Exam 3
1. Discuss the importance of the cell cycle check points. Where are they? What do they do?
Answer in complete sentences.
To prevent a compromised cell from dividing, there are cell cycle checkpoints to check for abnormalities.
2. How do the number of chromosomes in the daughter cells at the end of mitosis
and cytokinesis compare with their parent cell when it was in G 1 of the cell cycle? Use complete
sentences for your answer.
The daughter cells have the same number of chromosomes and the same amount of DNA.
3. Identify one difference between binary fission and mitosis and discuss why is it significant.
Binary Fission happens to bacteria and prokaryotes, it occurs in non-membrane bound organelles.
Mitosis occurs in eukaryotes and it is the process of multiplying (splitting into two) membrane bound
organelle cells.
4. Why might there be a difference between the rates of cell division found in different types such
as skin versus neurons? Answer in complete sentences.
5. Why is sexual reproduction so common, in an evolutionary sense, given the disadvantages in
expending energy to find/attract a mate? Explain using complete sentences.
The variation that sexual reproduction creates among offspring is very important to the survival and
reproduction of those offspring.
6. Discuss the inversion of chromosome 18 and evolution of humans. Answer in complete
sentences.
The inversion of chromosome 18 appears to have contributed to the evolution of humans. This
chromosomal inversion is not present in our closest genetic relative, the chimpanzee.
7. Trisomy 21, or Down syndrome, results from non-disjunction. Describe the data from the figure
below. Be sure to include percentage risk as well as age in your description. Use this data to
support your opinion as to what age women should really be concerned about the increased rick
of offspring developing Down syndrome.