Chapter 12 Test Flashcards
The centromere is a region in which
chromatids remain attached to one another until anaphase.
What is a chromatid?
a replicate chromosome
Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells?
32
If there are 20 chromatids in a cell, how many centromeres are there?
10
For a newly evolving protist, what would be the advantage of using eukaryote -like cell division rather than binary fission?
Cell division would allow for the orderly and efficient segregation of multiple linear chromosomes.
How do the daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in G1 of the cell cycle?
The daughter cells have the same number of chromosomes and the same amount of DNA.
at prometaphase of mitosis
B
one daughter nucleus at telophase of mitosis
E
Which term describes two centrosomes arranged at opposite poles of the cell?
prometaphase
Which term describes centrioles beginning to move apart in animal cells?
prophase
Which is the longest of the mitotic stages?
metaphase
Which term describes centromeres uncoupling, sister chromatids separating, and the two new chromosomes moving to opposite poles of the cell?
anaphase
If cells in the process of dividing are subjected to colchicine, a drug that interferes with the functioning of the spindle apparatus, at which stage will mitosis be arrested?
metaphase
A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei each containing how many chromosomes?
46
If the cell whose nuclear material is shown in Figure 12.2 continues toward completion of mitosis, which of the following events would occur nex
formation of telophase nuclei
If there are 20 centromeres in a cell at anaphase, how many chromosomes are there in each daughter cell following cytokinesis?
20
If there are 20 chromatids in a cell at metaphase, how many chromosomes are there in each daughter cell following cytokinesis?
10
Of the following, the best conclusion concerning the difference between the S phases for beta and gamma is that
gamma contains more DNA than beta.
The best conclusion concerning delta is that the cells
are actually in the G0 phase.
Where do the microtubules of the spindle originate during mitosis in both plant and animal cells?
centrosome
If a cell has 8 chromosomes at metaphase of mitosis, how many chromosomes will it have during anaphase?
16
Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, the result would be a cell with
two nuclei.
Regarding mitosis and cytokinesis, one difference between higher plants and animals is that in plants
a cell plate begins to form at telophase, whereas in animals a cleavage furrow is initiated at that stage.
The formation of a cell plate is beginning across the middle of a cell and nuclei are re-forming at opposite ends of the cell. What kind of cell is this?
a plant cell undergoing cytokinesis
Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursor, tubulin. Surprisingly, this stops mitosis. Specifically, taxol must affect
the fibers of the mitotic spindle.
Which of the following are primarily responsible for cytokinesis in plant cells?
Golgi-derived vesicles
Chromosomes first become visible during which phase of mitosis?
prophase
During which phases of mitosis are chromosomes composed of two chromatids?
from G2 of interphase through metaphase
In which group of eukaryotic organisms does the nuclear envelope remain intact during mitosis?
B and C only
Movement of the chromosomes during anaphase would be most affected by a drug that
prevents shortening of microtubules.
Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. In which stage of the cell cycle was the nucleus with 6 picograms of DNA?
G2
A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. Those cells would have __________ picograms at the end of the S phase and __________ picograms at the end of G 2.
16; 16