Biology Ch. 8
How many generations does it take to develop a new plant species by polyploidy? 10 2 1 20
1
Part complete Asexual reproduction requires ________ individual(s), whereas sexual reproduction requires _______ individual(s). 1; 1 2; 1 1; 2 2; 2
1; 2
When observing a bird skin cell in G2 under a microscope, you count 160 total chromatids. How many chromosomes does a male chicken have in its sperm cells? 40 320 80 160
40
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. Then goes peak B: it is wide but low. And then goes peak C, which 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 C only A, B, and C
A only
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. Then goes peak B: it is wide but low. And then goes peak C, which is narrow and low but higher than peak B. Which peak corresponds to cells in G1? In S phase? In G2? A: S; B: G1; C: G2 A: G2; B: S; C: G1 A: G1; B: G2; C: S A: G1; B: S; C: G2
A: G1; B: S; C: G2
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? 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. 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. Add cells from the tissue sample to a rat to see whether the rat develops cancer or not. Add cells from the tissue sample to a cell culture dish and compare their growth against a sample of noncancerous cells from the patient.
Add cells from the tissue sample to a cell culture dish and compare their growth against a sample of noncancerous cells from the patient.
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. Then goes peak B: it is wide but low. And then goes peak C, which 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
Which statement regarding cell division is false? Cell division is necessary for development to occur. Cell division is the basis of both sexual and asexual reproduction. Cell division can reproduce an entire organism. Cell division is common in eukaryotes but rare in prokaryotes
Cell division is common in eukaryotes but rare in prokaryotes
Which statement regarding the differences between mitosis and meiosis is false? In meiosis four daughter cells are produced, whereas in mitosis two daughter cells are produced. In mitosis cytokinesis occurs once, whereas in meiosis cytokinesis occurs twice. Crossing over is a phenomenon that creates genetic diversity during mitosis.
Crossing over is a phenomenon that creates genetic diversity during mitosis.
Which statement regarding Down syndrome is false? Down syndrome is the most common serious birth defect in the United States. People with Down syndrome usually have a shorter life span than normal. Trisomy 21 is the cause of Down syndrome. Down syndrome is least likely to be seen in the infants of mothers over 40
Down syndrome is least likely to be seen in the infants of mothers over 40
Part complete 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: G1; second view: metaphase; third view: cytokinesis First view: G1; second view: G2; third view: telophase First view: S; second view: prophase; third view: cytokinesis First view: G0; second view: G2; third view: telophase
First view: G1; second view: G2; third view: telophase
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. Then goes peak B: it is wide but low. And then goes peak C, which is narrow and low but higher than peak B. In this sample of cells, what stage of the cell cycle are most of the cells in? mitosis G2 S G1
G1
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? Haploid cells must undergo mitosis to produce a multicellular haploid stage. The haploid cells must undergo twice as much mitosis in order to produce a diploid stage. Haploid cells must undergo meiosis to form gametes. Meiosis must happen over and over to produce as many haploid cells for a multicellular haploid plant.
Haploid cells must undergo mitosis to produce a multicellular haploid stage.
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
Which statement correctly describes the behavior of a tetrad during anaphase I of meiosis? It splits into four chromosomes, which distribute in random pairs to the two poles of the dividing cell. It splits into two pairs of sister chromatids, and one pair goes to each pole of the dividing cell. It travels intact to one pole of the dividing cell. It splits into two pairs of homologous, nonsister chromatids, and one pair goes to each pole of the dividing cell.
It splits into two pairs of sister chromatids, and one pair goes to each pole of the dividing cell.
Which statement regarding the diploid life cycle is false? Two haploid cells fuse during fertilization. Meiosis of the zygote generates somatic cells. A zygote is a fertilized egg. Gametes are haploid cells.
Meiosis of the zygote generates somatic cells.
Which statement regarding mitosis and meiosis is false? In mitosis, the chromosomes replicate only once in the preceding interphase. Mitosis provides for growth and tissue repair. Meiosis provides for asexual reproduction. All the events unique to meiosis occur during meiosis I.
Meiosis provides for asexual reproduction.
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. Stage Sample 1 Sample 2 Interphase 74% 98% Prophase 18% 0.5% Metaphase 4% 0.2% Anaphase 2% 0.1% Telophase 1% 0.1% From the data shown what can you conclude about the amount of time these plant cells spend in various stages of the cell cycle? Metaphase lasts about twice as long as anaphase Cells spend more time in cytokinesis than in synthesizing new DNA during chromosomal duplication. Metaphase is the longest stage of mitosis. Cells spend less time in prophase than any other of the stages of mitosis.
Metaphase lasts about twice as long as anaphase
Which statement regarding mitosis and meiosis is false? Mitosis produces daughter cells with half the number of chromosomes as the parent cell. In animals, meiosis only occurs in the ovaries and testes. A normal human zygote has 46 chromosomes. All sexual life cycles involve an alternation of diploid and haploid stages.
Mitosis produces daughter cells with half the number of chromosomes as the parent cell.
Which statement regarding the function of mitosis is false? Mitosis promotes repair tissues. Mitosis promotes genetic diversity. Mitosis is necessary for asexual reproduction in eukaryotes. Mitosis allows organisms to grow.
Mitosis promotes genetic diversity.
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? Place a person's red blood cells in culture to see if they grow. Look at a person's skin cells in G1 under a light microscope. Count the number of chromosomes present. Perform a karyotype using a person's white blood cells.
Perform a karyotype using a person's white blood cells.
Which feature likely accounts for the difference between plant and animal cell cytokinesis? Animal cells lack chloroplasts. Plant cells have two sets of chromosomes; animal cells have one set of chromosomes. Animal cells lack the microfilaments required for forming a cleavage furrow. Plant cells have cell walls.
Plant cells have cell walls.
Which statement regarding prokaryotes is false? In prokaryotes, daughter chromosomes are separated by an active movement away from each other and the growth of a new plasma membrane between them. Most prokaryotes reproduce by binary fission. Prokaryotic chromosomes are more complex than those of eukaryotes. Prokaryotic cells are generally smaller and simpler than eukaryotic cells.
Prokaryotic chromosomes are more complex than those of eukaryotes.
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. Stage Sample 1 Sample 2 Interphase 74% 98% Prophase 18% 0.5% Metaphase 4% 0.2% Anaphase 2% 0.1% Telophase 1% 0.1% What can you conclude from these data? Sample 1 is likely from tissue in the middle of the plant because fewer cells are in any mitotic stage than in sample 2. Sample 2 is likely from tissue in the middle of the plant because there are fewer cells in telophase than are in prophase Sample 1 is likely from tissue in the middle of the plant because most cells are in interphase. Sample 2 is likely from tissue in the middle of the plant because fewer cells are in any mitotic stage.
Sample 2 is likely from tissue in the middle of the plant because fewer cells are in any mitotic stage.
Which statement regarding sexual and asexual reproduction is true? Only offspring from asexual reproduction inherit traits from two parents. Sexual reproduction is more likely to increase genetic variation than is asexual reproduction. Sexual reproduction typically includes the development of unfertilized eggs. Cell division only occurs after sexual reproduction.
Sexual reproduction is more likely to increase genetic variation than is asexual reproduction.
Which statement regarding mitosis and meiosis is true? Independent orientation occurs during metaphase of mitosis and metaphase II of meiosis. In metaphase of mitosis and metaphase I of meiosis, homologous chromosomes separate. Mitosis takes place in your gametes, whereas meiosis takes place in your somatic cells. Sister chromatids separate during anaphase of mitosis and anaphase II of meiosis.
Sister chromatids separate during anaphase of mitosis and anaphase II of meiosis.
Which statement regarding the cell cycle control system is false? The cell cycle control system receives messages from outside the cell that influence cell division. The cell cycle control system triggers and controls major events in the cell cycle. The cell cycle control system operates independently of the growth factors. The cell cycle control system includes three key checkpoints to
The cell cycle control system operates independently of the growth factors.
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 enter metaphase. The cell will enter prophase. The cell will divide into two plant cells. The cell will divide into two animal cells.
The cell will divide into two plant cells.
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 prevent them from adhering 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 result are you most likely to observe? The cells in flask A will have grown significantly, but the cells in flask B will have not grown at all. The cells in both flasks A and B will have grown significantly. The cells in both flasks A and B will have not grown at all. The cells in flask B will have grown significantly, but the cells in flask A will have not grown at all.
The cells in flask B will have grown significantly, but the cells in flask A will have not grown at all.
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 observation regarding the chromosomes would allow you to immediately conclude that the cell is a eukaryote? The chromosomes are very simple in structure. The chromosomes are circular in structure. The chromosomes contain very few proteins. The chromosomes are housed in a membrane-enclosed nucleus.
The chromosomes are housed in a membrane-enclosed nucleus.
What must occur for a plant or animal to grow and develop normally? Sufficient oxygen must be available to stimulate cell division. The organism must be able to control the timing and rate of cell division in different parts of its body. Sufficient light must be available to stimulate cell division. The organism must receive a supply of the appropriate hormones from its parents.
The organism must be able to control the timing and rate of cell division in different parts of its body.
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? The single cell divided once to form four new cells via asexual reproduction. 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. 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. The single cell divided once to form four new cells via sexual reproduction.
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.
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 Down syndrome Turner syndrome Klinefelter syndrome
Turner syndrome
In comparing a frog cell in metaphase of mitosis with one in metaphase I of meiosis, how would tell you which was which? In mitosis, the chromosomes would be unduplicated (single-stranded) and in meiosis, they would be double-stranded (made up of sister chromatids). Unlike mitosis, in meiosis each chromosome would be opposite its homolog. In meiosis, the chromosomes would be unduplicated (single-stranded) and in mitosis, they would be double-stranded (made up of sister chromatids). Unlike meiosis, in mitosis each chromosome would be paired with its homolog.
Unlike mitosis, in meiosis each chromosome would be opposite its homolog.
Which variation of the sentence "Where is the cat?" is most like a chromosomal inversion? Where is cat? Where the is cat? Where is cat the the cat? Where is the the cat?
Where the is cat?
Maternal age and incidence of Down syndrome. Source: Adapted from C. A. Huether et al., Maternal age specific risk rate estimates for Down syndrome among live births in whites and other races from Ohio and Metropolitan Atlanta, 1970-1989, Journal of Medical Genetics 35: 482-90 (1998). Which conclusion can best be drawn from this study? Women of age 20 or younger never have a child with Down syndrome. Many babies with Down syndrome die before birth. Women in this study who were 45 years old had three times the incidence of babies with Down syndrome as did 40-year-old women. For 40-year-old women around the world, ten births per thousand have Down syndrome.
Women in this study who were 45 years old had three times the incidence of babies with Down syndrome as did 40-year-old women.
A pair of sex chromosomes found in a human male is most like a bride and groom. a knife, fork, and spoon. a pair of blue jeans. identical twins.
a bride and groom.
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 sperm-producing tissue of the testis. a cancerous tumor. liver from a cow. skin from a human.
a cancerous tumor.
Which drug shows the greatest promise as a cancer chemotherapy agent? a drug that prevents tetrad formation a drug that prevents mitotic spindle from forming a drug that prevents crossing over a drug that interferes with organismal cellular respiration
a drug that prevents mitotic spindle from forming
Part complete With the exception of identical twins, siblings who have the same two biological parents are likely to look similar, but not identical, to each other because they have identical genes but different chromosomes. identical chromosomes but different genes. the same combination of traits but different genes. a similar but not identical combination of genes.
a similar but not identical combination of genes.
Use the figure below to answer the question that follows. The age of a mother versus the chance of infants with down syndrome per 1,000 births. It demonstrates how the older a mother is, the more likely they are to have a child with down syndrome. Age of mother, Infants with Down Syndrome, per 1,000 births20, 125, 130, 235, 340, 945, 3150, 80 Source: Adapted from C. A. Huether et al., Maternal age specific risk rate estimates for Down syndrome among live births in whites and other races from Ohio and Metropolitan Atlanta, 1970-1989, Journal of Medical Genetics 35: 482-90 (1998). Figure 8.20B Maternal age and incidence of Down syndrome According to the graph, at what maternal age is the incidence of Down syndrome equal to five times the incidence at age 40? about 35 or 36 about 44 or 45 about 29 or 30 about 46 or 47
about 44 or 45
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 II anaphase II telophase I prophase I
anaphase II
Eukaryotic chromosomes differ from prokaryotic chromosomes in that they are housed in a membrane-enclosed nucleus. are circular in structure. include fewer proteins. are simpler.
are housed in a membrane-enclosed nucleus.
Mature human neuron (nerve) cells and muscle cells become cancerous more easily than other cell types. continue to divide throughout their lifetime. are permanently in a state of nondivision. cease dividing after a predetermined number of cell generations.
are permanently in a state of nondivision.
The creation of genetically identical offspring by a single parent, without the participation of sperm and egg, is called asexual reproduction. sexual reproduction. regeneration. spontaneous generation.
asexual reproduction
Strictly speaking, the phrase "like begets like" refers to all forms of reproduction. sexual reproduction only. asexual reproduction only.
asexual reproduction only.
Karyotyping examines points of crossing over. can reveal alterations in chromosome number. shows chromosomes as they appear in metaphase of meiosis II. reveals the presence of cancerous genes.
can reveal alterations in chromosome number.
Which event occurs during interphase? cytokinesis cell growth and duplication of the chromosomes a reduction in the size of the nuclear membrane separation of newly formed DNA to opposite ends of the cell
cell growth and duplication of the chromosomes
The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called binary fission. telophase. cytokinesis. mitosis
cytokinesis.
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 density-independent inhibition. density-dependent inhibition. growth factor inhibition. anchorage independence.
density-dependent inhibition.
When animal cells are grown in a petri dish, they typically stop dividing once they have formed a single, unbroken layer on the bottom of the dish. This arrest of division is an example of lack of nutrients. mitosis S phase. density-dependent inhibition.
density-dependent inhibition.
A benign tumor differs from a malignant tumor in that a benign tumor is cancerous. spreads from the original site. does not metastasize. never causes health problems.
does not metastasize.
You see a cell with several nuclei and you know that something is different about cell division. What is the most likely explanation? failure of sister chromatids to separate failure of homologous chromosomes to separate failure of cytokinesis following mitosis nondisjunction
failure of cytokinesis following mitosis
Which type of organisms commonly demonstrates polyploidy? reptiles fish flowering plants mammals
flowering plants
Which feature of plant cell division distinguishes it from animal cell division? production of four (rather than two) new cells per mitotic division formation of a cleavage furrow formation of a cell plate lack of cytokinesis
formation of a cell plate
Two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are complementary chromosomes. sister chromatids. homologous chromosomes.
homologous chromosomes.
At a chiasma, two ________ are attached to each other. daughter cells nonhomologous chromosomes homologous or nonsister chromatids homologous or sister chromatids
homologous or nonsister chromatids
Eukaryotic cells spend most of their cell cycle in which phase? interphase telophase prophase metaphase
interphase
Both mitosis and meiosis are preceded by interphase. prophase. prometaphase. telophase.
interphase.
If a chromosome fragment breaks off and then reattaches to the original chromosome but in the reverse direction, the resulting chromosomal abnormality is called a(n) reciprocal translocation. deletion. translocation. inversion.
inversion
Sister chromatids are made only of DNA. joined together at a centromere. unique to prokaryotes. found immediately after a cell divides.
joined together at a centromere.
What is the stage of cell division in a diploid organism if you see seven chromosomes, each consisting of a pair of sister chromatids? mitosis anaphase meiosis II prophase mitosis prophase meiosis I anaphase
meiosis II prophase
Nondisjunction occurs when a portion of a chromosome breaks off and is lost. an entire pair of chromosomes is lost during meiosis I. members of a chromosome pair fail to separate. two chromosomes fuse into one.
members of a chromosome pair fail to separate.
During which phase of mitosis do the chromosomes line up on a plane equidistant from the two spindle poles? metaphase telophase anaphase prophase
metaphase
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 intestinal cells. muscle or nerve cells. bone cells. skin cells.
muscle or nerve cells.
If the four cells shown resulted from cell division of a single cell with diploid chromosome number 2n = 4, what best describes what just occurred? The figure shows four gametes, two with n number of chromosomes, one with n plus 1 chromosome, and one with n minus 1 chromosome. translocation nondisjunction inversion normal meiosis
nondisjunction
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 nondisjunction involving a Y chromosome. an inversion of the X chromosome, preventing the pairing of sex chromosomes. failure of the second meiotic division to take place. formation of diploid sperm.
nondisjunction involving a Y chromosome.
A karyotype is most like the answer key to a multiple-choice exam. a movie showing the stages of the reproductive cycle of a beetle. photographs of every couple at a high school prom. a map showing the hidden location of buried treasure
photographs of every couple at a high school prom.
What is probably the main factor responsible for the phenomenon of density-dependent inhibition? physical contact of cell-surface proteins between adjacent cells a local deficiency of nutrients a local accumulation of growth-inhibiting factors cells' innate ability to "sense" when the organ of which they are a part has no need for additional cells
physical contact of cell-surface proteins between adjacent cells
Part complete A cell that has a cell wall is undergoing cell division, and the following events are observed: the formation of a cell plate and the division of the cell into two daughter cells. What type of cell is being observed and what process(es) is it going through? animal cell; telophase and cytokinesis of mitosis prokaryote; telophase of mitosis plant cell; telophase and cytokinesis of mitosis plant cell; telophase II of meiosis
plant cell; telophase and cytokinesis of mitosis
Independent orientation of chromosomes at metaphase I results in an increase in the number of homologous chromosomes. sex chromosomes. gametes. possible combinations of characteristics.
possible combinations of characteristics.
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? metaphase prophase anaphase telophase
prophase
The phase of mitosis during which the mitotic spindle begins to form is metaphase. interphase. prophase. anaphase.
prophase.
What helps maintain the structure of chromosomes and control the activity of genes? proteins centromeres ribosomes the nuclear membrane
proteins
Prior to mitosis and after S phase, each chromosome of a eukaryotic cell consists of a pair of identical structures called nucleoli. sister chromatids. chromatin. sister chromosomes.
sister chromatids.
Part complete 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) six 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)
Part complete During which phase of mitosis does the nuclear envelope re-form? metaphase prophase telophase anaphase
telophase
The genetic material is duplicated during G2. G1. the mitotic phase. the S phase.
the S phase.
At the start of mitotic anaphase, the centromeres of each chromosome come apart. nuclear envelopes begin to form around the chromosomes. equivalent and complete collections of chromosomes have reached the two poles. the chromatid DNA replicates.
the centromeres of each chromosome come apart.
Cancer is not usually inherited because the chromosomal changes in cancer are usually confined to somatic cells. people with cancer usually die before reproducing. the causes of cancer are not usually genetic. the cancerous cells usually interfere with the ability to produce gametes.
the chromosomal changes in cancer are usually confined to somatic cells.
Cancer is caused by sexual reproduction. uncontrolled cell division. rapid binary fission. formation of eggs and sperm.
uncontrolled cell division.
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. about to undergo mitosis. undergoing cytokinesis. in the S phase of interphase.
undergoing cytokinesis.