Download Cell division and Cell Cycle problem set Define Haploid: Diploid

Cell division and Cell Cycle problem set
1. Define
a. Haploid:
b. Diploid:
c. Crossing over:
d. Chaismata:
e. Gametes:
f. Cytokinesis:
g. Interphase:
h. Homologous Chromosome:
i. Chromatids:
j. Synapse:
2. Fill in empty cells in the table based on your understanding of concepts in cell division:
Observation
Stage of Cell
Mitosis/Meiosis
division
No. of
chromosomes
Cell type
2n
Germ cells
Crossing over
Prophase
Chromosomes align
in the equatorial
plane
Somatic cells
Anaphase
Chromosomes align
in the equatorial
plane
Somatic cells
n
3. If 15 cells in the body were to undergo repeated mitosis, how many cells would they yield
after 8 rounds of mitotic division?
4. The cell cycle of an average mammalian cell is illustrated below.
G
G1 start: t1= 0 hours
G1/S : t2= 9.5 hours
S/G2 : t3= 18.5 hours
G2/M : t4= 23.5 hours
M/G1 : t5= 24 hours
a. How long did it take for the above-illustrated mammalian cell to complete one cell cycle?
b. How long did the mitosis/cytokinesis phase (M phase) last? What % of the total cellcycle time does that constitute to?
c. What phase takes the longest time to complete during cell cycle and what % of the total
cell-cycle time does that constitute to? Explain why you think this might be the longest
phase of the cell cycle.
d. How long was the S phase? What is happening in the cell during the S phase?
5. The approximate cell cycle duration of fast-dividing PC3 cells (mammalian cells derived
from bone metastasis of prostate cancer cells) is 24 hours. PC3 cells are widely used to study
prostate cancer. These cells are routinely grown in research labs in 10 cm (diameter) circular
dishes as a monolayer (single layer of cells) to study the various aspects of prostate cancer.
When healthy, these cells appear spherical under a microscope with an average diameter of
10m.
a. If 30% of the surface area of the dish is covered by the cells at t=0 hours, approximately
how many cells are there on the plate?
b. What percent of the surface area of the plate would be covered by PC3 cells at t=72
hours? Ignore cell death to solve this problem.
c. How long would it take starting from time t=0 hours, for the cells to cover 100 percent
area of the 10cm circular dish? Ignore cell death to solve this problem.
d. At time t=40 hours, these cells are treated with a drug that is being tested for prostate
cancer treatment. This drug acts at the G2/M checkpoint in the cell cycle and slows down
mitotic entry in these cells and thereby increasing the cell cycle duration from 24 hours to
32 hours. If these cells are counted 40 hours post drug treatment how many cells would
you estimate to be present in the 10cm dish?
e. These mammalian cells can be detached and removed from the dish using the enzyme
trypsin. The detached cells can be then re-plated (added) to a fresh 10cm dish at desired
cell density. This fact is routinely employed in research labs to expand the number of
cells and to make them available for different experiments. If it is desired that 90% of the
dish be covered by PC3 cells 24hours post re-plating, how many PC3 cells should be
plated in the 10cm dish at time t=0 hours?