Cell Cycle; Mitosis
Which statement provides the best description of the interphase portion of the cell cycle?
During interphase, a cell is metabolically active.
What is the correct chromosomal condition for one daughter nucleus following telophase of mitosis?
E
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
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
Nucleotides can be radiolabeled before they are incorporated into newly forming DNA and, therefore, can be assayed to track their incorporation. In a set of experiments, a student-faculty research team used labeled T nucleotides to study the incorporation of labeled nucleotides into a culture of lymphocytes. They found that the lymphocytes incorporated the labeled nucleotide at a significantly higher level after a pathogen was introduced into the culture. What might they conclude from this observation?
Infection causes lymphocytes to divide more rapidly.
Which of the following statements accurately describes the structure of a eukaryotic chromosome?
It is a single linear molecule of double-stranded DNA plus proteins.
In the cells of many eukaryotic species, the nuclear envelope has to disappear to permit which of the following events in the cell cycle?
attachment of microtubules to kinetochores
G1 is associated with which of the following cellular events?
normal growth and cell function
Spindle fibers attach to kinetochores during _____.
prometaphase
During which phase of mitosis do the chromatids become chromosomes?
anaphase
A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain?
92
If a cell at metaphase of mitosis contains 20 sister chromatids, how many chromosomes will be present in a G1 cell?
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. How many picograms of DNA would be found in a nucleus at prophase of mitosis?
16
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
Homo sapiens have 23 pairs of chromosomes. This implies that ________.
46 double-stranded DNA molecules are present in each somatic cell
DNA contains the template needed to copy itself, but it has no catalytic activity in cells. What catalyzes the formation of phosphodiester bonds between adjacent nucleotides in the DNA polymer being formed during DNA replication?
DNA polymerase
Which of the following is found in binary fission but not in mitosis?
Duplicated chromosomes attach to the plasma membrane.
If a eukaryotic cell is in the G1 phase of the cell cycle, which statement about the cell's chromosomes must be correct?
Each chromosome is made of a complex of DNA and associated proteins.
DNA replication is said to be semiconservative. What does this mean?
Each new double helix consists of one old and one new strand.
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
Cell A has half as much DNA as cells B, C, and D in a mitotically active tissue. Cell A is most likely in
G1
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 did the nucleus contain 6 picograms of DNA?
G2
Which of the following molecular characteristics cause histones to bind tightly to DNA?
Histones are positively charged, and DNA is negatively charged.
Which of the following statements best describes microtubules?
Microtubules are made up of subunits of tubulin, and are structures along which substances are transported in the cell
What is the best description of the structure of a chromosome in the nucleus of a non-dividing cell?
One long double-stranded DNA molecule, associated with many proteins.
Which of the following statements accurately describes the differences between DNA replication in prokaryotes and DNA replication in eukaryotes?
Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.
If a cell were unable to produce histone proteins, which of the following results would be a likely effect on the cell?
The cell's DNA could not be packed into its nucleus.
DNA is a self-replicating molecule. What accounts for this important property of DNA?
The nitrogenous bases of the double helix are paired in specific combinations: A with T and G with C.
Centromeres divide and sister chromatids become full-fledged chromosomes during _____.
anaphase
Why is it difficult to observe individual chromosomes with a light microscope during interphase?
They have uncoiled to form long, thin strands.
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
If the cell whose nuclear material is shown in the figure continues toward completion of mitosis, which of the following events would occur next?
formation of telophase nuclei
Scientists isolate cells in various phases of the cell cycle. They isolate a group of cells that have 1 1/2 times more DNA than G1 phase cells. What is the most likely part of the cell cycle from which these cells were isolated?
in the S phase of the cell cycle
During _____ the cell grows and replicates both its organelles and its chromosomes.
interphase
Nucleoli are present during _____.
interphase
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
Chromosomes become visible during _____.
prophase
Which of the following does not occur during mitosis?
replication of DNA
The mitotic spindle plays a critical role in which of the following processes?
separation of sister chromatids
Cytokinesis often, but not always, accompanies _____.
telophase
During _____ both the contents of the nucleus and the cytoplasm are divided.
the mitotic phase
Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol prevents microtubule depolymerization. Thus, Taxol stops mitosis by interfering with which of the following structures or processes?
the mitotic spindle
What is the function of DNA polymerase?
to add nucleotides to the 3' end of a growing DNA strand
During prophase a homologous pair of chromosomes consists of _____.
two chromosomes and four chromatids