Review of Unit 4: Cell Cycle
Name ______________________ Date ___________
Chi-square
Case 1: Null hypothesis: Lectin will not cause an increase in mitosis in onion root meristems.
Interphase
Mitosis
total cells
observed
(lectin)
28
22
50
expected
(no lectin)
35
15
50
o-e
(o-e)^2
-7
49
7
49
Chi-square= Sum[(o-e)^2]/e
[(o-e)^2]/e
1.40
3.27
4.67
degrees of freedom = number of groups (2 interphase and mitosis) minus 1 = 1
Results: The chi-square value is 4.67 (P<0.05) which indicates that there is a significant difference between
the two groups. There were more mitotic figures in the group with lectin that without. The null hypothesis
is rejected.
Conclusion: Lectin increases mitosis in onion root meristems.
Case 2: Null hypothesis: Lectin will not cause an increase in mitosis in corn root meristems.
Data:
with lectin: 28 interphase, 22 mitosis
without lectin: 33 interphase, 17 mitosis
Interphase
Mitosis
total cells
observed
expected
50
50
Results: The chi-square value is ________ (P
Conclusion:
o-e
(o-e)^2
Chi-square= Sum[(o-e)^2]/e
0.05) which indicates that
[(o-e)^2]/e
Case 3: Lectin was tested on radish roots.
Null hypothesis: ___________________________________________________________________
_________________________________________________________________________________
Data: with lectin: 25 interphase, 25 mitosis
without lectin: 34 interphase, 16 mitosis
Results:
Conclusions:
Things to consider:
1. What are the advantages of sexual reproduction to a population?
2. Discuss three ways sexual reproduction leads to genetic variation.
3. How is the cell cycle controlled?
4. What happens if the cell cycle is not well controlled? Include apoptosis and p53 as part of your
discussion.
5. What would happen to mitosis if a cell’s tubulin is not functional?
6. What are the differences between mitosis and meiosis?