Experiment 2: The Importance of Cell Cycle Control Some environmental factors can cause genetic mutations which result in a lack of proper cell cycle control (mitosis). When this happens, the possibility for uncontrolled cell growth occurs. In some instances, uncontrolled growth can lead to tumors, which are often associated with cancer, or other biological diseases. In this experiment, you will review some of the karyotypic differences which can be observed when comparing normal, controlled cell growth and abnormal, uncontrolled cell growth. A karyotype is an image of the complete set of diploid chromosomes in a single cell. Materials *Computer Access *Internet Access *You Must Provide Procedure 1. Begin by constructing a hypothesis to explain what differences you might observe when comparing the karyotypes of human cells which experience normal cell cycle control versus cancerous cells (which experience abnormal, or a lack of, cell cycle control). Record your hypothesis in Post-Lab Question 1. Note: Be sure to include what you expect to observe, and why you think you will observe these features. Think about what you know about cancerous cell growth to help construct this information 2. Go online to find some images of abnormal karyotypes, and normal karyotypes. The best results will come from search terms such as “abnormal karyotype”, “HeLa cells”, “normal karyotype”, “abnormal chromosomes”, etc. Be sure to use dependable resources which have been peer-reviewed 3. Identify at least five abnormalities in the abnormal images. Then, list and draw each image in the Data section at the end of this experiment. Do these abnormalities agree with your original hypothesis? Hint: It may be helpful to count the number of chromosomes, count the number of pairs, compare the sizes of homologous chromosomes, look for any missing or additional genetic markers/flags, etc. 4. Take a picture of your results. Include a note with your name and date on an index card in the picture. Insert picture here. Data 1.   2.   3.   4.   5.   Experiment 1: Following Chromosomal DNA Movement through Meiosis In this experiment, you will model the movement of the chromosomes through meiosis I and II to create gametes. Materials 2 Sets of Different Colored Pop-it® Beads (32 of each - these may be any color) 8 5-Holed Pop-it® Beads (used as centromeres) Procedure: Part 1: Modeling Meiosis without Crossing Over As prophase I begins, the replicated chromosomes coil and condense… 1. Build a pair of replicated, homologous chromosomes (Figure 3). 10 beads should be used to create each individual sister chromatid (20 beads per chromosome pair). Two five-holed beads represent each centromere. To do this... Figure 3:Bead set-up. The blue beads represent one pair of sister chromatids and the black beads represent a second pair of sister chromatids. The black and blue pair are homologous. a. Start with 20 beads of the same color to create your first sister chrom ...

1. Experiment 2: The Importance of Cell Cycle Control
Some environmental factors can cause genetic mutations which
result in a lack of proper cell cycle control (mitosis). When this
happens, the possibility for uncontrolled cell growth occurs. In
some instances, uncontrolled growth can lead to tumors, which
are often associated with cancer, or other biological diseases.
In this experiment, you will review some of the karyotypic
differences which can be observed when comparing normal,
controlled cell growth and abnormal, uncontrolled cell growth.
A karyotype is an image of the complete set of diploid
chromosomes in a single cell.
Materials
*Computer Access
*Internet Access
*You Must Provide
Procedure
1. Begin by constructing a hypothesis to explain what
differences you might observe when comparing the karyotypes
of human cells which experience normal cell cycle control
versus cancerous cells (which experience abnormal, or a lack of,
cell cycle control). Record your hypothesis in Post-Lab
Question 1.
Note: Be sure to include what you expect to observe, and why

2. you think you will observe these features. Think about what you
know about cancerous cell growth to help construct this
information
2. Go online to find some images of abnormal karyotypes, and
normal karyotypes. The best results will come from search
terms such as “abnormal karyotype”, “HeLa cells”, “normal
karyotype”, “abnormal chromosomes”, etc. Be sure to use
dependable resources which have been peer-reviewed
3. Identify at least five abnormalities in the abnormal images.
Then, list and draw each image in the Data section at the end of
this experiment. Do these abnormalities agree with your original
hypothesis?
Hint: It may be helpful to count the number of chromosomes,
count the number of pairs, compare the sizes of homologous
chromosomes, look for any missing or additional genetic
markers/flags, etc.
4. Take a picture of your results. Include a note with your name
and date on an index card in the picture. Insert picture here.
Data
1.
2.
3.
4.
5.
Experiment 1: Following Chromosomal DNA Movement through
Meiosis
In this experiment, you will model the movement of the
chromosomes through meiosis I and II to create gametes.
Materials
2 Sets of Different Colored Pop-it® Beads (32 of each - these
may be any color)
8 5-Holed Pop-it® Beads (used as centromeres)

3. Procedure:
Part 1: Modeling Meiosis without Crossing Over
As prophase I begins, the replicated chromosomes coil and
condense…
1. Build a pair of replicated, homologous chromosomes (Figure
3). 10 beads should be used to create each individual sister
chromatid (20 beads per chromosome pair). Two five-holed
beads represent each centromere. To do this...
Figure 3:Bead set-up. The blue beads represent one pair of
sister chromatids and the black beads represent a second pair of
sister chromatids. The black and blue pair are homologous.
a. Start with 20 beads of the same color to create your first
sister chromatid pair. Five beads must be snapped together for
each of the four different strands. Two strands create the first
chromatid, and two strands create the second chromatid with a
5-holed bead at the center of each chromatid. This creates an
“I” shape.
b. Connect the “I” shaped sister chromatids by the 5-holed
beads to create an “X” shape.
c. Repeat this process using 20 new beads (of a different color)
to create the second sister chromatid pair.
2. Assemble a second pair of replicated sister chromatids
(Figure 4); this time using 12 beads, instead of 20, per pair (six
beads per each complete sister chromatid strand).
Figure 4:Second set of replicated chromosomes.
3. Pair up the homologous chromosome pairs created in Step 1
and 2. DO NOT SIMULATE CROSSING OVER IN THIS
TRIAL. You will simulate crossing over in Part 2.

4. 4. Configure the chromosomes as they would appear in each of
the stages of meiotic division (prophase I and II, metaphase I
and II, anaphase I and II, telophase I and II, and cytokinesis).
5. Diagram the corresponding images for each stage in the
sections titled “Trial 1 - Meiotic Division Beads Diagram”. Be
sure to indicate the number of chromosomes present in each cell
for each phase.
6. Take a picture of your results. Include a note with your name
and date on an index card in the picture. Insert picture here.
Part 1 - Meiotic Division Beads Diagram
Prophase I
Metaphase I
Anaphase I
Telophase I
Prophase II
Metaphase II
Anaphase II
Telophase II
Cytokinesis
7. Disassemble the beads used in Part 1. You will need to
recycle these beads for a second meiosis trial in Steps 8 - 13.
Part 2: Modeling Meiosis with Crossing Over
7. Build a pair of replicated, homologous chromosomes. 10
beads should be used to create each individual sister chromatid
(20 beads per chromosome pair). Two five-holed beads
represent each centromere. To do this...
a. Start with 20 beads of the same color to create your first
sister chromatid pair. Five beads must be snapped together for

5. each of the four different strands. Two strands create the first
chromatid, and two strands create the second chromatid with a
5-holed bead at the center of each chromatid. This creates an
“I” shape.
b. Connect the “I” shaped sister chromatids by the 5-holed
beads to create an “X” shape.
c. Repeat this process using 20 new beads (of a different color)
to create the second sister chromatid pair.
8. Assemble a second pair of replicated sister chromatids; this
time using 12 beads, instead of 20, per pair (six beads per each
complete sister chromatid strand). Snap each of the four pieces
into a new five-holed bead to complete the set up.
9. Pair up the homologous chromosomes created in Step 8 and
9.
10. SIMULATE CROSSING OVER. To do this, bring the two
homologous pairs of sister chromatids together (creating the
chiasma) and exchange an equal number of beads between the
two. This will result in chromatids of the same original length,
there will now be new combinations of chromatid colors.
11. Configure the chromosomes as they would appear in each of
the stages of meiotic division (prophase I and II, metaphase I
and II, anaphase I and II, telophase I and II, and cytokinesis).
12. Diagram the corresponding images for each stage in the
section titled “Trial 2 - Meiotic Division Beads Diagram”. Be
sure to indicate the number of chromosomes present in each cell
for each phase. Also, indicate how the crossing over affected
the genetic content in the gametes from Part1 versus Part 2.
13. Take a picture of your results. Include a note with your
name and date on an index card in the picture. Insert picture
here.
Part 2 - Meiotic Division Beads Diagram:
Prophase I
Metaphase I
Anaphase I

6. Telophase I
Prophase II
Metaphase II
Anaphase II
Telophase II
Cytokinesis
Your Full Name: UMUC Biology 102/103Lab 5:
MeiosisINSTRUCTIONS:
· On your own and without assistance, complete this Lab 5
Answer Sheet electronically and submit it via the Assignments
Folder by the date listed in the Course Schedule (under
Syllabus).· To conduct your laboratory exercises, use the
Laboratory Manual located under Course Content. Read the
introduction and the directions for each exercise/experiment
carefully before completing the exercises/experiments and
answering the questions. · Save your Lab 5 Answer Sheet in the
following format: LastName_Lab5 (e.g., Smith_Lab5).· You
should submit your document as a Word (.doc or .docx) or Rich
Text Format (.rtf) file for best compatibility.
Pre-Lab Questions
1. Compare and contrast mitosis and meiosis.
2. What major event occurs during interphase?

7. Experiment 1: Following Chromosomal DNA Movement through
Meiosis
Data Tables and Post-Lab AssessmentTrial 1 - Meiotic Division
Without Crossing Over Beads Diagram:
Take pictures of your beads for each phase of meiosis I and II
without crossing over. Include notes with your name, date and
meiotic stage on index cards in the pictures. Please use the
lowest resolution possible so that your file does not become too
large to submit.Insert pictures here:
Prophase I
Metaphase I
Anaphase I
Telophase I
Prophase II
Metaphase II
Anaphase II
Telophase I
Cytokinesis
Trial 2 - Meiotic Division with Crossing Over Beads
Diagram:Take pictures of your beads for each phase of meiosis I
and II with crossing over. Include notes with your name, date
and meiotic stage on index cards in the pictures. Please use the
lowest resolution possible so that your file does not become too
large to submit.Insert pictures here:
Prophase I
Metaphase I
Anaphase I
Telophase I
Prophase II
Metaphase II
Anaphase II
Telophase I
Cytokinesis

8. Post-Lab Questions
1. What is the ploidy of the DNA at the end of meiosis I? What
about at the end of meiosis II?
2. How are meiosis I and meiosis II different?
3. Why do you use non-sister chromatids to demonstrate
crossing over?
4. What combinations of alleles could result from a crossover
between BD and bd chromosomes?
5. How many chromosomes were present when meiosis I
started?
6. How many nuclei are present at the end of meiosis II? How
many chromosomes are in each?
7. Identify two ways that meiosis contributes to genetic
recombination.

9. 8. Why is it necessary to reduce the number of chromosomes in
gametes, but not in other cells?
9. Blue whales have 44 chromosomes in every cell. Determine
how many chromosomes you would expect to find in the
following:
i. Sperm Cell:
ii. Egg Cell:
iii. Daughter Cell from Mitosis:
iv. Daughter Cell from Meiosis II:
10. Research and find a disease that is caused by chromosomal
mutations. When does the mutation occur? What chromosomes
are affected? What are the consequences?
11. Diagram what would happen if sexual reproduction took
place for four generations using diploid (2n) cells.
Experiment 2: The Importance of Cell Cycle Control
For each of the five abnormalities you find online, copy and
paste a picture of it (and be sure to cite the URL for the
picture)—you will not be photographing your own results for
this section of lab, because you’re doing your research online
for the questions below.
Data Tables and Post-Lab Assessment
1. [paste in your online picture and cite the URL]

10. 2. [paste in your online picture and cite the URL]
3. [paste in your online picture and cite the URL]
4. [paste in your online picture and cite the URL]
5. [paste in your online picture and cite the URL]
Post-Lab Questions
1. Record your hypothesis from Step 1 in the Procedure section
here.
2. What do your results indicate about cell cycle control?
3. Suppose a person developed a mutation in a somatic cell
which diminishes the performance of the body’s natural cell
cycle control proteins. This mutation resulted in cancer, but was
effectively treated with a cocktail of cancer-fighting techniques.
Is it possible for this person’s future children to inherit this
cancer-causing mutation? Be specific when you explain why or
why not.
4. Why do cells which lack cell cycle control exhibit karyotypes
which look physically different than cells with normal cell
cycle.

11. 5. What are HeLa cells? Why are HeLa cells appropriate for this
experiment?
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