PRIN401 WEEK 2
N/a
N/a
Where is ribosomal RNA (rRNA) synthesized?
nucleolus
During which of the following stages are synaptonemal complexes formed?
Meiotic prophase I
When do pairs of sister chromatids separate from one another? (in mitosis and meiosis)
Mitosis Anaphase and Meiosis anaphase II
Which of the following statement(s) is/are true regarding the process of oogenesis?
- Each meiotic event produces one functional gamete and the other potential gametes undergo cell death.
- Each meiotic event produces two functional gametes, as the number of chromosomes is reduced by one half.
- Meiosis begins at the time of puberty and continues throughout reproductive life.
- Meiosis occurs in the seminiferous tubules and the eggs are stored until ovulation.
- Pairing and recombination between chromosomes during oogenesis occurs in fetal life.
1 and 5.
The standard karyotype is produced by using many cells at which stages?
Cytogenetic analysis is performed on condensed chromosomes, e.g. in metaphase or prometaphase.
A 29-year old woman had a first trimester spontaneous abortion. Cytogenetic analysis of cultured cells from the aborted embryo showed an abnormal karyotype. What would be a most likely type of abnormal cytogenetic finding in this specimen?
In spontaneous abortions, cytogenetic analysis of the embryonic specimens has revealed that 60-70% are chromosomally abnormal. The frequency of chromosome abnormalities include 50% trisomies, 20% monosomies, and 23% triploidies and tetraploidies. Among such early losses, the commonest trisomy is of chromosome 16.
he child in the following pedigree has Down syndrome caused by trisomy 21. The chromosome analysis below the pedigree uses a chromosome 21-specific DNA polymorphism. Which of the following statements is true?
The child has a balanced reciprocal translocation.
The child has a Robertsonian translocation.
The mother has a Robertsonian translocation.
There was an error in oogenesis.
There was an error in spermatogenesis.
a) If this were the case, the child would not have Down syndrome. The child would most likely have a normal phenotype.
b) The question stem states that the child's Down syndrome is due to trisomy 21, not a Robertsonian translocation.
c) While it is possible for this banding pattern to occur in a Robertsonian translocation, this is not the correct answer because in this case, the child's Down syndrome would be due to a Robertsonian translocation and not actually trisomy 21 (which is, strictly speaking, three copies of chromosome 21).
How is it possible for this banding pattern to be from a Robertsonian translocation? Consider the mother's two bands. One of these bands is from the mother's normal chromosome 21 and the other band is from the chromosome 21 that is part of the Robertsonian translocation. The child has three bands because he/she has inherited both the normal chromosome 21 and the Robertsonian chromosome (with chromosome 21 on it) from the mother, as well as one of the father's chromosome 21s.
*d) This is correct. The child inherited two chromosome 21s from the mother, which should normally not be the case. This is represented by the fact that the child's banding pattern includes the two bands that the mother has.
e) There is no evidence of this in the chromosome analysis.
What is the recurrence risk in future pregnancies for each of the following patients who had a chromosomally abnormal pregnancy compared to an average person (or population risk)?
A 26-year old father with a translocation of chromosomes 14 and 21
Selected Answer:
Increased risk
Answers:
Increased risk
Unchanged risk
Decreased risk
Cannot be determined
Increased. A man who has Rob translocation is at 2% risk for getting affected kids. If it's a woman, 10 % risk
What is the recurrence risk in future pregnancies for each of the following patients who had a chromosomally abnormal pregnancy compared to an average person (or population risk)?
A 26-year old father with a translocation of chromosomes 14 and 21
Selected Answer:
Increased risk
Answers:
Increased risk
Unchanged risk
Decreased risk
Cannot be determined
Increased. A man who has Rob translocation is at 2% risk for getting affected kids. If it's a woman, 10 % risk
What is the recurrence risk in future pregnancies for each of the following patients who had a chromosomally abnormal pregnancy compared to an average person (or population risk)?
A 21 year old woman with a spontaneous abortion with triploidy
Increased risk
Unchanged risk
Decreased risk
Cannot be determine
Triploidy is a common cause of early spontaneous abortion, but is a sporadic event and is not associated with an increased risk in future pregnancies, nor does the frequency increase with the age of the mother.
Ans is unchanged, because triploidy is a sporadic event. It is different from trisomy, in that trisomy has 47 chromosomes, whereas triploidy has an extra set of genes, which is 69 chromosomes.
A 41-year old woman had a spontaneous abortion due to trisomy 13. What is the risk that she will have another pregnancy with a trisomy?
For a woman over 35 years of age, the risk of having another (i.e. any trisomy) trisomy is age-related risk. For a woman below 35 years of age, the risk of having another trisomy is 1-2%.
A 41-year old woman has a pericentric inversion in one of her chromosomes. What is the chance that she will give birth to a child with a chromosomal imbalance because of this inversion?
A parent with an inversion will have a 5-10% risk of having a child with an inversion.
A family seeks your urgent advice. The 30-year old woman is pregnant and she is concerned because her brother has Down syndrome. As her family doctor, which of the following would you recommend as the first appropriate step?
A newborn was suspected to have Prader-Willi syndrome, a microdeletion syndrome. Which type of cytogenetic testing would MOST LIKELY be ordered to determine whether the patient has this deletion?
anaphase lag may result in _____ syndrome. The recurrence risk is not increased, because anaphase lag is __________. It is not associated with ______ age.
Turner.
sporadic
maternal.
what is the risk of getting an unbalanced translocation from a reciprocal translocation carrier?
30-40% (doing a normal segration diagram of a reciprocal balanced translocation carrier with a normal parent, you would think the chance is 50%, but the observed rate is lower)
what are the 6 indicators of karyotyping? (mnemonic)
mnemonic: IF FAST, you might save the baby
Infertility
Failure to Thrive
Family history
Advanced age of mum (you test the fetus)
Stillbirth and miscarriages
Tumor
-
- 1 / 17
-
Lernkarten
Where is ribosomal RNA (rRNA) synthesized?
nucleolus
During which of the following stages are synaptonemal complexes formed?
Meiotic prophase I
When do pairs of sister chromatids separate from one another? (in mitosis and meiosis)
Mitosis Anaphase and Meiosis anaphase II
Which of the following statement(s) is/are true regarding the process of oogenesis?
- Each meiotic event produces one functional gamete and the other potential gametes undergo cell death.
- Each meiotic event produces two functional gametes, as the number of chromosomes is reduced by one half.
- Meiosis begins at the time of puberty and continues throughout reproductive life.
- Meiosis occurs in the seminiferous tubules and the eggs are stored until ovulation.
- Pairing and recombination between chromosomes during oogenesis occurs in fetal life.
1 and 5.
The standard karyotype is produced by using many cells at which stages?
Cytogenetic analysis is performed on condensed chromosomes, e.g. in metaphase or prometaphase.
A 29-year old woman had a first trimester spontaneous abortion. Cytogenetic analysis of cultured cells from the aborted embryo showed an abnormal karyotype. What would be a most likely type of abnormal cytogenetic finding in this specimen?
In spontaneous abortions, cytogenetic analysis of the embryonic specimens has revealed that 60-70% are chromosomally abnormal. The frequency of chromosome abnormalities include 50% trisomies, 20% monosomies, and 23% triploidies and tetraploidies. Among such early losses, the commonest trisomy is of chromosome 16.
he child in the following pedigree has Down syndrome caused by trisomy 21. The chromosome analysis below the pedigree uses a chromosome 21-specific DNA polymorphism. Which of the following statements is true?
The child has a balanced reciprocal translocation.
The child has a Robertsonian translocation.
The mother has a Robertsonian translocation.
There was an error in oogenesis.
There was an error in spermatogenesis.
a) If this were the case, the child would not have Down syndrome. The child would most likely have a normal phenotype.
b) The question stem states that the child's Down syndrome is due to trisomy 21, not a Robertsonian translocation.
c) While it is possible for this banding pattern to occur in a Robertsonian translocation, this is not the correct answer because in this case, the child's Down syndrome would be due to a Robertsonian translocation and not actually trisomy 21 (which is, strictly speaking, three copies of chromosome 21).
How is it possible for this banding pattern to be from a Robertsonian translocation? Consider the mother's two bands. One of these bands is from the mother's normal chromosome 21 and the other band is from the chromosome 21 that is part of the Robertsonian translocation. The child has three bands because he/she has inherited both the normal chromosome 21 and the Robertsonian chromosome (with chromosome 21 on it) from the mother, as well as one of the father's chromosome 21s.
*d) This is correct. The child inherited two chromosome 21s from the mother, which should normally not be the case. This is represented by the fact that the child's banding pattern includes the two bands that the mother has.
e) There is no evidence of this in the chromosome analysis.
What is the recurrence risk in future pregnancies for each of the following patients who had a chromosomally abnormal pregnancy compared to an average person (or population risk)?
A 26-year old father with a translocation of chromosomes 14 and 21
Selected Answer:
Increased risk
Answers:
Increased risk
Unchanged risk
Decreased risk
Cannot be determined
Increased. A man who has Rob translocation is at 2% risk for getting affected kids. If it's a woman, 10 % risk
What is the recurrence risk in future pregnancies for each of the following patients who had a chromosomally abnormal pregnancy compared to an average person (or population risk)?
A 26-year old father with a translocation of chromosomes 14 and 21
Selected Answer:
Increased risk
Answers:
Increased risk
Unchanged risk
Decreased risk
Cannot be determined
Increased. A man who has Rob translocation is at 2% risk for getting affected kids. If it's a woman, 10 % risk
What is the recurrence risk in future pregnancies for each of the following patients who had a chromosomally abnormal pregnancy compared to an average person (or population risk)?
A 21 year old woman with a spontaneous abortion with triploidy
Increased risk
Unchanged risk
Decreased risk
Cannot be determine
Triploidy is a common cause of early spontaneous abortion, but is a sporadic event and is not associated with an increased risk in future pregnancies, nor does the frequency increase with the age of the mother.
Ans is unchanged, because triploidy is a sporadic event. It is different from trisomy, in that trisomy has 47 chromosomes, whereas triploidy has an extra set of genes, which is 69 chromosomes.
A 41-year old woman had a spontaneous abortion due to trisomy 13. What is the risk that she will have another pregnancy with a trisomy?
For a woman over 35 years of age, the risk of having another (i.e. any trisomy) trisomy is age-related risk. For a woman below 35 years of age, the risk of having another trisomy is 1-2%.
A 41-year old woman has a pericentric inversion in one of her chromosomes. What is the chance that she will give birth to a child with a chromosomal imbalance because of this inversion?
A parent with an inversion will have a 5-10% risk of having a child with an inversion.
A family seeks your urgent advice. The 30-year old woman is pregnant and she is concerned because her brother has Down syndrome. As her family doctor, which of the following would you recommend as the first appropriate step?
A newborn was suspected to have Prader-Willi syndrome, a microdeletion syndrome. Which type of cytogenetic testing would MOST LIKELY be ordered to determine whether the patient has this deletion?
anaphase lag may result in _____ syndrome. The recurrence risk is not increased, because anaphase lag is __________. It is not associated with ______ age.
Turner.
sporadic
maternal.
what is the risk of getting an unbalanced translocation from a reciprocal translocation carrier?
30-40% (doing a normal segration diagram of a reciprocal balanced translocation carrier with a normal parent, you would think the chance is 50%, but the observed rate is lower)
what are the 6 indicators of karyotyping? (mnemonic)
mnemonic: IF FAST, you might save the baby
Infertility
Failure to Thrive
Family history
Advanced age of mum (you test the fetus)
Stillbirth and miscarriages
Tumor
