bio ch 8,9,10
A positive genetic test for telomerase indicates that
a cell is probably cancerous
Cytokinesis usually, but not always, follows mitosis. If a cell undergoes mitosis and not cytokinesis, this would result in
a cell with two or more nuclei
An oncogene is more likely to lead to cancer than a mutant tumor suppressor gene because
a gain of function mutation in an oncogene need only occur in one allele before it disrupts control of the cell cycle.
A woman inherits a mutant BRCA1 allele from her mother. She has an increased risk of developing breast cancer because
a mutation in her normal BRCA1 allele may lead to cancer, whereas a normal individual would have to acquire two mutations (one in each allele) to develop cancer.
Cells grown in a petri dish tend to divide until they form a thin layer covering the bottom of the dish. If cells are removed from the middle of the dish, the cells bordering the open space will begin dividing until they have filled the empty space. What does this experiment show?
all answers are valid and correct
The figure below shows a cell in the mitotic stage of (pulling apart from middle)
anaphase
For the figure shown here, indicate the correct stage of meiosis and diploid chromosome number. pulling apart 4 on each side
anaphase I, 2n=8
Which of the following phases results in separation of sister chromatids into daughter chromosomes?
anaphase II and anaphase of mitosis
Rick has a high incidence of cancer in his family. Four of the following five statements are preventative measures to avoid cancer. Which of the following is not correct?
avoid a high-fiber, low-sodium diet
Proteins that are involved in the regulation of the cell cycle, and that show fluctuation in concentration during the cell cycle, are called
cyclins
Which of the diagrams best illustrates the appearance of a chromosome or chromosome pair at the end of prophase I?
diagram 2
Which of the diagrams represent a chromosome or chromosome pair in a cell at the end of prophase II?
diagram 4
The figure below shows a cell in which stage of the cell cycle? (centrioles in centrosomes, nucleolus, chromatin, nuclear envelope, plasma membrane)
interphase
DNA and histones form bead-like globules known as
nucleosomes
a dyad consists of
one duplicated chromosome consisting of two sister chromatids.
Which of the following processes and products are paired correctly?
oogenesis - 1n gamete
Which of the following does not occur twice during meiosis?
pairing of homologous chromosomes
Which of the following is a correct match?
separation of sister chromatids - anaphase II
The structures labeled "d" in the following figure are called
sister chromatids
The spindle serves two roles in mitotic cell division. These are to separate the
sister chromatids and to elongate the cell.
Which lifestyle choice is responsible for 90% of the cases of lung cancer among men?
smoking
Susan went to an oncologist because some cancerous cells had been detected within her breast tissue. Which of the following is not a warning signal for cancer?
some cells were found to be in interphase
The term metastasis refers to the fact that cancer cells tend to
spread
A proto-oncogene differs from a tumor suppressor gene because a proto-oncogene
stimulates mitosis in a normal cell, whereas a tumor suppressor gene inhibits mitosis.
If cancer is discovered at an early stage, which treatment method is most often used?
surgery
All of the following occur during the latter stages of mitotic prophase except the
synthesis of DNA
Embryonic cells and cancer cells are similar because
telomerase is active
Ben was looking at onion root tip cells under the microscope in biology class. He saw one cell that had two nuclei within it. What stage of the cell cycle was this cell in?
telophase/cytokinesis
Cytokinesis in plants occurs as ________ and in animals as ________.
the Golgi apparatus produces membrane-bound vesicles filled with materials to make the cell wall; actin fibers pull the membrane inward until the two sides touch
A mutation results in a cell that no longer produces a normal protein kinase for the M-phase checkpoint. Which of the following would likely be the immediate result of this mutation?
the cell would never leave metaphase
All of the following statements are true about mitosis except
the cells arising from mitosis contain only half of the necessary genetic material.
The possibility of Down syndrome increases as the mother's age increases because
the possibility of nondisjunction increases
cancer occurs when
the regulation of the cell cycle is lost and uncontrolled cell division occurs.
If a cell stops at the G1 checkpoint, this is most likely due to what problem?
there is DNA damage
When a portion of a chromosome breaks off and attaches to a different chromosome, this is called a
translocation
A protein that promotes apoptosis would be considered a(n)
tumor suppressor
A tetrad is composed of
two chromosomes with two sister chromatids each.
The G2 checkpoint prevents the cell cycle from continuing until
DNA is completely replicated and damage to DNA can be repaired.
A cell is inhibited during the S phase of its cycle. It will not reproduce due to lack of
DNA synthesis
Inheritance of mutant forms of some genes may lead to a predisposition to develop cancer. Which of the genes listed below has not been linked to hereditary forms of cancer?
DScam
Armadillos have a diploid chromosome number of 64. At prophase I, an armadillo's cell would have ________ tetrads present.
32
During prophase I, a diploid organism contains how many copies of each gene?
4
If a cell has 46 chromosomes at the beginning of mitosis, then at the end of anaphase there would be a total of
92 chromosomes
In each gamete following telophase II, how many copies of each gene is/are present?
1
A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA in the nucleus. Those cells would have ________ picograms at the end of the S phase and ________ picograms at the end of G2.
16;16
During G1 stage of interphase, a diploid organism contains how many copies of each gene?
2
During prophase II, a diploid organism contains how many copies of each gene?
2
If there are 20 centromeres in a cell, how many chromosomes are there?
20
Cells grown in a petri dish tend to divide until they form a thin layer covering the bottom of the dish. Which of the following statements explains why this occurs?
Cell division can be inhibited by the proximity of other cells of the same type, a process called contact inhibition.
Which of the following organelles would be abundant and in close proximity to the cell plate in a plant cell undergoing cytokinesis?
Golgi apparatus
Which of the following statements is correct? in relation to meiosis
Meiosis involves two divisions and produces four nonidentical daughter nuclei.
Which items in the following pairs are correctly matched?
S phase- DNA replication
A tumor suppressor gene undergoes a mutation that causes it to lose its normal function. What would be the most likely result of this mutation?
The cell no longer responds to signals that cause it to stop dividing or undergo apoptosis
What would occur in a cell if the production of cyclins halted during the cell cycle?
The cell would remain in the G2 phase and would not enter into mitosis.
How do the daughter cells at the end of mitosis and cytokinesis compare to 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.
Which statement best describes how the members of a tetrad are separated during meiosis I?
The two homologous chromosomes of a tetrad separate into different daughter nuclei.
Refer to the figure below. Differentiated cells, such as nerve cells, would be in which of the following stages of the cell cycle?
b
apoptosis
can be used to remove damaged or malfunctioning cells.
Angiogenesis contributes to carcinogenesis because it
causes blood vessels to grow into the tumor.
Which of the following is not a characteristic of cancer cells? in relation to phases
cells that spend 90% of their lifetime in interphase
The structure labeled "c" in the following figure is called the
centromere
What is the structure that holds together the two sister chromatids that form a chromosome?
centromere
Which cancer therapy can lead to side effects such as nausea and hair loss?
chemotherapy
What structure is formed by two sister chromatids being held together by a centromere?
chromosome
The looping of DNA around histone proteins
condenses a large amount of DNA so that it can fit into the cell.
One major difference between meiosis I and meiosis II is that
crossing-over occurs in prophase of meiosis I but not in prophase of meiosis II.
A translocation may lead to cancer if it
disrupts control of expression of genes that regulate the cell cycle.
A mutation that causes an increase in function in a tumor suppressor gene would not likely cause cancer because a tumor suppressor protein
does not promote cell division
When during the cell cycle are chromosomes visible?
during mitosis
Nuclear division is represented in the figure below by the letter
e
Which of the following is not a characteristic of cancer cells? exhibits ____
exhibit contact inhibition
During meiosis I, the homologous chromosomes of a tetrad
face opposite spindle poles.
Which of the following lists is in the correct order, from the least inclusive to the most inclusive?
gene - allele - chromosome
during crossing-over,
genetic material is exchanged between nonsister chromatids, resulting in new combinations of alleles.
The presence of which protein is required in order for chromatin to compact correctly within the nucleus?
histone
Metaphase II is more similar to metaphase of mitosis than to metaphase I because
in metaphase II, dyads align separately at the spindle equator.
Multicellular organisms undergo mitotic cell division to
increase the size of the organism
Which of the following processes does not contribute to creating genetic variability in the offspring?
interkinesis
While Jeff was looking under the microscope at cells in different stages of mitosis, he commented on the fact that many cells were in the same stage. If you were looking under the compound light microscope at an onion root tip, in what stage of the cell cycle would the majority of the cells be?
interphase
Which is not a correct association?
interphase - shortest stage of the cell cycle
Which of the following statements is correct regarding the events of the cell cycle?
interphase consists of G1, S, and G2
During which stage of the cell cycle do the chromosomes duplicate?
interphase; S
Rebecca found out that she has a mass of dividing cells called a tumor in her ovaries. She has had tests and is returning to the doctor. Which of the following would be the best news that Rebecca could receive from her doctor?
it is a benign tumor
in the human life cycle,
meiosis produces haploid gametes, and fertilization creates a diploid cell that divides by mitosis to produce a new individual.
The figure below shows a cell in the mitotic stage of (lined up in middle)
metaphase
For the figure shown here, indicate the correct stage of meiosis and diploid chromosome number. lined up in middle 2 on each side
metaphase I, 2n=4
If tumor cells have a faulty, nonfunctional proteinase, they will be unable to undergo which of the following processes?
metastasis
The mitotic spindle is composed of ________ and grows from the ________ toward the center of the cell.
microtubules; centrosome
Some multicellular organisms, like the hydra, use asexual reproduction to produce a bud that leads to a new organism. This means that they are using
mitotic division to create new cells that become a new organism.
The failure of sister chromatids to separate during meiosis is called
nondisjunction
Cells that do not receive the correct signals to move from G1 into S phase will enter G0 and therefore will
not undergo mitotic division unless it later receives the go-ahead signal.
Susan was examining a cell under the microscope and noticed the formation of a cell plate in the midline of the cell and the formation of nuclei at opposite poles of the cell. The cell under examination was most likely a(n)
plant cell undergoing cytokinesis
Plant cells and animal cells differ in cytokinesis because
plant cells need to build a cell wall, while animal cells do not.
Some of the drugs used in chemotherapy work by
preventing spindle formation
Unicellular organisms undergo mitotic division to
produce new organisms
The drug chloral hydrate prevents elongation of microtubules by preventing the addition of new subunits to the growing end. During which stage of mitosis would chloral hydrate be most harmful?
prophase
The figure below shows a cell in the mitotic stage of (early mitotic spindle, centrosome, centromere, chromosome with two sister chromatids)
prophase
For the figure shown here, indicate the correct stage of meiosis and the diploid number of the cell.
prophase II, 2n=4
Which of the following represents the phases of mitosis in their proper sequence?
prophase, metaphase, anaphase, telophase
Cancer is a disorder in which some cells have lost the ability to control their
rate of cell division
