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If a cell at metaphase of mitosis contains 32 sister chromatids, how many chromosomes will be present in a G1 cell?
16
A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 10 picograms of DNA per nucleus. Approximately how many picograms of DNA would be found in a nucleus at prophase of mitosis?
20
Beginning with a fertilized egg (zygote), how many cells will be present in the embryo following five rounds of cell division
32
In a diploid cell with four chromosome pairs (2n = 8), how many centromeres will be found in a nucleus at G2 of the cell division cycle?
8
A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain? See Concept 12.1 (Page)
92
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.
Which of the following structures or molecules is required in order for motor proteins to facilitate movement of chromosomes toward the poles in mitosis?
ATP as an energy source
Which of the following statements best describes density-dependent inhibition?
As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells, and they signal each other to stop dividing.
How do cancer cells differ from normal cells?
Cancer cells may be immortal.
Eukaryotic chromatin is composed of which of the following macromolecules?
DNA and proteins
The continuity of life is based on heritable information in the form of DNADNA. How does the process of mitosis faithfully parcel out exact copies of this heritable information in the production of genetically identical daughter cells?
During mitosis, each chromatid of a duplicated chromosome becomes attached to the microtubule of one of the mitotic spindles. At anaphase, mitotic spindles pull the chromatids toward the poles of the cell, therefore forming two identical chromosomal sets at each pole.
Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle?
G1
Which of the following correctly matches a phase of the cell cycle with its description?
G1, follows cell division
Amount of DNA per nucleus over the cell division cycle.Which region of the accompanying figure represents S phase?
II
The unlettered circle at the top of the accompanying figure shows a diploid nucleus with four unreplicated chromosomes. The circles labeled 1 to 5 show various combinations of these chromosomes.
II
A research team used a culture of lymphocytes with radioactively labeled T nucleotides to study the cell cycle. They found that the lymphocytes incorporated the labeled nucleotide at a significantly higher rate after a pathogen was introduced into the culture. Which of the following conclusions is most consistent with the results?
Infection causes lymphocytes to divide more rapidly.
Amount of DNA per nucleus over the cell division cycle.
Line 2 contains more DNA than line 1.
In which phase of mitosis do the sister chromatids become daughter chromosomes?
anaphase
Which of the following statements best describes how cytokinesis differs between plant and animal cells?
Plant cells deposit vesicles containing cell wall building blocks on the metaphase plate; animal cells form a cleavage furrow.
How is the cell division of cancer cells like these misregulated?
Such cells do not respond to signals that normally trigger apoptosis. Such cells can divide in the absence of growth factors. Such cells do not require anchorage to a surface in order to divide. Such cells are not inhibited by density.
Which of the following statements best describes cells in culture that do not exhibit either density-dependent inhibition or anchorage dependence?
The cells show characteristics of tumors.
What are the genetic or other changes that might have caused these cells to escape normal cell cycle regulation?
The underlying basis for this altered behavior is a series of genetic and cellular changes, including mutations in genes whose protein products normally regulate the cell cycle. These gene products are often proteins that function in cell signaling pathways.
Which of the following statements describing kinetochores is correct?
They are sites at which microtubules attach to chromosomes.
Which of the following statements best explains how neurons and some other specialized cells divide infrequently?
They have entered into G0.
What is true of all cancers?
They have escaped normal cell cycle controls.
Which of the following statements describes a characteristic feature of metaphase?
alignment of chromosomes on the equator of the cell
Cytochalasin B is a chemical that disrupts microfilament formation. With which aspect of cell division would cytochalasin B interfere?
cleavage
One difference between cancer cells and normal cells is that cancer cells
continue to divide even when they are tightly packed together.
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.
Which of the following occurs in binary fission but not in mitosis with cytokinesis?
duplicated chromosomes attach to the plasma membrane
Students in a biology lab isolated cells in various phases of the cell cycle. A population of cells that have 1 1/2 times the DNA of G1 phase cells was most likely isolated from which of the following parts of the cell cycle?
in the S phase
Why is it difficult to observe individual chromosomes with a light microscope during interphase?
interphase chromosomes are long, thin strands unlike the condensed chromosomes visible in mitosis
In some organisms, such as certain fungi and algae, cells undergo the cell cycle repeatedly without subsequently undergoing cytokinesis. What would result from this
large cells containing many nuclei
Which of the following events would be most likely to produce cells with several nuclei?
repeated mitosis without cytokinesis
Which of the following events occurs during interphase of the cell cycle?
replication of the DNA
Which of the following occurs during SS phase?
replication of the DNA
If the cell whose nuclear material is shown in the accompanying figure continues toward completion of mitosis, which of the following events would occur next?
segregation of daughter chromosomes
Movement of the chromosomes during anaphase would be most directly affected by a drug that prevents which of the following events?
shortening of microtubules
The decline of MPF activity at the end of mitosis is due to
the degradation of cyclin.
Why do some species employ both mitosis and meiosis, whereas other species use only mitosis?
they need both if they are reproducing sexually
