Download Investigation 7: Cell Division: Mitosis and Meiosis

2014
Investigation 7: Cell Division: Mitosis and Meiosis
(Please follow the format and order listed below, this lab my be sent
electronically or in paper.
I. Background Information ( please use at least 2 references in this section,
one can be your lab manual and the other can be your textbook, but include the
page number)
1. Describe the events in the cell cycle and how these events are controlled.
2. Explain how DNA is transmitted to the next generation via mitosis.
3. Explain how DNA is transmitted to the next generation via meiosis followed
by fertilization.
4. Explain how meiosis and crossing over-leads to increased genetic diversity,
which is necessary for evolution.
Part I- Modeling Mitosis- Model and label mitosis and meiosis, take a photo of
each phase. Answer the following questions:
1. If a cell contains a set of duplicated chromosomes, does it contain any more
genetic information than the cell before the chromosomes were duplicated?
Explain.
2. What is the significance of the fact that chromosomes condense before they
are moved?
3. How are the chromosome copies, called sister chromatids, separated from
each other?
4. What would happen if the sister chromatids failed to separate?
Part II- Modified- Counting cells in Interphase and in mitosis- see table 1- page
88
Onion Root tip cell phase data
Tip
1
2
3
Your total
Class Total
Number of cells
Interphase
Mitosis
Total
Part III- Loss of Cell Cycle Control in Cancer
Using the powerpoint presentation, your lab manual and an internet search to ,
relating to Case 1 HeLa cells and answer the following questions:
1. What are cyclins and cyclin dependent kinases? What do these proteins do in
a cell?
2. How are normal cells and cancer cells different from each other?
3. What are the main causes of cancer?
4. What goes wrong during the cell cycle in cancer cells?
5. What makes some genes responsible for an increased risk of certain cancers?
6. Do you think that the chromosomes might be different between normal and
cancer cells?
7. How does infection with human papillomavirus virus (HPV) increase the risk of
cervical cancer?
Case 2 : Philadelphia Chromosomes
Use the internet, your lab manual and your textbook to research the following
questions:
1. What happens in a normal cell if the DNA has mutations?
2. What would happen if cells with mutated DNA replicated?
3. How do cells monitor DNA integrity?
4. How are the chromosomes different in the cancer cells compared to normal
cells?
5. How could these differences lead to cancer?
Part V- Meiosis and Crossing Over in Sordaria
Procedure: Describe what you did from the beginning (inoculation to counting
the Asci)
Data: Include pictures of your final product.
Analyze the class data table.
Page 95 lab manual
Table 3. Analysis of Results - Total Class results
Number of
Asci
Showing 4:4
Pattern
Cindy 17
Ashley 20
Wajiha 19
Laura 33
Kassie 37
Josh and
Chris 18
Lotta
Shreyas
Christina
Number of
Asci showing
crossing
over
11
11
12
0
11
11
Total # of
Asci
28
31
31
33
48
29
% Asci
Showing
Crossover
Divided by 2
Gene to
Centromere
Distance
(map units)
Questions:
1. Why did you divide the percentage of asci showing crossover (recombinant )
by 2?
2. The published map distance between the spore color gene and the
centromere is 26 map units. How did the class data compare with this distance?
3. How can you account for any disparities between the class data and the
published data?
4. Illustrate in words or diagrams what happened during meiosis to produce the
results you found.
5. Do you think the Philadelphia chromosome is a result of crossing over as
seen in this part of the investigation or some other chromosomal abnormality?
Explain your answer.
Conclusion: Due to all of the questions in the lab your will not be required to
write an additional conclusion.