase I of meiosis. What do they have in common? How
does the arrangement of chromosomes differ?
5. Examine the chromosomes in metaphase of mitosis and in one cell of metaphase II of meiosis.
What is similar? How do they differ?
6. Describe the similarities and differences between the chromosomes found in the four daughter cells
produced by meiosis. Remember that in real cells, crossing over occurs during prophase I.
Complete Table 2 and Table 3 on the handout.