Genes and Chromosomes - MCAT Biological and Biochemical Foundations of Living Systems
Card 1 of 56
A diploid human cell that is dividing will contain chromosomes. These chromosomes will each consist of chromatids. Fill in the corresponding blanks.
A diploid human cell that is dividing will contain chromosomes. These chromosomes will each consist of chromatids. Fill in the corresponding blanks.
Tap to reveal answer
The diploid number is 46 and the haploid number is 23. When cells are dividing, each chromosome is present in duplicate copy. These chromosomes are composed of two chromatids each when they are replicated.
The diploid number is 46 and the haploid number is 23. When cells are dividing, each chromosome is present in duplicate copy. These chromosomes are composed of two chromatids each when they are replicated.
← Didn't Know|Knew It →
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.
In der(14,21), which region of a chromosome might you expect to find in the center of its structure?
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.
In der(14,21), which region of a chromosome might you expect to find in the center of its structure?
Tap to reveal answer
Telomeres are present at the ends of chromosomes. If one really understands the passage, one can see that Robertsonian translocation places the ends of chromosomes together to form the middle of the derivative chromosome. We would expect to find telomeres in this region.
Telomeres are present at the ends of chromosomes. If one really understands the passage, one can see that Robertsonian translocation places the ends of chromosomes together to form the middle of the derivative chromosome. We would expect to find telomeres in this region.
← Didn't Know|Knew It →
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.
In a normal chromosome 14, what region of the chromosome exists between the p arm and the q arm?
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.
In a normal chromosome 14, what region of the chromosome exists between the p arm and the q arm?
Tap to reveal answer
In a normal chromosome, the passage indicates that the p and q arm meet in the center. This central region of the chromosome is known as a centromere.
In a normal chromosome, the passage indicates that the p and q arm meet in the center. This central region of the chromosome is known as a centromere.
← Didn't Know|Knew It →
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.
Chromosome 15 is an autosome. Which of the following is (are) true of all autosomes?
I. They contain histones
II. They determine chromosomal sex
III. They align on the metaphase plate during mitosis
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.
Chromosome 15 is an autosome. Which of the following is (are) true of all autosomes?
I. They contain histones
II. They determine chromosomal sex
III. They align on the metaphase plate during mitosis
Tap to reveal answer
Autosomes are the chromosomes that are not sex chromosomes. Any numbered chromosome (1 through 22) is an autosome, while the X and Y chromosomes (the 23rd pair) are the sex chromosomes. Statement II is only true of the X and Y chromosomes. Statements I and III are true of all chromosomes.
Autosomes are the chromosomes that are not sex chromosomes. Any numbered chromosome (1 through 22) is an autosome, while the X and Y chromosomes (the 23rd pair) are the sex chromosomes. Statement II is only true of the X and Y chromosomes. Statements I and III are true of all chromosomes.
← Didn't Know|Knew It →
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.
Imagine the child in figure 1 was diagnosed at birth with cystic fibrosis as well as Prader-Willi. Cystic fibrosis is due to a recessive genetic mutation on chromosome 7. Two years later, his parents have another child that has cystic fibrosis, but not Prader-Willi. Which of the following best explains why Prader-Willi and cystic fibrosis are not always inherited together ?
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.
Imagine the child in figure 1 was diagnosed at birth with cystic fibrosis as well as Prader-Willi. Cystic fibrosis is due to a recessive genetic mutation on chromosome 7. Two years later, his parents have another child that has cystic fibrosis, but not Prader-Willi. Which of the following best explains why Prader-Willi and cystic fibrosis are not always inherited together ?
Tap to reveal answer
The law of independent assortment says that chromosomes, and thus most genes, align independently of each other when being passed from parent to child. In other words, chromosome 7 and chromosome 15 do not directly influence each other's inheritance patterns during meiosis in parental gametes, and can be sent to sperm or eggs in any combination.
The law of independent assortment says that chromosomes, and thus most genes, align independently of each other when being passed from parent to child. In other words, chromosome 7 and chromosome 15 do not directly influence each other's inheritance patterns during meiosis in parental gametes, and can be sent to sperm or eggs in any combination.
← Didn't Know|Knew It →
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.
Based on the information in the passage, which of the following is true of Prader-Willi Syndrome?
I. It must involve a chromosomal deletion on the paternal chromosome 15
II. It must involve normal silencing of maternal chromosome 15
III. It is a sex-linked disorder because it involves chromosome 15
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.
Based on the information in the passage, which of the following is true of Prader-Willi Syndrome?
I. It must involve a chromosomal deletion on the paternal chromosome 15
II. It must involve normal silencing of maternal chromosome 15
III. It is a sex-linked disorder because it involves chromosome 15
Tap to reveal answer
Prader-Willi must involve the silencing of maternal genes on chromosome 15, as well as some disruption of the paternal chromosome. A chromosomal deletion is one example of this kind of disruption, but could also be a nonsense mutation or frameshift mutation that renders the paternal DNA unable to be ultimately translated to protein.
Sex-linked disorders involve the X and Y chromosomes. Prader-Willi is inherited through chromosome 15, and is thus not sex-linked.
Prader-Willi must involve the silencing of maternal genes on chromosome 15, as well as some disruption of the paternal chromosome. A chromosomal deletion is one example of this kind of disruption, but could also be a nonsense mutation or frameshift mutation that renders the paternal DNA unable to be ultimately translated to protein.
Sex-linked disorders involve the X and Y chromosomes. Prader-Willi is inherited through chromosome 15, and is thus not sex-linked.
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A man with type AB blood marries a woman with type A blood. Which of the following blood types might their sons inherit?
A man with type AB blood marries a woman with type A blood. Which of the following blood types might their sons inherit?
Tap to reveal answer
The genotype of the father is definitely AB. The genotype of the mother is either AA or AO.
Below are the Punnett squares that show that types A, B, and AB are possible. Note that the genotype AO will result in a type A phenotype, while the genotype BO will result in a type B phenotype.
The genotype of the father is definitely AB. The genotype of the mother is either AA or AO.
Below are the Punnett squares that show that types A, B, and AB are possible. Note that the genotype AO will result in a type A phenotype, while the genotype BO will result in a type B phenotype.
← Didn't Know|Knew It →
A diploid human cell that is dividing will contain chromosomes. These chromosomes will each consist of chromatids. Fill in the corresponding blanks.
A diploid human cell that is dividing will contain chromosomes. These chromosomes will each consist of chromatids. Fill in the corresponding blanks.
Tap to reveal answer
The diploid number is 46 and the haploid number is 23. When cells are dividing, each chromosome is present in duplicate copy. These chromosomes are composed of two chromatids each when they are replicated.
The diploid number is 46 and the haploid number is 23. When cells are dividing, each chromosome is present in duplicate copy. These chromosomes are composed of two chromatids each when they are replicated.
← Didn't Know|Knew It →
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.
In der(14,21), which region of a chromosome might you expect to find in the center of its structure?
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.
In der(14,21), which region of a chromosome might you expect to find in the center of its structure?
Tap to reveal answer
Telomeres are present at the ends of chromosomes. If one really understands the passage, one can see that Robertsonian translocation places the ends of chromosomes together to form the middle of the derivative chromosome. We would expect to find telomeres in this region.
Telomeres are present at the ends of chromosomes. If one really understands the passage, one can see that Robertsonian translocation places the ends of chromosomes together to form the middle of the derivative chromosome. We would expect to find telomeres in this region.
← Didn't Know|Knew It →
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.
In a normal chromosome 14, what region of the chromosome exists between the p arm and the q arm?
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.
In a normal chromosome 14, what region of the chromosome exists between the p arm and the q arm?
Tap to reveal answer
In a normal chromosome, the passage indicates that the p and q arm meet in the center. This central region of the chromosome is known as a centromere.
In a normal chromosome, the passage indicates that the p and q arm meet in the center. This central region of the chromosome is known as a centromere.
← Didn't Know|Knew It →
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.
Chromosome 15 is an autosome. Which of the following is (are) true of all autosomes?
I. They contain histones
II. They determine chromosomal sex
III. They align on the metaphase plate during mitosis
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.
Chromosome 15 is an autosome. Which of the following is (are) true of all autosomes?
I. They contain histones
II. They determine chromosomal sex
III. They align on the metaphase plate during mitosis
Tap to reveal answer
Autosomes are the chromosomes that are not sex chromosomes. Any numbered chromosome (1 through 22) is an autosome, while the X and Y chromosomes (the 23rd pair) are the sex chromosomes. Statement II is only true of the X and Y chromosomes. Statements I and III are true of all chromosomes.
Autosomes are the chromosomes that are not sex chromosomes. Any numbered chromosome (1 through 22) is an autosome, while the X and Y chromosomes (the 23rd pair) are the sex chromosomes. Statement II is only true of the X and Y chromosomes. Statements I and III are true of all chromosomes.
← Didn't Know|Knew It →
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.
Imagine the child in figure 1 was diagnosed at birth with cystic fibrosis as well as Prader-Willi. Cystic fibrosis is due to a recessive genetic mutation on chromosome 7. Two years later, his parents have another child that has cystic fibrosis, but not Prader-Willi. Which of the following best explains why Prader-Willi and cystic fibrosis are not always inherited together ?
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.
Imagine the child in figure 1 was diagnosed at birth with cystic fibrosis as well as Prader-Willi. Cystic fibrosis is due to a recessive genetic mutation on chromosome 7. Two years later, his parents have another child that has cystic fibrosis, but not Prader-Willi. Which of the following best explains why Prader-Willi and cystic fibrosis are not always inherited together ?
Tap to reveal answer
The law of independent assortment says that chromosomes, and thus most genes, align independently of each other when being passed from parent to child. In other words, chromosome 7 and chromosome 15 do not directly influence each other's inheritance patterns during meiosis in parental gametes, and can be sent to sperm or eggs in any combination.
The law of independent assortment says that chromosomes, and thus most genes, align independently of each other when being passed from parent to child. In other words, chromosome 7 and chromosome 15 do not directly influence each other's inheritance patterns during meiosis in parental gametes, and can be sent to sperm or eggs in any combination.
← Didn't Know|Knew It →
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.
Based on the information in the passage, which of the following is true of Prader-Willi Syndrome?
I. It must involve a chromosomal deletion on the paternal chromosome 15
II. It must involve normal silencing of maternal chromosome 15
III. It is a sex-linked disorder because it involves chromosome 15
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.
Based on the information in the passage, which of the following is true of Prader-Willi Syndrome?
I. It must involve a chromosomal deletion on the paternal chromosome 15
II. It must involve normal silencing of maternal chromosome 15
III. It is a sex-linked disorder because it involves chromosome 15
Tap to reveal answer
Prader-Willi must involve the silencing of maternal genes on chromosome 15, as well as some disruption of the paternal chromosome. A chromosomal deletion is one example of this kind of disruption, but could also be a nonsense mutation or frameshift mutation that renders the paternal DNA unable to be ultimately translated to protein.
Sex-linked disorders involve the X and Y chromosomes. Prader-Willi is inherited through chromosome 15, and is thus not sex-linked.
Prader-Willi must involve the silencing of maternal genes on chromosome 15, as well as some disruption of the paternal chromosome. A chromosomal deletion is one example of this kind of disruption, but could also be a nonsense mutation or frameshift mutation that renders the paternal DNA unable to be ultimately translated to protein.
Sex-linked disorders involve the X and Y chromosomes. Prader-Willi is inherited through chromosome 15, and is thus not sex-linked.
← Didn't Know|Knew It →
A man with type AB blood marries a woman with type A blood. Which of the following blood types might their sons inherit?
A man with type AB blood marries a woman with type A blood. Which of the following blood types might their sons inherit?
Tap to reveal answer
The genotype of the father is definitely AB. The genotype of the mother is either AA or AO.
Below are the Punnett squares that show that types A, B, and AB are possible. Note that the genotype AO will result in a type A phenotype, while the genotype BO will result in a type B phenotype.
The genotype of the father is definitely AB. The genotype of the mother is either AA or AO.
Below are the Punnett squares that show that types A, B, and AB are possible. Note that the genotype AO will result in a type A phenotype, while the genotype BO will result in a type B phenotype.
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A diploid human cell that is dividing will contain chromosomes. These chromosomes will each consist of chromatids. Fill in the corresponding blanks.
A diploid human cell that is dividing will contain chromosomes. These chromosomes will each consist of chromatids. Fill in the corresponding blanks.
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The diploid number is 46 and the haploid number is 23. When cells are dividing, each chromosome is present in duplicate copy. These chromosomes are composed of two chromatids each when they are replicated.
The diploid number is 46 and the haploid number is 23. When cells are dividing, each chromosome is present in duplicate copy. These chromosomes are composed of two chromatids each when they are replicated.
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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.
In der(14,21), which region of a chromosome might you expect to find in the center of its structure?
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.
In der(14,21), which region of a chromosome might you expect to find in the center of its structure?
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Telomeres are present at the ends of chromosomes. If one really understands the passage, one can see that Robertsonian translocation places the ends of chromosomes together to form the middle of the derivative chromosome. We would expect to find telomeres in this region.
Telomeres are present at the ends of chromosomes. If one really understands the passage, one can see that Robertsonian translocation places the ends of chromosomes together to form the middle of the derivative chromosome. We would expect to find telomeres in this region.
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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.
In a normal chromosome 14, what region of the chromosome exists between the p arm and the q arm?
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.
In a normal chromosome 14, what region of the chromosome exists between the p arm and the q arm?
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In a normal chromosome, the passage indicates that the p and q arm meet in the center. This central region of the chromosome is known as a centromere.
In a normal chromosome, the passage indicates that the p and q arm meet in the center. This central region of the chromosome is known as a centromere.
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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.
Chromosome 15 is an autosome. Which of the following is (are) true of all autosomes?
I. They contain histones
II. They determine chromosomal sex
III. They align on the metaphase plate during mitosis
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.
Chromosome 15 is an autosome. Which of the following is (are) true of all autosomes?
I. They contain histones
II. They determine chromosomal sex
III. They align on the metaphase plate during mitosis
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Autosomes are the chromosomes that are not sex chromosomes. Any numbered chromosome (1 through 22) is an autosome, while the X and Y chromosomes (the 23rd pair) are the sex chromosomes. Statement II is only true of the X and Y chromosomes. Statements I and III are true of all chromosomes.
Autosomes are the chromosomes that are not sex chromosomes. Any numbered chromosome (1 through 22) is an autosome, while the X and Y chromosomes (the 23rd pair) are the sex chromosomes. Statement II is only true of the X and Y chromosomes. Statements I and III are true of all chromosomes.
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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.
Imagine the child in figure 1 was diagnosed at birth with cystic fibrosis as well as Prader-Willi. Cystic fibrosis is due to a recessive genetic mutation on chromosome 7. Two years later, his parents have another child that has cystic fibrosis, but not Prader-Willi. Which of the following best explains why Prader-Willi and cystic fibrosis are not always inherited together ?
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.
Imagine the child in figure 1 was diagnosed at birth with cystic fibrosis as well as Prader-Willi. Cystic fibrosis is due to a recessive genetic mutation on chromosome 7. Two years later, his parents have another child that has cystic fibrosis, but not Prader-Willi. Which of the following best explains why Prader-Willi and cystic fibrosis are not always inherited together ?
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The law of independent assortment says that chromosomes, and thus most genes, align independently of each other when being passed from parent to child. In other words, chromosome 7 and chromosome 15 do not directly influence each other's inheritance patterns during meiosis in parental gametes, and can be sent to sperm or eggs in any combination.
The law of independent assortment says that chromosomes, and thus most genes, align independently of each other when being passed from parent to child. In other words, chromosome 7 and chromosome 15 do not directly influence each other's inheritance patterns during meiosis in parental gametes, and can be sent to sperm or eggs in any combination.
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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.
Based on the information in the passage, which of the following is true of Prader-Willi Syndrome?
I. It must involve a chromosomal deletion on the paternal chromosome 15
II. It must involve normal silencing of maternal chromosome 15
III. It is a sex-linked disorder because it involves chromosome 15
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.
Based on the information in the passage, which of the following is true of Prader-Willi Syndrome?
I. It must involve a chromosomal deletion on the paternal chromosome 15
II. It must involve normal silencing of maternal chromosome 15
III. It is a sex-linked disorder because it involves chromosome 15
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Prader-Willi must involve the silencing of maternal genes on chromosome 15, as well as some disruption of the paternal chromosome. A chromosomal deletion is one example of this kind of disruption, but could also be a nonsense mutation or frameshift mutation that renders the paternal DNA unable to be ultimately translated to protein.
Sex-linked disorders involve the X and Y chromosomes. Prader-Willi is inherited through chromosome 15, and is thus not sex-linked.
Prader-Willi must involve the silencing of maternal genes on chromosome 15, as well as some disruption of the paternal chromosome. A chromosomal deletion is one example of this kind of disruption, but could also be a nonsense mutation or frameshift mutation that renders the paternal DNA unable to be ultimately translated to protein.
Sex-linked disorders involve the X and Y chromosomes. Prader-Willi is inherited through chromosome 15, and is thus not sex-linked.
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