Bio Chap 12
Which of the following molecules is a protein maintained at steady levels throughout the cell cycle that requires cyclin to become catalytically active?
Cdk
In a diploid cell with 5 chromosome pairs (2n = 10), how many centromeres will be found in a nucleus at G2 of the cell division cycle?
10
In a diploid cell with 5 chromosome pairs (2n = 10), how many sister chromatids will be found in a nucleus at prophase of mitosis?
20
Which of the following properties is associated with a cyclin-dependent kinase (Cdk)?
A Cdk is an enzyme that attaches phosphate groups to other proteins.
Certain unicellular eukaryotes, including diatoms and some yeasts, have mechanisms of nuclear division that may resemble intermediate steps in the evolution of mitosis. Which of the following is a characteristic feature of nuclear division in these organisms?
Chromosomes are segregated by a mitotic spindle, but the nuclear envelope remains intact during division.
In the figure, which number represents DNA synthesis?
II
In the figure, G1 is represented by which numbered part(s) of the cycle?
I and V
In the figure, at which of the numbered regions would you expect to find cells at metaphase?
III only
Which of the following molecules triggers the cell's passage past the G2 checkpoint into mitosis?
MPF
Which of the following molecules is released by platelets in the vicinity of an injury?
PDGF
How is plant cell cytokinesis different from animal cell cytokinesis?
Plant cells deposit vesicles containing cell-wall building blocks on the metaphase plate; animal cells form a cleavage furrow.
Certain cell types normally have several nuclei per cell. How could such multinucleated cells be explained?
The cell underwent repeated mitosis, but cytokinesis did not occur.
Early observations of a cultured cell line indicated that the cells did not exhibit either density-dependent inhibition or anchorage dependence. What do these observations suggest about this cell line?
The cells show characteristics of tumors.
In what way do kinetochore microtubules facilitate the process of splitting the centromeres?
They create tension by pulling toward opposite poles.
Why do neurons and some other specialized cells divide infrequently?
They have entered into G0.
Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely
a plant cell in the process of cytokinesis
Metaphase is characterized by
aligning of chromosomes on the equator
What is the name of the microtubule-organizing center found in animal cells as an identifiable structure present during all phases of the cell cycle?
centrosome
One difference between cancer cells and normal cells is that cancer cells
continue to divide even when they are tightly packed together.
Which of the following molecules is a protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex?
cyclin
What two components constitute an active MPF?
cyclin and a cyclin-dependent kinase
Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to
disruption of mitotic spindle formation.
The beginning of anaphase is indicated by which of the following processes?
enzymatic cleavage of cohesin
Besides the ability of some cancer cells to over proliferate, which of the following situations might logically result in a tumor?
lack of appropriate cell death
The M phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does not happen, cells would most likely be arrested in
metaphase
Which of the following does not occur during mitosis?
replication of DNA
Which of the following events occurs during interphase of the cell cycle?
replication of DNA
The mitotic spindle plays a critical role in which of the following processes?
separation of sister chromatids
FtsZ is a bacterial cytoskeletal protein that forms a contractile ring involved in binary fission. Its function is analogous to
the cleavage furrow of eukaryotic animal cells
The decline of MPF activity at the end of mitosis is due to
the degradation of cyclin.
