"!$#&%'
1. On a separate page, draw each of the five mitotic stages (interphase, prophase, metaphase,
anaphase and telophase) as you observed them in the whitefish blastula cells and in the onion root
tip cells. Indicate the magnification you used and label the features that you observed.
• High-power magnification is 450× for most microscopes; could be 420× or 430× for some.
• In the onion, should label cell wall, chromosomes, nucleus (in interphase)
• In the whitefish, should label cell membrane, chromosomes, nucleus (in interphase), spindle fibers
• Here is an example of a reasonable drawing for the onion cells:
Interphase
Prophase
Metaphase
Anaphase
Telophase
2. What differences did you observe between the dividing plant and animal cells?
•
In the animal cells, the spindle fibers are very visible, and there is no cell wall. The two
daughter cells are the same size as the parent cells, because the cells grow as they are
dividing.
• The plant cells have a cell wall, the spindle is not visible, and the daughter cells are half
the size of the parents because they divide first and then make more cell wall later.
3. Record the number of onion root cells in each phase of the mitotic cell cycle in the first row of
this table. Combine your counts with your partners’ to get a larger sample size. Then calculate
the percentage of cells in each stage. Use this information to draw a pie chart in Excel that
represents the process of meiosis and has a “slice” for each stage.
Data will vary from group to group. However, interphase should have the greatest percentage of
cells. Prophase should be next but might not appear that way in some slides. Metaphase and
anaphase are very short.
Here is some sample data:
Interphase
number
of cells
percentage
of cells
Prophase
(*)
+,)
(.)*/
+,)*/
Metaphase
-
-*/
Anaphase
(
(*/
Telophase
+*+
+*+,/
11
6
Interphase
3
Prophase
Metaphase
15
Anaphase
65
Telophase
4. Which phase of the cell cycle is the longest, according to your data? Why do you think this is
true?
Interphase is the longest, because it takes time for cells to prepare for division, replicate DNA, etc.
5. Considering only the four phases in the actual cell division (prophase, metaphase, anaphase,
telophase), which is the longest? Why do you think this is true?
Prophase is the longest of the mitotic phases, because there is a lot that must be accomplished before
the actual division of the chromosomes can begin: breakdown of nuclear membrane, condensation of
chromosomes, synthesis of spindle, etc. (But if your data didn’t show prophase to be the longest, you
got credit for a good explanation that matched up with your data.)
6. In the mitosis simulation where you started with four chromosomes, what were the chromosome
numbers for your imaginary cell?
Beginning
N=____2____
2N=_____4_____
After Replication
N=____2____
2N=_____4_____
End:
N=____2____
2N=_____4_____
7. At the beginning of mitosis, were the cells haploid or diploid? At the end?
Diploid at the beginning and at the end.
8. At the end of the mitosis simulation, were the daughter cells genetically identical to each
other, or were they different? Explain briefly.
Genetically identical, because an exact copy of each chromosome is made (sister chromatid),
and then the two copies are divided up.
9. Fill in the chart below for the meiosis simulation:
Stage
Number of Chromosomes
Haploid or Diploid?
Beginning of Meiosis I
4
Diploid
End of Meiosis I
2
Haploid
End of Meiosis II
2
Haploid
10.
At the end of meiosis II, how many cells did you have? How are they different from the
cells at the end of meiosis I?
There are four cells at the end of meiosis II. At the end of meiosis I, each chromosome still
had two sister chromatids joined together. During meiosis II, the sisters separated, so the
four cells at the end have only one copy of each chromosome (as well as only one from each
homologous pair).
"!$#&%'
1. On a separate page, draw each of the five mitotic stages (interphase, prophase, metaphase,
anaphase and telophase) as you observed them in the whitefish blastula cells and in the onion root
tip cells. Indicate the magnification you used and label the features that you observed.
• High-power magnification is 450× for most microscopes; could be 420× or 430× for some.
• In the onion, should label cell wall, chromosomes, nucleus (in interphase)
• In the whitefish, should label cell membrane, chromosomes, nucleus (in interphase), spindle fibers
• Here is an example of a reasonable drawing for the onion cells:
Interphase
Prophase
Metaphase
Anaphase
Telophase
2. What differences did you observe between the dividing plant and animal cells?
•
In the animal cells, the spindle fibers are very visible, and there is no cell wall. The two
daughter cells are the same size as the parent cells, because the cells grow as they are
dividing.
• The plant cells have a cell wall, the spindle is not visible, and the daughter cells are half
the size of the parents because they divide first and then make more cell wall later.
3. Record the number of onion root cells in each phase of the mitotic cell cycle in the first row of
this table. Combine your counts with your partners’ to get a larger sample size. Then calculate
the percentage of cells in each stage. Use this information to draw a pie chart in Excel that
represents the process of meiosis and has a “slice” for each stage.
Data will vary from group to group. However, interphase should have the greatest percentage of
cells. Prophase should be next but might not appear that way in some slides. Metaphase and
anaphase are very short.
Here is some sample data:
Interphase
number
of cells
percentage
of cells
Prophase
(*)
+,)
(.)*/
+,)*/
Metaphase
-
-*/
Anaphase
(
(*/
Telophase
+*+
+*+,/
11
6
Interphase
3
Prophase
Metaphase
15
Anaphase
65
Telophase
4. Which phase of the cell cycle is the longest, according to your data? Why do you think this is
true?
Interphase is the longest, because it takes time for cells to prepare for division, replicate DNA, etc.
5. Considering only the four phases in the actual cell division (prophase, metaphase, anaphase,
telophase), which is the longest? Why do you think this is true?
Prophase is the longest of the mitotic phases, because there is a lot that must be accomplished before
the actual division of the chromosomes can begin: breakdown of nuclear membrane, condensation of
chromosomes, synthesis of spindle, etc. (But if your data didn’t show prophase to be the longest, you
got credit for a good explanation that matched up with your data.)
6. In the mitosis simulation where you started with four chromosomes, what were the chromosome
numbers for your imaginary cell?
Beginning
N=____2____
2N=_____4_____
After Replication
N=____2____
2N=_____4_____
End:
N=____2____
2N=_____4_____
7. At the beginning of mitosis, were the cells haploid or diploid? At the end?
Diploid at the beginning and at the end.
8. At the end of the mitosis simulation, were the daughter cells genetically identical to each
other, or were they different? Explain briefly.
Genetically identical, because an exact copy of each chromosome is made (sister chromatid),
and then the two copies are divided up.
9. Fill in the chart below for the meiosis simulation:
Stage
Number of Chromosomes
Haploid or Diploid?
Beginning of Meiosis I
4
Diploid
End of Meiosis I
2
Haploid
End of Meiosis II
2
Haploid
10.
At the end of meiosis II, how many cells did you have? How are they different from the
cells at the end of meiosis I?
There are four cells at the end of meiosis II. At the end of meiosis I, each chromosome still
had two sister chromatids joined together. During meiosis II, the sisters separated, so the
four cells at the end have only one copy of each chromosome (as well as only one from each
homologous pair).