Biology Cell Cycle
You are a medical student and are reviewing a case study about a past patient. The patient was 4 feet 8 inches tall at age 38, was unable to have children, and had cognitive impairments. The patient also had an irregular number of chromosomes. What diagnosis would you give the patient? chronic myelogenous leukemia Klinefelter syndrome Turner syndrome Down syndrome
Turner Syndrome
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 in one of the grasshopper daughter cells? View Available Hint(s) 200 units 100 units 50 units 400 units
100 units
According to the graph, at what maternal age is the incidence of Down syndrome equal to five times the incidence at age 40? (the figure shows the incidence of Down Syndrome as a function of mother's age. There is 1 defected infant per 1000 births, when mothers are 20 years old. Then the incidence increases to 2 at 25 years, then to 3 at 30 years, 4 at 35 years, 10 at 40, 30 at 45, and 80 at 50 years) about 29 or 30 about 35 or 36 about 44 or 45 about 46 or 47
about 46 or 47
As a patch of scraped skin heals, the cells fill in the injured area but do not grow beyond that. This is an example of anchorage independence. density-dependent inhibition. density-independent inhibition. growth factor inhibition.
density- dependent inhibition
You see a cell with several nuclei and you know that something is different about cell division. What is the most likely explanation? nondisjunction failure of cytokinesis following mitosis failure of sister chromatids to separate failure of homologous chromosomes to separate
failure of cytokinesis following mitosis
Consider the photograph shown below. You can determine this is a plant cell rather than an animal cell because it has __________. (There is a micrograph of dividing cells.) separated duplicated chromosomes during mitosis formed a cleavage furrow microtubules formed a cell plate
formed a cell plate
A human bone marrow cell in the prophase stage of mitosis contains 46 chromosomes. Therefore, there are a total of __________ sister chromatids in this cell. 23 46 23 or 46, depending on whether you look at the beginning or end of prophase 92
92
The kinetochores are __________. A)sites at which microtubules attach to chromosomes B)the primary centromere structures that maintain the attachment of the sister chromatids prior to mitosis C)found as each spindle interlocks at the cell's equator and then moves apart, causing the cell to elongate D)used to organize tubulin into elongated bundles called spindle fibers
A)sites at which microtubules attach to chromosomes
Which of the following statements regarding prokaryotes is false? A)In prokaryotes, daughter chromosomes are separated by an active movement away from each other and the growth of a new plasma membrane between them. B)Prokaryotic chromosomes are more complex than those of eukaryotes. C)Prokaryotic cells are generally smaller and simpler than eukaryotic cells. D)Most prokaryotes reproduce by binary fission.
B)Prokaryotic chromosomes are more complex than those of eukaryotes.
Which of the following statements regarding mitosis and meiosis is true? A)Mitosis takes place in your gametes, whereas meiosis takes place in your somatic cells. B)In metaphase of mitosis and metaphase I of meiosis, homologous chromosomes separate. C)Sister chromatids separate during anaphase of mitosis and anaphase II of meiosis. D)Independent orientation occurs during metaphase of mitosis and metaphase II of meiosis.
C)Sister chromatids separate during anaphase of mitosis and anaphase II of meiosis.
You have two flasks (labeled A and B) that each contain an equal population of normal animal cells. You place flask A in a machine called a shaking incubator, which shakes the flask at 37°C and keeps the cells moving so as to not allow them to adhere to the bottom of the flask. Flask B is allowed to sit in an incubator (without shaking) at 37°C. If you let the cells in each flask grow for a week, which of the following results are you most likely to observe? A)The cells in both flasks A and B will have not grown at all. B)The cells in both flasks A and B will have grown significantly. C)The cells in flask B will have grown significantly, but the cells in flask A will have not grown at all. D)The cells in flask A will have grown significantly, but the cells in flask B will have not grown at all.
C)The cells in flask B will have grown significantly, but the cells in flask A will have not grown at all
This image shows a step that is partway through meiosis. (An image of two cells side by side. Each contains two unduplicated chromosomes. In the cell on the left, one chromosome is blue, and the other chromosome is a mix of blue and red. In the cell on the right, one chromosome is a mix of red and blue, and other is red.) Which of the following events have not yet occurred? Select all that apply. A)separation of homologous chromosomes into distinct cells B)formation of chiasmata C)production of four haploid gametes D)crossing over E)separation of sister chromatids into distinct cells
C)production of four haploid gametes E)separation of sister chromatids into distinct cells
When examining cells in the laboratory, you notice that a particular cell has half as much DNA as the surrounding cells. This observation can be explained if this cell's cell cycle halted at checkpoint _____. M phase G0 G2 G1
G1
Below are three statements. Classify them as examples of independent orientation, crossing over, or random fertilization. I: The formation of a zygote from an egg and a sperm is an unpredictable event. II: Random combinations of paternal and maternal chromosomes end up in gametes. III: An allele on the paternal chromosome 18 ends up on the maternal chromosome 18. I: random fertilization; II: random fertilization; III: independent orientation I: random fertilization; II: independent orientation; III: crossing over I: independent orientation; II: random fertilization; III: crossing over I: random fertilization; II: crossing over; III: independent orientation
I: random fertilization; II: independent orientation; III: crossing over
During _____ both the contents of the nucleus and the cytoplasm are divided. mitosis the mitotic phase G2 G1 S
The mitotic phase
A pair of sex chromosomes found in a human male is most like a bride and groom. a pair of blue jeans. a knife, fork, and spoon. identical twins.
a bride and groom
A cell is treated with a drug that prevents the formation of vesicles. Which of the following processes depends on the formation of vesicles and would therefore be blocked? cytokinesis in a plant cell separation of eukaryotic chromosomes at anaphase cytokinesis in an animal cell alignment of eukaryotic chromosomes at the metaphase plate
cytokinesis in a plant cell
Independent orientation of chromosomes at metaphase I results in an increase in the number of gametes. sex chromosomes. possible combinations of characteristics. homologous chromosomes.
possible combinations of characteristics
In the telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in _____. interphase prophase anaphase metaphase
prophase
A technique called flow cytometry is used by scientists and researchers to count or sort cells based on specific properties. By labeling cellular DNA with a fluorescent dye, flow cytometry can sort cells based on the amount of DNA present, thereby making it possible to distinguish between cells that are in different stages of the cell cycle. Flow cytometry is especially useful to the medical community because it can help with the diagnosis of certain types of cancers. Below is a typical set of data that you might obtain when running a flow cytometry experiment using a sample of healthy skin cells. Use this figure to help you answer the following question. (The figure shows the result of flow cytometry analysis. It shows the number of cells as a function of fluorescence. Peak A is very high and narrow. Peak B is wide but low. Peak C is narrow and low, but higher than Peak B.) If you used flow cytometry to sort a sample of cancerous cells that have been treated with a drug to prevent them from replicating their DNA, what peaks would you expect to see on the resulting flow cytometry data set? A and B only A only A, B, and C C only
A Only
Plants grow taller through mitosis at the tips of their shoots (above ground) and at the tips of their roots (below ground). Here are two samples of tissue taken from a grass plant, one from the tip of the root and one from the mid part of the plant. Interphase S1- 74% S2-98% Prophase S1-18% S2-0.5% Metaphase S1- 4% S2-0.2% Anaphase S1-2% S2-0.1% Telophase S1-1% S2-0.1% What can you conclude from these data? A)Sample 2 is likely from tissue in the middle of the plant because fewer cells are in any mitotic stage. B)Sample 2 is likely from tissue in the middle of the plant because there are fewer cells in telophase than are in prophase C)Sample 1 is likely from tissue in the middle of the plant because most cells are in interphase. D)Sample 1 is likely from tissue in the middle of the plant because fewer cells are in any mitotic stage than in sample 2.
A)Sample 2 is likely from tissue in the middle of the plant because fewer cells are in any mitotic stage.
A technique called flow cytometry is used by scientists and researchers to count or sort cells based on specific properties. By labeling cellular DNA with a fluorescent dye, flow cytometry can sort cells based on the amount of DNA present, thereby making it possible to distinguish between cells that are in different stages of the cell cycle. Flow cytometry is especially useful to the medical community because it can help with the diagnosis of certain types of cancers. Below is a typical set of data that you might obtain when running a flow cytometry experiment using a sample of healthy skin cells. Use this figure to help you answer the following question. (The figure shows the result of flow cytometry analysis. It shows the number of cells as a function of fluorescence. Peak A is very high and narrow. Peak B is wide but low. Peak C is narrow and low, but higher than Peak B.) Which peak corresponds to cells in G1? In S phase? In G2? A: G1; B: G2; C: S A: S; B: G1; C: G2 A: G1; B: S; C: G2 A: G2; B: S; C: G1
A: S; B: G1; C: G2
Mr. and Mrs. Smith have three sons in elementary school. Two of their children are progressing normally, but their youngest son, Charles, has been much slower than his siblings in developing speech and language skills. His parents are concerned that he has a learning disability and decide to investigate further. Since some learning disabilities can be genetically based, their pediatrician recommends a chromosomal analysis. The results show that Charles has a trisomy of the sex chromosomes, diagnosed as XYY. A mistake during sperm formation resulted in an extra copy of the Y chromosome. The extra copy was passed on to Charles during fertilization. Most often, this chromosomal change causes no unusual physical features or medical problems, but those with trisomy of the sex chromosomes may have a higher-than-normal risk of delays in learning development. During which stage of meiosis could this mistake have occurred? telophase I telophase II prophase I anaphase II
Anaphase II
In comparing a frog cell in metaphase of mitosis with one in metaphase I of meiosis, how would tell you which was which? A)In meiosis, the chromosomes would be unduplicated (single-stranded) and in mitosis, they would be double-stranded (made up of sister chromatids). B)Unlike mitosis, in meiosis each chromosome would be opposite its homolog. C)Unlike meiosis, in mitosis each chromosome would be paired with its homolog. D)In mitosis, the chromosomes would be unduplicated (single-stranded) and in meiosis, they would be double-stranded (made up of sister chromatids).
B)Unlike mitosis, in meiosis each chromosome would be opposite its homolog.
A karyotype is most like A)a map showing the hidden location of buried treasure. B)photographs of every couple at a high school prom. C)a movie showing the stages of the reproductive cycle of a beetle. D)the answer key to a multiple-choice exam.
B)photographs of every couple at a high school prom
A technique called flow cytometry is used by scientists and researchers to count or sort cells based on specific properties. By labeling cellular DNA with a fluorescent dye, flow cytometry can sort cells based on the amount of DNA present, thereby making it possible to distinguish between cells that are in different stages of the cell cycle. Flow cytometry is especially useful to the medical community because it can help with the diagnosis of certain types of cancers. Below is a typical set of data that you might obtain when running a flow cytometry experiment using a sample of healthy skin cells. Use this figure to help you answer the following question. (The figure shows the result of flow cytometry analysis. It shows the number of cells as a function of fluorescence. Peak A is very high and narrow. Peak B is wide but low. Peak C is narrow and low, but higher than Peak B.) Which peak represents cells that contain the most DNA? A B C It cannot be determined from this figure.
C
Oncologists (medical doctors who treat cancer patients) routinely take biopsies (samples) of tissue from patients to determine whether the tissue is cancerous or not. What would be the best technique to use to determine whether cells from the tissue sample are cancerous? A)Measure the amount of DNA in G1 in the cells from the tissue sample and compare it to the amount of DNA in G2 in noncancerous cells from the patient. B)Add cells from the tissue sample to a rat to see whether the rat develops cancer or not. C)Add cells from the tissue sample to a cell culture dish and compare their growth against a sample of noncancerous cells from the patient. D)Count the number of chromosomes in the cells from the tissue sample and compare to the number of chromosomes in noncancerous cells from the patient.
C)Add cells from the tissue sample to a cell culture dish and compare their growth against a sample of noncancerous cells from the patient.
Crossing over of chromosomes during meiosis shuffles parental chromosomes, resulting in a genetically unique child. Select the three true statements about crossing over. A)Chromosomes from the egg and the sperm undergo crossing over immediately after fertilization occurs. B)Chiasmata in nonsister chromatids decrease the genetic variability produced during crossing over. C)During prophase I of meiosis I, homologous paternal and maternal chromosomes line up at the metaphase plate. D)During meiosis II, sister chromatids separate into four different gametes. E)A hybrid chromosome that has crossed over will contain pieces of both the maternal and paternal chromosomes.
C)During prophase I of meiosis I, homologous paternal and maternal chromosomes line up at the metaphase plate. D)During meiosis II, sister chromatids separate into four different gametes. E)A hybrid chromosome that has crossed over will contain pieces of both the maternal and paternal chromosomes.
You are observing a single cell under a microscope. You go home for the night, and the next day you see four cells. The four cells look similar, and when you stain them with a dye that binds to DNA they all appear to contain the same amount of DNA as the original cell. What likely happened overnight? A)The single cell divided once to form four new cells via sexual reproduction. B)The single cell divided to form two new cells, and the two new cells each divided to form four total cells, all by sexual reproduction. C)The single cell divided to form two new cells, and the two new cells each divided to form four total cells, all by asexual reproduction. D)The single cell divided once to form four new cells via asexual reproduction.
C)The single cell divided to form two new cells, and the two new cells each divided to form four total cells, all by asexual reproduction.
In some plants such as mosses and ferns, there is a multicellular stage in the life cycle that is haploid and a different stage that is diploid. What can you conclude from this? A)Meiosis must happen over and over to produce as many haploid cells for a multicellular haploid plant. B)The haploid cells must undergo twice as much mitosis in order to produce a diploid stage. C)Haploid cells must undergo meiosis to form gametes. D)Haploid cells must undergo mitosis to produce a multicellular haploid stage.
D)Haploid cells must undergo mitosis to produce a multicellular haploid stage.
Mr. and Mrs. Smith have three sons in elementary school. Two of their children are progressing normally, but their youngest son, Charles, has been much slower than his siblings in developing speech and language skills. His parents are concerned that he has a learning disability and decide to investigate further. Since some learning disabilities can be genetically based, their pediatrician recommends a chromosomal analysis. The results show that Charles has a trisomy of the sex chromosomes, diagnosed as XYY. A mistake during sperm formation resulted in an extra copy of the Y chromosome. The extra copy was passed on to Charles during fertilization. Most often, this chromosomal change causes no unusual physical features or medical problems, but those with trisomy of the sex chromosomes may have a higher-than-normal risk of delays in learning development. The problem that occurred during meiosis in sperm formation was A)formation of diploid sperm. B)an inversion of the X chromosome, preventing the pairing of sex chromosomes. C)failure of the second meiotic division to take place. D)nondisjunction involving a Y chromosome.
D)nondisjunction involving a Y chromosome.
Which of these phases encompasses all of the stages of mitosis? (There is a diagram which represents the cell cycle. M phase is labeled A. Cytokinesis is labeled B. Interphase is labeled C. It contains 3 stages. S phase is labeled D. A and B stages together are included in the stage labeled E. D A C E B
E
Why are individuals with an extra chromosome 21, which causes Down syndrome, more numerous than individuals with an extra chromosome 3 or chromosome 16? There are probably more genes on chromosome 21 than on either chromosomes 3 or 16. Down syndrome results in more serious symptoms than either trisomy 3 or trisomy 16. Extra copies of the other somatic chromosomes are probably fatal. Nondisjunction of chromosomes 3 and 16 probably occurs more frequently.
Extra copies of the other somatic chromosomes are probably fatal.
A skin cell of a red fox has 34 chromosomes. You look at the cell under a microscope and see that it has 34 chromosomes and one nucleus. Several hours later, you look at the same cell again and see that it has double the amount of DNA and one nucleus. A little while later, you see that it has 68 chromosomes and two nuclei. What stage of the cell cycle was this cell in when you viewed it at each time point? First view: G0; second view: G2; third view: telophase First view: G1; second view: metaphase; third view: cytokinesis First view: S; second view: prophase; third view: cytokinesis First view: G1; second view: G2; third view: telophase
First view: G1; second view: G2; third view: telophase
During _____ the cell grows and replicates both its organelles and its chromosomes. cytokinesis interphase S mitosis G1
Interphase
Jacobsen syndrome, which can cause heart defects, intellectual deficiencies, and bleeding disorders, is caused by a deletion of the terminal end of chromosome 11. What method could you use to determine whether an individual has Jacobsen syndrome? Count the number of chromosomes present. Look at a person's skin cells in G1 under a light microscope. Perform a karyotype using a person's white blood cells. Place a person's red blood cells in culture to see if they grow.
Perform a karyotype using a person's white blood cells
Many cancer drugs known as "antimitotics" target microtubules. What is the first stage of mitosis at which these drugs are likely to have an effect? anaphase telophase metaphase prophase
Prophase
What event will immediately follow the event shown in the following image? (The figure shows a micrograph of a large cell. It has thick walls and two equal large condensed dark structures in it. There's a thin incomplete septum between these structures.) The cell will divide into two plant cells. The cell will enter metaphase. The cell will divide into two animal cells. The cell will enter prophase.
The cell will divide into two plant cells.
You and your lab partner are observing a cell under a microscope, but you do not know whether it is a eukaryote or a prokaryote. Which of the following observations regarding the chromosomes would you use to immediately conclude that the cell is a eukaryote? The chromosomes are circular in structure. The chromosomes are housed in a membrane-enclosed nucleus. The chromosomes are very simple in structure. The chromosomes contain very few proteins.
The chromosomes are housed in a membrane-enclosed nucleus.
What would be the immediate consequence of destroying a cell's centrosomes? Sister chromatids would lose their centromeres. The mitotic spindle would not form. The nuclear envelope could never re-form. The nuclear envelope would never break down.
The mitotic spindle would not form.
Which of the following variations of the sentence "Where is the cat?" is most like a chromosomal inversion? Where is cat? Where is the the cat? Where the is cat? Where is cat the the cat?
Where the is cat?
You are asked to culture an unidentified sample of animal tissue. You notice that the cells seem to fail to exhibit density-dependent inhibition. The source of this tissue sample is most likely a cancerous tumor. liver from a cow. skin from a human. sperm-producing tissue of the testis
a cancerous tumor
Which of the following shows the greatest promise as a cancer chemotherapy agent? a drug that interferes with organismal cellular respiration a drug that prevents tetrad formation a drug that prevents mitotic spindle from forming a drug that prevents crossing over
a drug that prevents mitotic spindle from forming
In the laboratory, cancer cells fail to show density-dependent inhibition of growth in cell culture. What is one explanation that could account for this? Cancer cells are unable to attach to a surface and grow. Cancer cells continuously secrete growth factors into the cell culture medium. Cancer cells continue to die at a rate that is equal to their growth. Cancer cells have inactive receptors for growth factors.
cancer cells continuously secrete growth factors into the cell culture medium
In anaphase I, __________. the sister chromatids move toward opposite poles homologous chromosomes move toward opposite poles the sister chromatids move randomly toward either pole homologous chromosomes move randomly toward either pole
homologous chromosomes move toward opposite poles
Place the events of meiosis in the proper order. four haploid gametes are produced crossing over occurs sister chromatids separate homologous chromosomes pair homologous chromosomes separate nonsister chromatids form chiasmata
homologous chromosomes pair nonsister chromatids form chiasmata crossing over occurs homologous chromosomes separate sister chromatids separate four haploid gametes are produced
In some organisms such as certain fungi and algae, cells undergo mitosis repeatedly without subsequently undergoing cytokinesis. What would be the consequence of this? large cells containing many nuclei a decrease in chromosome number an inability to duplicate DNA division of the organism into many cells, most lacking nuclei
large cells containing many nuclei
What is the stage of cell division in a diploid organism if you see seven chromosomes, each consisting of a pair of sister chromatids? meiosis I anaphase meiosis II prophase mitosis prophase mitosis anaphase
meiosis II prophase
If scientists studying cancer could understand how to promote cell division in cells that do not ordinarily divide, this might help people who had injuries involving bone cells. muscle or nerve cells. skin cells. intestinal cells.
muscle or nerve cells
You are studying chromosomal movement in a frog species whose haploid number is 3. What will you see in meiosis I prophase of this cell? three chromosomes, each made up of sister chromatids (double-stranded) three chromosomes, each single-stranded (unduplicated) six chromosomes, each made up of sister chromatids (double-stranded)
three chromosomes, each single-stranded (unduplicated)
At the end of telophase I of meiosis, as cytokinesis occurs, there are __________. one haploid ovum and three polar bodies two haploid cells four haploid cells two diploid cells
two haploid cells
Looking into your microscope, you spot an unusual cell. Instead of the typical rounded cell shape, the cell has a very narrow middle separating two bulging ends. It sort of looks like the number 8! You realize that this cell is in the G1 phase of interphase. in the S phase of interphase. about to undergo mitosis. undergoing cytokinesis.
undergoing cytokinesis.