Download Cell Cycle and Mitosis Investigation KEY

Biology
HS/Science
Unit: 06 Lesson: 02
Cell Cycle and Mitosis Lab KEY
Analysis:
1. In what stage were the majority of cells? Why do you think this is the case?
Interphase – (Answers as to why may vary but should be similar to this.): Cell division is a metabolically
expensive process and highly regulated. The cell spends most of its life in Interphase growing and getting
nutrients for the energy for cell division.
2. What percent of the cells were in the different stages?
Answers will vary based on the cell counts, so use the following as a guideline only.
Interphase: 70–80% of time
Prophase: 10–15% of time
Metaphase: 5–10% of time
Anaphase: 1–5% of time
Telophase: 1–5% of time
3. Describe the cell in each of the different stages.
a.
Interphase: In interphase, the cell looks like it “normally” does – the nucleus is a large,
centralized structure in the middle of the cell and none of the nuclear contents are visible.
b.
Prophase: In prophase, the chromosomes are visible and you cannot see a nuclear membrane.
c.
Metaphase: In metaphase, the chromosomes line up in the middle of the cell.
d.
Anaphase: In anaphase, duplicated chromosomes move apart from each other.
e.
Telophase: In telophase, the cell begins to resemble Interphase, except that there are two nuclear
areas in the cell.
4. Why is it important that the genetic material be duplicated before the cell divides?
If the DNA does not duplicated, then the daughter cells end up with only half of the DNA. This means an
incomplete set of genes.
5. Why is it important that this process be highly regulated? Discuss what might happen if cells were allowed to
divide in an uncontrolled fashion.
Because cells divide only for growth and to repair damaged tissue, most of the cell cycle does not need to
be spent in mitosis. If mitosis is not regulated, then cells can divide out of control forming masses known
as tumors (cancer).
6. Do you think cell division occurs at the same rate in skin cells as it does in blood cells? Explain your answer.
Cell division occurs at a higher rate in cells that are damaged more often. Since skin is constantly being
shed, as it interacts with the environment, these cells would divide more often than blood cells.
©2012, TESCCC
05/07/13