Name_________________________________
ALE #4 Mitosis & Meiosis
Control of Cell Division and Cancer
22. Define the functions for each of the following.
a.) Proto-oncogenes
b.) Oncogenes
c.) Tumor suppresser genes
d.) p53 gene
23. Why doesn’t one mutant Tumor Suppresser Gene (e.g. one mutant p53 gene) cause
cancer?
24. a.) What kind of gene is the BRCA 1 gene?
b.) Why do women that inherit a mutant BRCA 1 gene have a very high chance (8090% chance) of getting breast cancer?
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c.) Why are the percentages much lower for the average woman?
25. List three different factors that can cause genes (e.g. p53 gene, BRCA 1 gene, etc.) to
mutate
a.)
b.)
c.)
26. Phase-specific Chemotherapies. Indicate how each of the following methods of
controlling the growth of cancerous cells can be accomplished.
a.) How could you prevent the cells from entering mitosis?
b.) Once started, how can you stop the chromosomes from completing mitosis?
c.) How could you block the S phase?
27. What is cancer?
28. How are cancerous cells different from normal cells?
29. How do you get cancer? i.e. What genes need to mutate for normal cells to become
cancerous cells?
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Meiosis
1. a. What is the function of meiosis?
b. What kinds of cells are produced by
meiosis?_____________________________________________
c. Are these cells haploid or diploid?
______________________________________________________
d. What would be the genetic consequences to a species (i.e. to the number of
chromosomes) if mitosis, rather than meiosis, produced these cells?
2. Overview of Meiosis…
a. How do the chromosomes align at metaphase I of meiosis?
b. What separates during anaphase I of meiosis?
c. How do the chromosomes align at metaphase II of meiosis?
d. What separates during anaphase II of meiosis?
e. How do the daughter cells compare genetically?
f. Are the daughter cells haploid or diploid?
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Meiosis—Apply your knowledge!
30. The following questions refer to the sketch below that represents the nucleus of a skin
cell from a hypothetical species of worm.
a.) In figure 1, above, use a pencil or pen to shade in the maternal chromosomes. Leave
the paternal chromosomes as they are (white).
b.) Draw the chromosomes of a cell from the species of worm in figure 1 in each of the
following stages of cell division—mitosis or meiosis. Be sure you have the correct
number of chromosomes in each of your diagrams. Use the maternal/paternal colors
you used in part a, above.
(i.) Skin cell in metaphase of mitosis
(ii.) Skin cell in anaphase of mitosis
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(iii.)
Pregamete cell in metaphase I of meiosis
(iv.)
Pregamete cell in anaphase I of meiosis
(v.)
The two cells at end of meiosis I. Are
these cells haploid or diploid? ______________ How can you tell?
(vi.)
The four cells at the end of meiosis II. Are
these cells haploid or diploid? ______________ How can you tell?
31. a. Explain why the age of the mother and not that of the father is correlated with the
probability of having a child with Down syndrome.
b. Explain how nondisjunction of chromosomes during anaphase I of meiosis can
lead to Down syndrome.
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c. Starting with a cell with four chromosomes (i.e. 2n = 4) in metaphase I of meiosis,
show how an error in anaphase I can lead to a situation that could lead to Down
syndrome
Nondisjunction at Anaphase I
n+1
n+1
n-1
Metaphase I
Anaphase I
n-1
Metaphase II
Anaphase II
Gametes
32. Explain how each of the following leads to genetic variation during meiosis.
a. Independent assortment of chromosomes during metaphase I of meiosis
b.
Cross over during prophase I of meiosis
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7. Compare mitosis and meiosis by completing the table below.
Mitosis
Type of cells involved
Number of cell divisions involved
Number of daughter cells
How do the daughter cells compare
genetically?
Are the daughter cells diploid (2n) or
haploid (n)?
Involves homologue pairing and cross
over?
Role played in organism
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Meiosis