Mitosis and Meiosis - MCAT Biology
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During metaphase, the chromosomes of the cell are __________.
During metaphase, the chromosomes of the cell are __________.
During metaphase, chromosomes align along the metaphase plate, in preparation for anaphase. This phase of the cell cycle is highly visible as a distinct band of chromosomes lined up in the center of the cell.
During metaphase, chromosomes align along the metaphase plate, in preparation for anaphase. This phase of the cell cycle is highly visible as a distinct band of chromosomes lined up in the center of the cell.
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Which stage of mitosis is shown in the illustration?
Which stage of mitosis is shown in the illustration?
This cell is in metaphase. This can be determined because the chromosomes are lined up on in the middle. This is known as the metaphase plate. After alignment the microtubules attach, and the chromosomes are ready to be seperated, which is the next phase (anaphase).
This cell is in metaphase. This can be determined because the chromosomes are lined up on in the middle. This is known as the metaphase plate. After alignment the microtubules attach, and the chromosomes are ready to be seperated, which is the next phase (anaphase).
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Something goes wrong during meiosis in a male and the four daughter sperm cells that are produced all have the wrong amount of chromosomes. Two of the sperm have one extra chromosome and the other two have one missing chromosome. At what step did the problem most likely occur, and what was it?
Something goes wrong during meiosis in a male and the four daughter sperm cells that are produced all have the wrong amount of chromosomes. Two of the sperm have one extra chromosome and the other two have one missing chromosome. At what step did the problem most likely occur, and what was it?
If nondisjunction occurs in Metaphase I, then one extra chromosome composed of two tetrads would go into one of the cells starting metaphase II while the other would have one less. This extra chromosome would then undergo the rest of meiosis normally, leaving an extra chromosome, composed of one tetrad in two of the daughter sperm. These are the two that are missing from the other daughter sperm.
If nondisjunction occurs in Metaphase I, then one extra chromosome composed of two tetrads would go into one of the cells starting metaphase II while the other would have one less. This extra chromosome would then undergo the rest of meiosis normally, leaving an extra chromosome, composed of one tetrad in two of the daughter sperm. These are the two that are missing from the other daughter sperm.
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Which answer choice incorrectly matches the type of chromatin with the phase of mitosis?
Which answer choice incorrectly matches the type of chromatin with the phase of mitosis?
DNA is stored in loosely wound euchromatin before mitosis. During mitosis, the DNA condenses into chromosomes, which are made of heterochromatin. It becomes more dense during prophase, and stays that way until the end of mitosis. Euchromatin is more lightly packed than heterochromatin.
Mitosis follows the following sequence: prophase, metaphase, anaphase, telophase, cytokinesis. Interphase refers to the time period between mitotic divisions. During interphase, most DNA is euchromatin, but some regions remain as heterochromatin to prevent unwanted transcription; thus DNA exists as both types of chromatin during interphase, but only as heterochromatin during mitosis. Matching euchromatin to telophase is the answer, as this is a false statement.
DNA is stored in loosely wound euchromatin before mitosis. During mitosis, the DNA condenses into chromosomes, which are made of heterochromatin. It becomes more dense during prophase, and stays that way until the end of mitosis. Euchromatin is more lightly packed than heterochromatin.
Mitosis follows the following sequence: prophase, metaphase, anaphase, telophase, cytokinesis. Interphase refers to the time period between mitotic divisions. During interphase, most DNA is euchromatin, but some regions remain as heterochromatin to prevent unwanted transcription; thus DNA exists as both types of chromatin during interphase, but only as heterochromatin during mitosis. Matching euchromatin to telophase is the answer, as this is a false statement.
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Human chromosomes are divided into two arms, a long q arm and a short p arm. A karyotype is the organization of a human cell’s total genetic complement. A typical karyotype is generated by ordering chromosome 1 to chromosome 23 in order of decreasing size.
When viewing a karyotype, it can often become apparent that changes in chromosome number, arrangement, or structure are present. Among the most common genetic changes are Robertsonian translocations, involving transposition of chromosomal material between long arms of certain chromosomes to form one derivative chromosome. Chromosomes 14 and 21, for example, often undergo a Robertsonian translocation, as below.
A karyotype of this individual for chromosomes 14 and 21 would thus appear as follows:
Though an individual with aberrations such as a Robertsonian translocation may be phenotypically normal, they can generate gametes through meiosis that have atypical organizations of chromosomes, resulting in recurrent fetal abnormalities or miscarriages.
Chromosomes are important participants in both meiosis and mitosis. Which of the following is false of meiosis?
Human chromosomes are divided into two arms, a long q arm and a short p arm. A karyotype is the organization of a human cell’s total genetic complement. A typical karyotype is generated by ordering chromosome 1 to chromosome 23 in order of decreasing size.
When viewing a karyotype, it can often become apparent that changes in chromosome number, arrangement, or structure are present. Among the most common genetic changes are Robertsonian translocations, involving transposition of chromosomal material between long arms of certain chromosomes to form one derivative chromosome. Chromosomes 14 and 21, for example, often undergo a Robertsonian translocation, as below.
A karyotype of this individual for chromosomes 14 and 21 would thus appear as follows:
Though an individual with aberrations such as a Robertsonian translocation may be phenotypically normal, they can generate gametes through meiosis that have atypical organizations of chromosomes, resulting in recurrent fetal abnormalities or miscarriages.
Chromosomes are important participants in both meiosis and mitosis. Which of the following is false of meiosis?
This is a tricky question because all of the choices are correct, except for one minor part. Meiosis sees cells undergo a reduction division in the first division. That means that after the first meiotic division, the diploid germ cell has become a haploid.
This is a tricky question because all of the choices are correct, except for one minor part. Meiosis sees cells undergo a reduction division in the first division. That means that after the first meiotic division, the diploid germ cell has become a haploid.
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Scientists use a process called Flourescent In-Situ Hybridization, or FISH, to study genetic disorders in humans. FISH is a technique that uses spectrographic analysis to determine the presence or absence, as well as the relative abundance, of genetic material in human cells.
To use FISH, scientists apply fluorescently-labeled bits of DNA of a known color, called probes, to samples of test DNA. These probes anneal to the sample DNA, and scientists can read the colors that result using laboratory equipment. One common use of FISH is to determine the presence of extra DNA in conditions of aneuploidy, a state in which a human cell has an abnormal number of chromosomes. Chromosomes are collections of DNA, the totality of which makes up a cell’s genome. Another typical use is in the study of cancer cells, where scientists use FISH labels to ascertain if genes have moved inappropriately in a cell’s genome.
Using red fluorescent tags, scientists label probe DNA for a gene known to be expressed more heavily in cancer cells than normal cells. They then label a probe for an immediately adjacent DNA sequence with a green fluorescent tag. Both probes are then added to three dishes, shown below. In dish 1 human bladder cells are incubated with the probes, in dish 2 human epithelial cells are incubated, and in dish 3 known non-cancerous cells are used. The relative luminescence observed in regions of interest in all dishes is shown below.
In cancer cells, karyotype analysis shows the specific arrangement of chromosomes. Often, as cancer cells divide uncontrollably, the number of chromosomes becomes deranged. In which of the following stages of mitosis is a non-disjunction most likely to occur?
Scientists use a process called Flourescent In-Situ Hybridization, or FISH, to study genetic disorders in humans. FISH is a technique that uses spectrographic analysis to determine the presence or absence, as well as the relative abundance, of genetic material in human cells.
To use FISH, scientists apply fluorescently-labeled bits of DNA of a known color, called probes, to samples of test DNA. These probes anneal to the sample DNA, and scientists can read the colors that result using laboratory equipment. One common use of FISH is to determine the presence of extra DNA in conditions of aneuploidy, a state in which a human cell has an abnormal number of chromosomes. Chromosomes are collections of DNA, the totality of which makes up a cell’s genome. Another typical use is in the study of cancer cells, where scientists use FISH labels to ascertain if genes have moved inappropriately in a cell’s genome.
Using red fluorescent tags, scientists label probe DNA for a gene known to be expressed more heavily in cancer cells than normal cells. They then label a probe for an immediately adjacent DNA sequence with a green fluorescent tag. Both probes are then added to three dishes, shown below. In dish 1 human bladder cells are incubated with the probes, in dish 2 human epithelial cells are incubated, and in dish 3 known non-cancerous cells are used. The relative luminescence observed in regions of interest in all dishes is shown below.
In cancer cells, karyotype analysis shows the specific arrangement of chromosomes. Often, as cancer cells divide uncontrollably, the number of chromosomes becomes deranged. In which of the following stages of mitosis is a non-disjunction most likely to occur?
During anaphase two chromosomes over the metaphase plate are separated, and each daughter cell gets one copy. If this happens inappropriately and separation does not occur, a nondisjunction takes place.
During anaphase two chromosomes over the metaphase plate are separated, and each daughter cell gets one copy. If this happens inappropriately and separation does not occur, a nondisjunction takes place.
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Combrestatin is a drug that prevents the polymerization of microtubules. Which of the following processes would be most affected by combrestatin?
Combrestatin is a drug that prevents the polymerization of microtubules. Which of the following processes would be most affected by combrestatin?
Combrestatin interferes with the formation of microtubules, which make up the cytoskeletal architecture of a cell; therefore, the correct answer choice is involved with some microtubule-based process. DNA and protein synthesis do not involve microtubules, and would not be affected by the lack thereof. Muscle contraction depends on myosin, actin, troponin, etc., and not on microtubules. Membrane depolarization involves sodium/potassium channels, neurotransmitters, etc., and is not directly affected by microtubule inhibition.
The only answer that remains is mitosis, which involves microtubules in chromosomal segregation. The mitotic spindle in this separation is primarily composed of microtubules. The polymerization and depolymerization of microtubules is crucial for mitotic division. Combrestatin therefore prevents proper mitosis.
Combrestatin interferes with the formation of microtubules, which make up the cytoskeletal architecture of a cell; therefore, the correct answer choice is involved with some microtubule-based process. DNA and protein synthesis do not involve microtubules, and would not be affected by the lack thereof. Muscle contraction depends on myosin, actin, troponin, etc., and not on microtubules. Membrane depolarization involves sodium/potassium channels, neurotransmitters, etc., and is not directly affected by microtubule inhibition.
The only answer that remains is mitosis, which involves microtubules in chromosomal segregation. The mitotic spindle in this separation is primarily composed of microtubules. The polymerization and depolymerization of microtubules is crucial for mitotic division. Combrestatin therefore prevents proper mitosis.
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When does genetic crossover occur during meiosis?
When does genetic crossover occur during meiosis?
This is a simple memorization problem. Crossover occurs when the nucleus decondenses. The chromosomes are able to crossover during prophase I when chromosome pairs are aligned next to one another. Crossover cannot occur later in meiosis, as the chromosomes have already been separated.
This is a simple memorization problem. Crossover occurs when the nucleus decondenses. The chromosomes are able to crossover during prophase I when chromosome pairs are aligned next to one another. Crossover cannot occur later in meiosis, as the chromosomes have already been separated.
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Which of the following lists the correct sequence of mitotic events?
Which of the following lists the correct sequence of mitotic events?
The mitotic sequence occurs during the M phase of the cell cycle. The process is outlined below.
Prophase—chromosomes condense
Metaphase—chromosomes align in the center of the cell
Anaphase—sister chromatids begin to separate
Telophase—separated chromosomes decondense (relax)
Cytokinesis—the cytosol of the cell completely separates and the membranes fuse shut
The mitotic sequence occurs during the M phase of the cell cycle. The process is outlined below.
Prophase—chromosomes condense
Metaphase—chromosomes align in the center of the cell
Anaphase—sister chromatids begin to separate
Telophase—separated chromosomes decondense (relax)
Cytokinesis—the cytosol of the cell completely separates and the membranes fuse shut
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During which mitotic stage do the spindle fibers begin to form from microtubules?
During which mitotic stage do the spindle fibers begin to form from microtubules?
The fibers of the spindle apparatus function by attaching to the centromeres of chromosomes and shortening, pulling the chromosomes to opposite ends of the cell. Since chromosomes line up on the apparatus during metaphase, we know that the spindle apparatus must have begun to form during prophase. The spindle attach during metaphase, and pull the chromatids apart during anaphase.
The fibers of the spindle apparatus function by attaching to the centromeres of chromosomes and shortening, pulling the chromosomes to opposite ends of the cell. Since chromosomes line up on the apparatus during metaphase, we know that the spindle apparatus must have begun to form during prophase. The spindle attach during metaphase, and pull the chromatids apart during anaphase.
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A mouse has a mutation in which its sister chromatids are unable to separate during cell division. What phase of mitosis should researchers target, in order to alleviate the condition using drug therapy?
A mouse has a mutation in which its sister chromatids are unable to separate during cell division. What phase of mitosis should researchers target, in order to alleviate the condition using drug therapy?
During anaphase, sister chromatids are separated and pulled to polar ends of the cell. Drug therapy would best be able to target the mutation during this phase of mitosis.
Chromosomes condense and exit the nucleus during prophase. Alignment along the equatorial plate occurs during metaphase. Separation occurs during anaphase, and the nuclei begin to re-form during telophase in preparation for cytokinesis.
During anaphase, sister chromatids are separated and pulled to polar ends of the cell. Drug therapy would best be able to target the mutation during this phase of mitosis.
Chromosomes condense and exit the nucleus during prophase. Alignment along the equatorial plate occurs during metaphase. Separation occurs during anaphase, and the nuclei begin to re-form during telophase in preparation for cytokinesis.
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The concept of genomic imprinting is important in human genetics. In genomic imprinting, a certain region of DNA is only expressed by one of the two chromosomes that make up a typical homologous pair. In healthy individuals, genomic imprinting results in the silencing of genes in a certain section of the maternal chromosome 15. The DNA in this part of the chromosome is "turned off" by the addition of methyl groups to the DNA molecule. Healthy people will thus only have expression of this section of chromosome 15 from paternally-derived DNA.
The two classic human diseases that illustrate defects in genomic imprinting are Prader-Willi and Angelman Syndromes. In Prader-Willi Syndrome, the section of paternal chromosome 15 that is usually expressed is disrupted, such as by a chromosomal deletion. In Angelman Syndrome, maternal genes in this section are deleted, while paternal genes are silenced. Prader-Willi Syndrome is thus closely linked to paternal inheritance, while Angelman Syndrome is linked to maternal inheritance.
Figure 1 shows the chromosome 15 homologous pair for a child with Prader-Willi Syndrome. The parental chromosomes are also shown. The genes on the mother’s chromosomes are silenced normally, as represented by the black boxes. At once, there is also a chromosomal deletion on one of the paternal chromosomes. The result is that the child does not have any genes expressed that are normally found on that region of this chromosome.
A scientist is investigating a cell undergoing division, and notes that chromosome 15 is aligned with the other chromosomes in the center of the cell, as if along a line. Each of the 23 pairs of chromosomes is arranged as a tetrad along this plate. Which phase of cell division is this cell most likely undergoing?
The concept of genomic imprinting is important in human genetics. In genomic imprinting, a certain region of DNA is only expressed by one of the two chromosomes that make up a typical homologous pair. In healthy individuals, genomic imprinting results in the silencing of genes in a certain section of the maternal chromosome 15. The DNA in this part of the chromosome is "turned off" by the addition of methyl groups to the DNA molecule. Healthy people will thus only have expression of this section of chromosome 15 from paternally-derived DNA.
The two classic human diseases that illustrate defects in genomic imprinting are Prader-Willi and Angelman Syndromes. In Prader-Willi Syndrome, the section of paternal chromosome 15 that is usually expressed is disrupted, such as by a chromosomal deletion. In Angelman Syndrome, maternal genes in this section are deleted, while paternal genes are silenced. Prader-Willi Syndrome is thus closely linked to paternal inheritance, while Angelman Syndrome is linked to maternal inheritance.
Figure 1 shows the chromosome 15 homologous pair for a child with Prader-Willi Syndrome. The parental chromosomes are also shown. The genes on the mother’s chromosomes are silenced normally, as represented by the black boxes. At once, there is also a chromosomal deletion on one of the paternal chromosomes. The result is that the child does not have any genes expressed that are normally found on that region of this chromosome.
A scientist is investigating a cell undergoing division, and notes that chromosome 15 is aligned with the other chromosomes in the center of the cell, as if along a line. Each of the 23 pairs of chromosomes is arranged as a tetrad along this plate. Which phase of cell division is this cell most likely undergoing?
Metaphase I is the best answer. Because the chromosomes are arranged as tetrads, we know that it is in meiosis I. Only in meiosis I do we separate homologous chromosome pairs, rather than sister chromatids.
Additionally, because the chromosomes are aligned in the center of the cell, metaphase is the most likely phase of meiosis. Anaphase involves the separation of chromosomes, and telophase is the terminal phase after full separation is accomplished.
Metaphase I is the best answer. Because the chromosomes are arranged as tetrads, we know that it is in meiosis I. Only in meiosis I do we separate homologous chromosome pairs, rather than sister chromatids.
Additionally, because the chromosomes are aligned in the center of the cell, metaphase is the most likely phase of meiosis. Anaphase involves the separation of chromosomes, and telophase is the terminal phase after full separation is accomplished.
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Cellular division is an essential part of the cell cycle. When a cell divides it passes genetic information to daughter cells. The amount of genetic information passed on to daughter cells depends on whether the cell undergoes mitosis or meiosis. Mitosis is the most common form of cell division. All somatic cells undergo mitosis, whereas only germ cells undergo meiosis. Meiosis is very important because it produces gametes (sperm and eggs) that are required for sexual reproduction. Human germ cells have 46 chromosomes (2n = 46) and undergo meiosis to produce four haploid daughter cells (gametes).
Which of the following would occur in humans if meiosis produced diploid gametes?
Cellular division is an essential part of the cell cycle. When a cell divides it passes genetic information to daughter cells. The amount of genetic information passed on to daughter cells depends on whether the cell undergoes mitosis or meiosis. Mitosis is the most common form of cell division. All somatic cells undergo mitosis, whereas only germ cells undergo meiosis. Meiosis is very important because it produces gametes (sperm and eggs) that are required for sexual reproduction. Human germ cells have 46 chromosomes (2n = 46) and undergo meiosis to produce four haploid daughter cells (gametes).
Which of the following would occur in humans if meiosis produced diploid gametes?
Meiosis is the process by which haploid gametes are produced. The attachment of a haploid sperm to a haploid egg begins the process of development and fertilization. In humans a sperm containing 23 chromosomes joins with an egg containing 23 chromosomes to create an organism with 46 chromosomes.
If meiosis were to produce diploid gametes, then the diploid gametes would combine to form an organism that contains twice as many chromosomes as the parent. For example, a diploid sperm and egg (containing 46 chromosomes each) would create an organism with 92 chromosomes. This new organism would produce another organism with 184 chromosomes (double 92). The subsequent generations would have twice as many chromosomes as the previous generation, and the amount of chromosomes would increase exponentially.
Offspring 1: 92 chromosomes
Offspring 2: 184 chromosomes
Offspring 3: 368 chromosomes
The best answer is that the number of chromosomes in subsequent generations would increase exponentially.
Meiosis is the process by which haploid gametes are produced. The attachment of a haploid sperm to a haploid egg begins the process of development and fertilization. In humans a sperm containing 23 chromosomes joins with an egg containing 23 chromosomes to create an organism with 46 chromosomes.
If meiosis were to produce diploid gametes, then the diploid gametes would combine to form an organism that contains twice as many chromosomes as the parent. For example, a diploid sperm and egg (containing 46 chromosomes each) would create an organism with 92 chromosomes. This new organism would produce another organism with 184 chromosomes (double 92). The subsequent generations would have twice as many chromosomes as the previous generation, and the amount of chromosomes would increase exponentially.
Offspring 1: 92 chromosomes
Offspring 2: 184 chromosomes
Offspring 3: 368 chromosomes
The best answer is that the number of chromosomes in subsequent generations would increase exponentially.
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Cellular division is an essential part of the cell cycle. When a cell divides it passes genetic information to daughter cells. The amount of genetic information passed on to daughter cells depends on whether the cell undergoes mitosis or meiosis. Mitosis is the most common form of cell division. All somatic cells undergo mitosis, whereas only germ cells undergo meiosis. Meiosis is very important because it produces gametes (sperm and eggs) that are required for sexual reproduction. Human germ cells have 46 chromosomes (2n = 46) and undergo meiosis to produce four haploid daughter cells (gametes).
Meiosis is a form of __________ reproduction and mitosis is a form of __________ reproduction.
Cellular division is an essential part of the cell cycle. When a cell divides it passes genetic information to daughter cells. The amount of genetic information passed on to daughter cells depends on whether the cell undergoes mitosis or meiosis. Mitosis is the most common form of cell division. All somatic cells undergo mitosis, whereas only germ cells undergo meiosis. Meiosis is very important because it produces gametes (sperm and eggs) that are required for sexual reproduction. Human germ cells have 46 chromosomes (2n = 46) and undergo meiosis to produce four haploid daughter cells (gametes).
Meiosis is a form of __________ reproduction and mitosis is a form of __________ reproduction.
The key difference between sexual and asexual reproduction is recombination. If a process involves shuffling of genetic material between chromosomes (recombination), then it is sexual reproduction. Recall that crossing over, a type of genetic recombination, occurs during prophase I of meiosis. This leads to the production of daughter cells that are distinct from the parents; therefore, meiosis is a form of sexual reproduction.
In mitosis there is no genetic recombination and the daughter cells are identical to the parent cells; therefore, mitosis is a form of asexual reproduction.
The key difference between sexual and asexual reproduction is recombination. If a process involves shuffling of genetic material between chromosomes (recombination), then it is sexual reproduction. Recall that crossing over, a type of genetic recombination, occurs during prophase I of meiosis. This leads to the production of daughter cells that are distinct from the parents; therefore, meiosis is a form of sexual reproduction.
In mitosis there is no genetic recombination and the daughter cells are identical to the parent cells; therefore, mitosis is a form of asexual reproduction.
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Cellular division is an essential part of the cell cycle. When a cell divides it passes genetic information to daughter cells. The amount of genetic information passed on to daughter cells depends on whether the cell undergoes mitosis or meiosis. Mitosis is the most common form of cell division. All somatic cells undergo mitosis, whereas only germ cells undergo meiosis. Meiosis is very important because it produces gametes (sperm and eggs) that are required for sexual reproduction. Human germ cells have 46 chromosomes (2n = 46) and undergo meiosis to produce four haploid daughter cells (gametes).
Which of the following is true regarding mitosis and meiosis?
I. Meiosis I produces twice as many daughter cells as mitosis
II. Crossing over only occurs during prophase I of meiosis
III. The daughter cells of meiosis I have the same amount of DNA as the daughter cells of mitosis
Cellular division is an essential part of the cell cycle. When a cell divides it passes genetic information to daughter cells. The amount of genetic information passed on to daughter cells depends on whether the cell undergoes mitosis or meiosis. Mitosis is the most common form of cell division. All somatic cells undergo mitosis, whereas only germ cells undergo meiosis. Meiosis is very important because it produces gametes (sperm and eggs) that are required for sexual reproduction. Human germ cells have 46 chromosomes (2n = 46) and undergo meiosis to produce four haploid daughter cells (gametes).
Which of the following is true regarding mitosis and meiosis?
I. Meiosis I produces twice as many daughter cells as mitosis
II. Crossing over only occurs during prophase I of meiosis
III. The daughter cells of meiosis I have the same amount of DNA as the daughter cells of mitosis
Meiosis contains two different cellular divisions: meiosis I and meiosis II. Meiosis I produces two haploid daughter cells with chromosomes composed of two sister chromatids, whereas meiosis II produces four haploid daughter cells with singular sister chromatids (single-chromatid chromosomes). Mitosis only has one cellular division and produces two diploid daughter cells.
Statement I is false because meiosis I and mitosis produce the same number of daughter cells. Both divisions result in two daughter cells. Meiosis II divisions will result in four daughter cells.
Crossing over is a type of genetic recombination that exclusively occurs during prophase I of meiosis; therefore, statement II is true. This occurs because crossing over requires the formation of tetrads of homologous chromosomes.
The daughter cells of mitosis contain one sister chromatid from each homologous chromosome and the daughter cells of meiosis I contain one homologous chromosome from each pair. Although their types of chromosomes are different, both daughter cells from each division contain the same amount of DNA. The only difference is that the daughter cells of mitosis contain DNA in the form of sister chromatids, whereas daughter cells of meiosis I contain DNA in the form of the homologous chromosome. Statement III is true. The best answer is II and III. Remember that sister chromatids and homologous chromosomes code for the same genes, but contain different alleles.
Meiosis contains two different cellular divisions: meiosis I and meiosis II. Meiosis I produces two haploid daughter cells with chromosomes composed of two sister chromatids, whereas meiosis II produces four haploid daughter cells with singular sister chromatids (single-chromatid chromosomes). Mitosis only has one cellular division and produces two diploid daughter cells.
Statement I is false because meiosis I and mitosis produce the same number of daughter cells. Both divisions result in two daughter cells. Meiosis II divisions will result in four daughter cells.
Crossing over is a type of genetic recombination that exclusively occurs during prophase I of meiosis; therefore, statement II is true. This occurs because crossing over requires the formation of tetrads of homologous chromosomes.
The daughter cells of mitosis contain one sister chromatid from each homologous chromosome and the daughter cells of meiosis I contain one homologous chromosome from each pair. Although their types of chromosomes are different, both daughter cells from each division contain the same amount of DNA. The only difference is that the daughter cells of mitosis contain DNA in the form of sister chromatids, whereas daughter cells of meiosis I contain DNA in the form of the homologous chromosome. Statement III is true. The best answer is II and III. Remember that sister chromatids and homologous chromosomes code for the same genes, but contain different alleles.
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Cellular division is an essential part of the cell cycle. When a cell divides it passes genetic information to daughter cells. The amount of genetic information passed on to daughter cells depends on whether the cell undergoes mitosis or meiosis. Mitosis is the most common form of cell division. All somatic cells undergo mitosis, whereas only germ cells undergo meiosis. Meiosis is very important because it produces gametes (sperm and eggs) that are required for sexual reproduction. Human germ cells have 46 chromosomes (2n = 46) and undergo meiosis to produce four haploid daughter cells (gametes).
Which of the following is not a characteristic of meiosis?
Cellular division is an essential part of the cell cycle. When a cell divides it passes genetic information to daughter cells. The amount of genetic information passed on to daughter cells depends on whether the cell undergoes mitosis or meiosis. Mitosis is the most common form of cell division. All somatic cells undergo mitosis, whereas only germ cells undergo meiosis. Meiosis is very important because it produces gametes (sperm and eggs) that are required for sexual reproduction. Human germ cells have 46 chromosomes (2n = 46) and undergo meiosis to produce four haploid daughter cells (gametes).
Which of the following is not a characteristic of meiosis?
Meiosis is the process by which a diploid cell divides into four haploid daughter cells. The daughter cells produced are called gametes (sperm in males and egg in females). By definition, a haploid cell contains only one set of chromosomes; therefore, the egg and sperm cells will not contain any homologous chromosomes.
Recall that mitosis is part of the cell cycle and that it is preceded by three phases: G1 phase, S phase, and G2 phase. Meiosis is immediately followed by the G2 phase. The main function of meiosis is to produce haploid gametes that can be used for sexual reproduction. Growth and repair of tissues in the human body is accomplished by mitosis, not meiosis.
Meiosis is the process by which a diploid cell divides into four haploid daughter cells. The daughter cells produced are called gametes (sperm in males and egg in females). By definition, a haploid cell contains only one set of chromosomes; therefore, the egg and sperm cells will not contain any homologous chromosomes.
Recall that mitosis is part of the cell cycle and that it is preceded by three phases: G1 phase, S phase, and G2 phase. Meiosis is immediately followed by the G2 phase. The main function of meiosis is to produce haploid gametes that can be used for sexual reproduction. Growth and repair of tissues in the human body is accomplished by mitosis, not meiosis.
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Which of the following processes occur in meiosis but do not occur in mitosis?
I. Spindle formation
II. Separation of homologous chromosomes
III. Separation of sister chromatids
IV. Recombination
Which of the following processes occur in meiosis but do not occur in mitosis?
I. Spindle formation
II. Separation of homologous chromosomes
III. Separation of sister chromatids
IV. Recombination
Mitosis and meiosis are similar processes that yield very different results. One of the major differences is that meiosis separates homologous chromosomes prior to separating sister chromatids. This is what leads to the reduction of ploidy. Both processes involve spindle formation (the microtubule apparatus that pulls the chromosomes/chromatids apart). Recombination is a phenomenon unique to meiosis that results in increasing genetic diversity.
Mitosis and meiosis are similar processes that yield very different results. One of the major differences is that meiosis separates homologous chromosomes prior to separating sister chromatids. This is what leads to the reduction of ploidy. Both processes involve spindle formation (the microtubule apparatus that pulls the chromosomes/chromatids apart). Recombination is a phenomenon unique to meiosis that results in increasing genetic diversity.
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The __________ is the site of attachment of spindle fibers to sister chromatids during mitosis.
The __________ is the site of attachment of spindle fibers to sister chromatids during mitosis.
Centrosomes are portions of the cell that help nucleate microtubules and form the mitotic spindle. Centrioles are composed of tubulin and are portions of the centrosome. The centromere is the portion of the chromosome where the two sister chromatids are linked. The kinetochore is a protein structure that helps associate the mitotic spindle to the sister chromatids. The outer portion of the kinetochore interacts with the microtubules, while the inner portion associates with the centromeric DNA.
Centrosomes are portions of the cell that help nucleate microtubules and form the mitotic spindle. Centrioles are composed of tubulin and are portions of the centrosome. The centromere is the portion of the chromosome where the two sister chromatids are linked. The kinetochore is a protein structure that helps associate the mitotic spindle to the sister chromatids. The outer portion of the kinetochore interacts with the microtubules, while the inner portion associates with the centromeric DNA.
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Which of the following occurs in mitosis, but does not occur in meiosis?
Which of the following occurs in mitosis, but does not occur in meiosis?
The main differences between meiosis and mitosis are that, during meiosis I, there is recombination between homologous chromosomes and the separation of homologous chromosomes. During mitosis, homologous chromosomes are not separated, only the sister chromatids. Both processes involve the breakdown of the nuclear envelope, allowing DNA to enter the cytoplasm and align at the equatorial plate and both processes involve separation of sister chromatids.
Only meiosis involves separation of homologous chromosomes. Since the question asks for an event exclusive to mitosis, none of these answers are suitable.
The main differences between meiosis and mitosis are that, during meiosis I, there is recombination between homologous chromosomes and the separation of homologous chromosomes. During mitosis, homologous chromosomes are not separated, only the sister chromatids. Both processes involve the breakdown of the nuclear envelope, allowing DNA to enter the cytoplasm and align at the equatorial plate and both processes involve separation of sister chromatids.
Only meiosis involves separation of homologous chromosomes. Since the question asks for an event exclusive to mitosis, none of these answers are suitable.
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Meiosis is a form of cell division that occurs in special types of cells called germ cells. It is different from mitosis because it takes a diploid cell and splits it into four, nonidentical haploid cells. In males, these haploid cells are called sperm and in females they are called eggs or ova. Meiosis has two steps: meiosis I and meiosis II. Both steps have their corresponding prophase, metaphase, anaphase, and telophase. Meiosis I phases are similar to mitotic phases, with a few key differences. Meiosis II phases are exactly identical to the mitotic phases.
A student is observing a set of cells under the microscope. He takes notes but forgets to write the mitotic phase for each slide. His notes are as follows.
Cell A: Site of ribosome synthesis disappears
Cell B: The nuclear content spills out into the cytoplasm
Cell C: No sister chromatids are visible
What is the mitotic phase of each cell?
Meiosis is a form of cell division that occurs in special types of cells called germ cells. It is different from mitosis because it takes a diploid cell and splits it into four, nonidentical haploid cells. In males, these haploid cells are called sperm and in females they are called eggs or ova. Meiosis has two steps: meiosis I and meiosis II. Both steps have their corresponding prophase, metaphase, anaphase, and telophase. Meiosis I phases are similar to mitotic phases, with a few key differences. Meiosis II phases are exactly identical to the mitotic phases.
A student is observing a set of cells under the microscope. He takes notes but forgets to write the mitotic phase for each slide. His notes are as follows.
Cell A: Site of ribosome synthesis disappears
Cell B: The nuclear content spills out into the cytoplasm
Cell C: No sister chromatids are visible
What is the mitotic phase of each cell?
There are four main phases in mitosis: prophase, metaphase, anaphase, and telophase. Prophase involves nuclear membrane breakdown, formation of mitotic spindle, and disappearance of nucleolus. Recall that nucleolus is the site of ribosome synthesis; therefore, cell A is in prophase. The question states that the nuclear contents are spilling out in Cell B. Nuclear membrane holds the contents of nucleus in place. During prophase, this nuclear membrane breaks down, causing the contents of the nucleus (like chromosomes) to spill out into the cytoplasm.
Metaphase involves the alignment of the chromosomes (with sister chromatids) along the equatorial line of the cell. In anaphase, the aligned chromosomes are pulled towards the opposite ends of the cell, causing the sister chromatids to separate. Finally, in telophase two distinct cell start appearing with chromosomes that have no sister chromatids; therefore, cell C must be in telophase.
Mitosis is immediately followed by cytokinesis, during which the cytoplasm is divided equally between the two daughter cells.
There are four main phases in mitosis: prophase, metaphase, anaphase, and telophase. Prophase involves nuclear membrane breakdown, formation of mitotic spindle, and disappearance of nucleolus. Recall that nucleolus is the site of ribosome synthesis; therefore, cell A is in prophase. The question states that the nuclear contents are spilling out in Cell B. Nuclear membrane holds the contents of nucleus in place. During prophase, this nuclear membrane breaks down, causing the contents of the nucleus (like chromosomes) to spill out into the cytoplasm.
Metaphase involves the alignment of the chromosomes (with sister chromatids) along the equatorial line of the cell. In anaphase, the aligned chromosomes are pulled towards the opposite ends of the cell, causing the sister chromatids to separate. Finally, in telophase two distinct cell start appearing with chromosomes that have no sister chromatids; therefore, cell C must be in telophase.
Mitosis is immediately followed by cytokinesis, during which the cytoplasm is divided equally between the two daughter cells.
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