Cell Cycle
During _____ a spindle forms in a haploid cell.
Prophase II
The second division of meiosis
prevents a doubling of chromosome copies at fertilization.
Which of the following organisms would be most similar to humans in a study that involved the response of cancer cells to various medications?
primates
Spindle fibers attach to kinetochores during _____.
prometaphase
Which processes lead to most genetic variation in sexually reproducing organisms?
random fertilization crossing over independent assortment of chromosomes in meiosis
Which of the following occurs during S phase?
replication of the DNA
At the milestone that defines anaphase, the chromosomes
separate
Meiosis II is similar to mitosis in that
sister chromatids separate during anaphase
Cytokinesis often, but not always, accompanies _____.
telophase
At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids.
telophase I
At the end of _____ and cytokinesis there are four haploid cells.
telophase II
Which of these cells is (are) haploid?
Meiosis I and Meiosis II
Synapsis occurs during _____.
Prophase I
During meiosis I in humans, one of the daughter cell receives
a mixture of maternal and paternal chromosomes
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.
Centromeres divide and sister chromatids become full-fledged chromosomes during _____.
anaphase
During _____ sister chromatids separate.
anaphase II
During meiosis, the sister chromatids separate during
anaphase II
At the milestone that defines telophase, the chromosomes
are at opposite poles
The members of a homologous pair of chromosomes
are identical in size and appearance
Since 1991, deaths from breast and colorectal cancer in the United States are down 35%. What is the main reason for this?
better screening
Based on the information in the video, which of the following correctly answers these three questions: What was the leading cause of death in the United States in the early 1970s? What is the leading cause of death in the United States today? What is predicted to be the leading cause of death in the United States 10 years from now?
cancer; cardiovascular disease; cancer
Which of the following statements best describes homologous chromosomes?
carry information for the same trait
In plant cells, cytokinesis is accomplished by the formation of a(n)
cell plate
The total DNA content of each daughter cell is reduced during meiosis because
chromosomes do not replicate between meiosis I and II
Which of these is NOT a carcinogen?
cigarette smoke testosterone UV light fat ALL OF THE ABOVE
One difference between cancer cells and normal cells is that cancer cells
continue to divide even when they are tightly packed together.
After the centromeres separate during mitosis, the chromatids, now called _____ move toward opposite poles of the spindle.
daughter chromosomes
All zygotes are
diploid
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.
Chromatin condenses to form discrete, visible chromosomes
during prophase
Chromosomes become visible during _____.
prophase
The number of daughter chromosomes in human cell (diploid 46) in anaphase II of meiosis is
46
Diploid cells of the fruit fly Drosophila have ten chromosomes. How many chromosomes does a Drosophila gametes have?
5
Which of the following is closest to the current average annual death rate from cancer in the United States?
580 thousand
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 will be
2x
A diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produces gametes containing _____ chromosomes.
16
When did the United States declare a "war on cancer" by passing the National Cancer Act?
1971
In human gamete production there is an average of _____ crossover events per chromosome pair.
2-3
Normal human gametes carry _____ chromosomes.
23
Homologous chromosomes migrate to opposite poles during _____.
Anaphase I
The molecules that make up a chromosome are _____ and _______
DNA; proteins
_____ is a carcinogen that promotes colon cancer.
Fat
Which of the following best describes the advantages of the personalized care technique described in the video?
Fruit flies make excellent models because we can create a strain of flies with a specific type of tumor, then raise thousands of flies in order to test the effects of medications.
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
During _____ chromosomes align single file along the equator of a haploid cell.
Metaphase II
Which of these phases encompasses all of the stages of mitosis but no other events?
Mitosis
Which of the following does not occur during mitotic prometaphase
Synapsis of homologous chromosomes
How does a nucleus in G2 differ from a nucleus in G1
The G2 nucleus has twice the amount of DNA as the G1 nucleus
A bacterial cell gives rise to two genetically identical daughter cells by a process known as
fission
Meiosis II typically produces _____ cells, each of which is _____.
four ... haploid
During mitotic anaphase, chromosomes migrate
from the equatorial plate toward the poles
Meiosis can occur
in all sexually reproducing organisms
During _____ the cell grows and replicates both its organelles and its chromosomes.
interphase
Nucleoli are present during _____.
interphase
The process of synapsis and the formation of chiasmata
involve reciprocal exchange of chromosomal sections involve the recombination of DNA on homologous chromosomes bring about an increase in genetic variation provide evidence that an exchange of genetic material has occured ALL OF THE ABOVE
Which of the following statements about the human X chromosomes is correct?
is present in every gametic cell of males and females
At the milestone that defines metaphase, the chromosomes
line up at the equatorial plate
Human gametes are produced by _____.
meiosis
The two homologs of a pair move toward opposite poles of a dividing cell during
meiosis I.
Homologous pairs of chromosomes are lined up independently of other such pairs during _____.
metaphase I
The mitotic spindle is composed of
microtubules
Crossing over, resulting in an increase in genetic variation, occurs between _____.
nonsister chromatids of homologous chromosomes
The decline of MPF activity at the end of mitosis is due to
the degradation of cyclin.
Why is the "personalized care" plan described in the video, in which treatments are tailored for each individual, much more promising than previous treatment plans?
the genetic mutations that cause cancer vary from patient to patient
During _____ both the contents of the nucleus and the cytoplasm are divided.
the mitotic phase
Meiosis I produces _____ cells, each of which is _____.
two ... haploid
At the end of the first meiotic division, each chromosome consists of
two chromatids
The products of mitosis are
two genetically identical nuclei
If the DNA content of a diploid cell is x in the G1 phase of the cell cycle and 2x at metaphase of meiosis I, then the DNA content of the same cell at metaphase of meiosis II will be
x