Ch 12-13
Cytokinesis in plant cells: Which of the following statements are true of cytokinesis in plant cells? Select the two that apply
*Vesicles from the Golgi apparatus move along microtubules, coalesce at the plane of cell division, and form a cell plate. *The cell plate consists of the plasma membrane and cell wall that will eventually separate the two daughter cells.
Assume that you are dealing with a species in which the number of chromosomes in each somatic cell is 14. How many sister chromatids are present in the early telophase of mitosis?
0
A cell biologist carefully measured the quantity of DNA in grasshopper cells growing in cell culture. Cells examined during the G2 phase of the cell cycle contained 200 units of DNA. What would be the amount of DNA at G1 of the cell cycle in one of the grasshopper daughter cells?
100 units
What is the difference between a benign tumor and a malignant tumor?
Cells of benign tumors do not metastasize; those of malignant tumors do
At which stage of mitosis are chromosomes lined up in one plane in preparation for their separation to opposite poles of the cell?
Metaphase
Which of the following events does not occur during prophase of mitosis?
The mitotic spindle breaks down
During _____ sister chromatids separate.
anaphase II
In the cells of some organisms, mitosis occurs without cytoki-nesis. This will result in
cells with more than one nucleus.
Observations of cancer cells in culture support the hypothesis that cancer cells __________.
do not exhibit density-dependent inhibition
At the end of _____ and cytokinesis there are four haploid cells.
telophase II
A cell contains 40 chromatids at the beginning of mitosis. How many chromosomes will it contain at the completion of cytokinesis?
20
How many maternal chromosomes are present in a somatic human cell not engaged in cell division?
23
Meiosis I produces _____ cells, each of which is _____.
2; haploid
If the DNA content of a diploid cell in the G1 phase of the cell cycle is x, then the DNA content of the same cell at metaphase of meiosis I would be __________.
2x
If a cell contains 60 chromatids at the start of mitosis, how many chromosomes will be found in each daughter cell at the completion of the cell cycle?
30
A cell entering the cell cycle with 32 chromosomes will produce two daughter cells, each with __________.
32 chromosomes
What number and types of chromosomes are found in a human somatic cell?
44 autosomes and 2 sex chromosomes
Meiosis II typically produces _____ cells, each of which is _____.
4; haploid
How many chromatids does a human somatic cell contain after interphase and just prior to mitosis?
92
If a human somatic cell is just about to divide, it has __________ chromatids
92
Down syndrome is characterized by cells having three copies of chromosome 21. As a cell in an individual with Down syndrome prepares to enter mitosis, how many chromatids would be present?
94
Which of the following statements correctly describes the difference(s) between mitosis and binary fission?
Binary fission involves the replication and division of a single chromosome, whereas mitosis involves the division of multiple, replicated chromosomes.
The drug cytochalasin B blocks the function of actin. Which of the following aspects of the animal cell cycle would be most disrupted by cytochalasin B?
Cleavage furrow formation and cytokinesis
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.
During what phase in the cell cycle would you find the most DNA per cell?
G2
Which of the following processes does NOT occur in dividing bacteria?
Mitosis
Which life cycle stage is found in plants but not animals?
Multicellular haploid
You would be UNLIKELY to see which of the following human cells dividing?
Nerve cell
Which of these is NOT a carcinogen?
None of these, testosterone, fat, UV light, cigarette smoke
Which of the following does not occur during mitosis?
Replication of the DNA
Which of the following events does not occur during interphase of the cell cycle?
Separation of sister chromatids
Which of the following phases of mitosis is essentially the opposite of prometaphase in terms of the nuclear envelope?
Telophase
A cell biologist examined the DNA content of a cell from a fruit fly larva during the G1 phase and determined that it had 150 units of DNA. After measuring the DNA content of the same type of cell after the G2 phase, it was discovered that the cell had 300 units of DNA. How is this possible?
The DNA was replicated during the S phase of interphase, which occurs between the two G phases.
Which of the following structures is/are part of the mitotic spindle?
The aster, centresome, nonkinetochore microtubules, kinetochore microtubules
Which of the following hypotheses is best supported by observing cancer cells in a culture?
The cancer cells do not exhibit density-dependent inhibition.
Which of the following statements describes a cell that undergoes mitosis but not cytokinesis?
The cell contains more than one nucleus.
Which of the following events occurs during metaphase of mitosis?
The chromosomes align along the metaphase plate of the cell
Which of the following events occurs during prometaphase of mitosis?
The nuclear envelope fragments
How does the process of mitosis differ between most eukaryotes and other eukaryotes such as diatoms and dinoflagellates?
The nuclear envelope fragments in most eukaryotes but remains intact in diatoms and dinoflagellates.
Which of the following events occurs during anaphase of mitosis?
The sister chromatids are pulled apart toward opposite sides of the cell
What is a locus?
They can both occur in multicellular organisms
Following cytokinesis in an animal cell, how many centrioles does each new daughter cell possess?
Two
Which of the following events occurs during telophase of mitosis?
Two distinct daughter nuclei form in the cell.
Centromeres divide and sister chromatids become full-fledged chromosomes during _____.
anaphase
The phase of mitosis during which the chromosomes move toward separate poles of the cell is __________.
anaphase
Homologous chromosomes migrate to opposite poles during _____.
anaphase I
The function of the mitotic cell cycle is to produce daughter cells that __________.
are genetically identical to the parent cell (assuming no mutation has occurred)
The presence of a cell wall prevents the cell from dividing by constriction
bacteria: FALSE animals: FALSE plants: TRUE
Tubulin or tubulin-like molecules function in binary fission (in bacteria) or cytokinesis (in animals and plants)
bacteria: TRUE animals: FALSE plants: TRUE
Cells divide by constriction of a ring of protein
bacteria: TRUE animals: TRUE plants: FALSE
A biochemist measured the amount of DNA in cells growing in the laboratory and found that the quantity of DNA in the cells doubled __________.
between the G1 and G2 phases
The complex of DNA and protein that makes up a eukaryotic chromosome is properly called __________.
chromatin
One difference between cancer cells and normal cells is that cancer cells
continue to divide even when they are tightly packed together.
During interphase, the genetic material of a typical eukaryotic cell is __________.
dispersed in the nucleus as long strands of chromatin
Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of micro-tubules, its effectiveness must be related to
disruption of mitotic spindle formation.
Cytokinesis refers to __________.
division of cytoplasm
Tissue culture experiments with PDGF demonstrate that without this substance __________.
fibroblasts fail to divide
Chromatids are __________.
identical copies of each other if they are part of the same duplicated chromosome
During _____ the cell grows and replicates both its organelles and its chromosomes.
interphase
Nucleoli are present during _____.
interphase
You would know a dividing cell was a plant cell rather than an animal cell if you saw that __________.
it had formed a cell plate
You would know that a dividing cell was a plant cell rather than an animal cell if you saw that __________.
it had formed a cell plate
Homologous chromosomes move toward opposite poles of a dividing cell during __________.
meiosis I
During _____ chromosomes align single file along the equator of a haploid cell.
metaphase II
Which of the following represents a mismatch or incorrect description?
metaphase: the nuclear envelope disappears
The spread of cancer cells to other locations in the body is known as __________.
metastasis
Asexual reproduction _____.
produces offspring genetically identical to the parent
Spindle fibers attach to kinetochores during _____.
prometaphase
Chromosomes become visible during _____.
prophase
In a human skin cell that is going through the cell cycle, when do the centrosomes separate?
prophase
In telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in __________.
prophase
Synapsis occurs during _____.
prophase I
During _____ a spindle forms in a haploid cell.
prophase II
Checkpoints in the cell cycle control system __________.
regulate the cell cycle through a series of stop and go signals
Which of the following does NOT occur during mitosis?
replication of chromosomes
The centromere is a region in which __________.
sister chromatids are attached to one another in prophase
Meiosis II is similar to mitosis in that __________.
sister chromatids separate during anaphase.
Cytokinesis often, but not always, accompanies _____.
telophase
Which of the following phases of mitosis is essentially the OPPOSITE of prometaphase in terms of the nuclear envelope?
telophase
At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids.
telophase I
DNA replication occurs in __________.
the S phase of interphase in both somatic and reproductive cells
One event occurring during prophase is __________
the beginning of the formation of a spindle apparatus
One event occurring during prophase is __________.
the beginning of the formation of a spindle apparatus
The decline of MPF activity at the end of mitosis is due to
the degradation of cyclin.
During _____ both the contents of the nucleus and the cytoplasm are divided.
the mitotic phase
During binary fission in a bacterium, __________.
the origins of replication move apart
During prophase a homologous pair of chromosomes consists of _____.
two chromosomes and four chromatids
If we continued to follow the cell lineage from question 99, then the DNA content of a single cell at metaphase of meiosis II would be ________.
x
Which event or events occur during anaphase?
A spindle made of microtubules is present, the centrioloes are at opposite poles, identical chromatids are moved to opposite poles, and the centromeres divide
During which stage of the cell cycle do sister chromatids separate?
Anaphase
In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle?
Cytokinesis
When a cell in S phase is fused with a cell in G1, __________.
DNA synthesis begins immediately in the original G1 nucleus
Which of the following is involved in the binary fission of most bacteria?
Distribution of a copy of the single parental chromosome to each daughter cell
_____ is a carcinogen that promotes colon cancer.
Fat
For what purpose(s) might a karyotype be prepared?
For prenatal screening, to determine if a fetus has the correct number of chromosomes, to determine whether a fetus is male or female, and to detect the possible presence of chromosomal abnormalities such as deletions, inversions, or translocations
The region of a chromosome holding the two double strands of replicated DNA together is called __________.
a centromere
The region of a chromosome in which the two double strands of replicated DNA are held together is called __________.
a centromere
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
A human cell containing 22 autosomes and a Y chromosome is _________.
a sperm
During binary fission in a bacterium __________.
the origins of replication move apart
