meiosis final questions
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.
Where do the microtubules of the spindle originate during mitosis in both plant and animal cells?
Centrosome.
The centromere is a region in which
Chromatid remain attached to one another until anaphase.
If mammalian cells receive a go-ahead signal at the G1 checkpoint, they will
Complete the cycle and divide.
One difference between cancer cells and normal cells is that cancer cells
Continue to divide even when they are tightly packed together.
Proteins that are involved in the regulation of the cell cycle, and that show fluctuations in concentration during the cell cycle, are called
Cyclins.
If there are 20 chromatids in a cell, how many centromeres are there?
10.
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 G2.
16;16.
The cell cycle in a certain cell type has a duration of 16 hours. The nuclei of 660 cells showed 13 cells in anaphase. What is the approximate duration of anaphase in these cells?
19 minutes.
If there are 20 centromeres in a cell at metaphase, how many chromosomes are there in each daughter cell following cytokinesis?
20.
If there are 40 chromatids in a cell at metaphase, how many chromosomes are there in each daughter cell following cytokinesis?
20.
A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei each contain how many chromosomes?
46.
This is the shortest part of the cell cycle.
M.
What triggers the cell's passage past the G2 checkpoint into mitosis?
MPF.
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.
Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei re-forming on either side of the cell plate. This cell is most likely
A plant cell in the process of cytokinesis.
What is a chromatid?
A replicate chromosome.
What term describes centromeres uncoupling, sister chromatids separating and the two new chromosomes moving to opposite poles of the cell?
Anaphase.
Density-dependent inhibition is explained by what?
As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing.
What is a protein maintained at constant levels throughout the cell cycle that requires cyclin to become catalytically active?
CdK.
During which phases of the cell cycle are chromosomes composed of two chromatids?
From G2 of interphase through metaphase.
Cells that are in a nondividing state are in which phase?
G0.
Nerve and muscle cells are in this phase.
G0.
A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question is most likely in
G1.
Imagine looking through a microscope at a squashed onion root tip. The chromosomes of many of the cells are plainly visible. In some cells, replicated chromosomes are aligned along the center (equator) of the cell. These particular cells are in which stage of mitosis?
Metaphase.
Movement of the chromosomes during anaphase would be most affected by a drug that
Prevents shortening of microtubules.
Chromosomes first become visible during which phase of mitosis?
Prophase.
During which phases of the cell cycle are chromosomes composed of two chromatids?
Prophase.
What is the first stage of mitosis, in which centrosomes are in
Prophase.
What is the longest of the mitotic stages?
Prophase.
What term describes centrioles beginning to move apart in animal cells?
Prophase.
What is a general term of enzymes that activate or inactivate other proteins by phosphorylating them?
Protein kinase.
DNA is replicated at this time of the cell cycle.
S.
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.
Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, the result would be a cell with
Two nuclei.