2.	What is the function of mitosis in a cell that is about to divide?

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Table 1: Number of cells observed in each stage of the cell cycle (2 pts)
Number of cells in
Total number
Stage
Predicted %
stage
of cells counted*
Interphase

65

Prophase

65

Metaphase

65

Anaphase

65

Telophase

65

Totals

Calculated %

65
NOTE: You do not have to draw the cells in each of the stages.

Questions (6 pts)
1. What stage of the cell cycle (not just mitosis) were most of the onion root tip cells in?
Does this make sense? Why? Cite source(s) used.

2. What is the function of mitosis in a cell that is about to divide? Cite source(s) used.

3. How accurate were your time predictions, based on your data, for each stage of the cell
cycle?

Lab 12 Experiment 1: Meiosis
Read through the Lab 12 Introduction material and the instructions for the Lab 12 Experiment
1. Pay attention to the added information under the Week 4 Experiment link regarding these
experiments! In the table below, describe the major events that take place in each stage of
Meiosis and indicate the number of chromosomes in each. Cite your sources! (14 pts)

Phase

Major Events

# of
Chromosome
s in each cell

Meiosis I
Prophase I

Nuclear membrane breaks down and chromosomes
condense. Two sets of homologous chromosomes
are attached at the centromere. Crossing over will
occur between the homologous pairs.

4

Metaphase I
Anaphase I
Telophase I
Meiosis II
Prophase II
Metaphase II
Anaphase II
Telophase II
Sources used:

Questions (12 pts)
1. Name at least two differences between Meiosis I and Meiosis II in terms of what is
produced and what occurs with the chromosomes. Cite source(s) used.
2. Name and briefly describe two processes that occur during meiosis that contribute to
genetic variation. Cite source(s) used.
3. At the beginning of meiosis I are the cells diploid or haploid?

What are they at the beginning of meiosis II?
4. Why is it necessary to reduce the chromosome number of gametes (egg and sperm), but
not other cells of an organism? Cite source(s) used.
5. If humans have 46 chromosomes in each of their body cells, determine how many
chromosomes you would expect to find in the following cells:
Sperm _______________
Egg _________________
Daughter cell from mitosis __________
Daughter cell from Meiosis II __________
6. Investigate one of the diseases from the following list. Include the following:
• Name of the disease or disorder
• What is the type of mutation and when might it occur?
• What chromosome is affected?
• What are the consequences?
• What is the incidence rate of this disease or disorder?
Down Syndrome
Jacobs Syndrome
Patau Syndrome
Cystic fibrosis

Turner Syndrome
Triple X
Hemophilia
Prader-Willis Syndrome

Klinefelter Syndrome
Edward Syndrome
Cri-du-chat Syndrome
Fragile X

Remember to properly cite your sources! (Minimum of 250 words) (6 pt)