Meiosis and Mitosis Lab
Overview:
Unique
Diploid (2x)
2
Identical
4
Mitosis is the division of a ____diploid_________ cell to produce _2___ new
_____identical_____ cells. Meiosis is also the division of a ____diploid____cell. However, it
produces __4____ new, _____Unique______cells.
Cell cycle:
1. Define the term cell cycle?
The cell cycle is the process of cells
2. What is the meaning of genome? Compare your genome to that of a prokaryotic cell.
3. Give 3 reasons why a mitotic cell division is important?
a)
b)
c)
4. Give a brief explanation of what happens in each part of the cell cycle as indicated.
G1
Interphase
S
Mitosis
G2
Cytokinesis
5. List the steps and images of Mitosis in the correct order and mention a major event that
occurs in each stage.
6. Why is it important for multi-cellular organisms to regulate Mitosis? Why would it be
bad for cells to divide at any time?
7. How does cytokinesis differ in plants and animals?
 The following table represents the number & percent of cells counted for each phase
of mitosis.
8. Calculate the percentage of cells in each phase of mitosis.
Phase
Number of
Cells
Interphase
46
Prophase
23
Metaphase
15
Anaphase
12
Telophase
14
Percent Cells
9. In which phase do cells spend the most time? Use the data above to support your
answer.
Cytokinesis
10
10. Why do cells spend a significant portion of Mitosis in prophase?
11. List the 6 steps of cell division in order and briefly describe the events of each.
Technically, which step marks the end of mitosis?
12. How many chromosomes are present in a human cell at the beginning of prophase?
______
Chromatids? ______
13. What role do cyclin and CDK play in regulating cell division?
14. What happens to cyclin levels as the cell passes through the S phase, the G2 phase and
enters mitosis?
15. What happens to cyclin levels between mid-mitosis and the G1 phase?
16. List the 3 checkpoints cells must pass through in order to carry out the phases of the cell
cycle. For each checkpoint, list the tasks and/or control mechanisms that allow the cell
to proceed to the next step in the cell cycle.
I.
II.
III.
Meiosis
No
Mitosis
Duplication
+/tn
Spore cells of a certain mold known as Sordaria can be viewed under a microscope. Like most
fungi, Sordaria spends the majority of its life in the haploid stage. Some Sordaria produce black
spores (+) and some produce tan spores (tn) which are packaged in a pod-like structure called
an ascus. If one parent is homozygous black (++) and is crossed with a homozygous tan parent
(tn/tn), the hybrid will have the genotype ______ as one parent would donate the + allele and
the other would donate the tn allele. During Meiosis I, these chromosomes first undergo
________________ in which two sister chromatids are formed. During Meiosis II, the sister
chromatids split and end up in separate cells. The next phase in the formation of spores is that
each haploid cell undergoes ______________ to produce two identical haploid cells (2 black or
2 tan). When 4 black spores or 4 brown spores appear in a row, it is assumed that ________
crossing over occurred during Meiosis I.
**According to this
diagram, no crossing
over occurred during
Meiosis I between the tan
(tn) and black (+) genes.
1. Why would the chromosomes carrying the black allele (+) and the tan allele (tn) be
considered homologous chromosomes?
2. Assume that a cell has the following 4 alleles: AaBb located on 4 separate
chromosomes. Using these four alleles, sketch the following phases of meiosis. Place
each letter on a separate chromosome. The first has been completed for you.
Prophase I
Anaphase I
Cytokinesis I
Homologous
chromosomes
pair up and
may cross
over…no
crossing over
is shown here
Anaphase II
Cytokinesis II
v
3. List four differences between meiosis and mitosis.
Mitosis
Meiosis