Problem set 2, Spring 2016
8 points total
student name:
1. Diagram anaphase of mitosis for a diploid organism that contains 2 pairs chromosomes – 1
long and 1 short.
2. Diagram metaphase of mitosis for a haploid organism that contains 2 chromosomes.
Note that haploid
cells can undergo
mitosis just fine.
3. Mitosis resembles the second meiotic division. How are they similar? How do they differ?
Similar:
-same basic steps
-overall process similar
-spindle attaches to both
sides of centromere
Differ:
-ploidy of starting cell
reduced in meiosis II
-2nd meiotic division
produces 4 cells
-mitosis gives genetically
identical daughters
-meiosis produces gametes
1
Problem set 2, Spring 2016
8 points total
student name:
4. In studying a eukaryotic organism A. farlowae, recently discovered on an asteroid floating in
space, you find that it has a rather unusual meiosis. In A. farlowae, cells destined to undergo
meiosis skip S-phase, and then undergo only the first meiotic division. Draw out prophase,
metaphase, and anaphase of meiosis, and the daughter cells produced by meiosis, in A.
farlowae showing the chromosomes. Assume A. farlowae is diploid with three pairs of
homologous chromosomes. What are the consequences of this unusual type of meiosis?
prophase I
metaphase
I
anaphase I
telophase I
Only two cells will result rather than the usual four. In addition, the lack of sister
chromatids may cause problems for crossing over.
2
Problem set 2, Spring 2016
8 points total
student name:
5.
A
B
C
c
B
B
A
A
a
B
A. This diploid cell goes through a
normal mitotic cell cycle. Show
metaphase of mitosis and the
daughters produced, including
genes and chromosomes.
Note: Daughters are identical to
starting cell. Just draw two of them.
C
C
a
a
c
c
B
B
B. Show chromosomes and spindle of this cell in anaphase II of meiosis. (You don’t need to
include the genes.)
3
Problem set 2, Spring 2016
8 points total
student name:
6. E. qinae is a newly discovered red-spotted poison dart frog from Costa Rica. Chromosome
analysis of E. qinae indicates that the species is diploid with two pairs of chromosomes, one
long and one short. Simple genetic analysis indicates that the gene (R) that specifies the red
spots is located on the long chromosome, and a gene (L) that specifies body length resides on
the short chromosome.
A. Show the products at the beginning of G1 phase of a single mitosis of a E. qinae cell.
Assume the parent cell is heterozygous (i.e. R on one homolog and r on the second, L on
one homolog and l on the second) for both genes. How many chromosomes are present
in each cell? How many chromatids are present in each cell?
R l
R l
L
r
r
L
4 chromosomes, 4
chromatids
B. Diagram the appearance of the chromosomes at metaphase of meiosis I. Draw a circle
around the homologous chromosomes and a box around the sister chromatids. Assume
the parent cell is heterozygous for both genes.
R
r
L
l
4
Problem set 2, Spring 2016
8 points total
student name:
7. Do the following occur in meiosis I, meiosis II or mitosis? (Each blank may contain more
than one answer.
meiosis I
a. At least one crossover per homologous pair can occur
b. chromosomes line up singly along the metaphase plate
mitosis,meiosis II
meiosis I
c. ploidy level is decreased by half
d. DNA synthesis takes place prior to division
mitosis,meiosis I
e. Produces somatic cells
mitosis
f. Homologous chromosomes separate from each other
meiosis I
8. The cells shown in A through D all came from the same individual. In the spaces below each
cell, identify the type of division (mitosis or meiosis) taking place and the stage of that division
represented in the cell (anaphase, prophase I, etc.).
a.
b.
Division: meiosis I
Stage:
anaphase I
Division: mitosis
Stage:
anaphase
c.
d.
5
Problem set 2, Spring 2016
8 points total
student name:
Division: meiosis I
metaphase I
Stage:
Division:meiosis II
Stage: anaphase II
The following questions refer to the figures shown above in a – d.
How many chromosomes in cell in d?
6
In which cell(s) are homologues separating?
How many chromatids?
a
In which cell(s) are sister chromatids separating from each other?
6
b, c
12