Wilkes University NSG 530 Advanced Pathophysiology Exam 1 (pdf) |
2026/2027 | Patho Q&A | Pathophysiology
1. A newborn is diagnosed with Down syndrome. Which chromosomal
abnormality is responsible?
A) Trisomy 13
B) Trisomy 18
C) Trisomy 21
D) Monosomy X
Correct Answer: Trisomy 21
Rationale: Down syndrome is caused by an extra copy of chromosome 21
(trisomy 21), leading to characteristic physical features, intellectual
disability, and congenital abnormalities. Trisomy 13 (Patau syndrome) and
trisomy 18 (Edwards syndrome) are associated with different clinical
presentations, and monosomy X results in Turner syndrome.
2. A nondisjunction event occurs during oogenesis. Which chromosomal
abnormalities may result?
A) Point mutations only
B) Monosomy and trisomy
C) Deletions only
D) Gene amplification
Correct Answer: Monosomy and trisomy
Rationale: Nondisjunction is the failure of homologous chromosomes or sister
chromatids to separate properly during meiosis, resulting in gametes with an
abnormal number of chromosomes. Fertilization can produce monosomy
,(missing a chromosome) or trisomy (an extra chromosome). Point mutations,
deletions, and gene amplification are different types of genetic alterations.
3. A heterozygous individual has:
A) Two identical alleles
B) One allele only
C) Two different alleles
D) No alleles
Correct Answer: Two different alleles
Rationale: Heterozygosity refers to the presence of two different alleles at a
gene locus. Homozygous individuals have two identical alleles. The other
options do not accurately describe heterozygosity.
4. A couple has two children: one affected with an autosomal recessive
disorder and one unaffected. What is the most likely genetic status of the
parents?
A) One parent is affected, the other is normal
B) Both parents are carriers
C) Both parents are affected
D) Neither parent carries the gene
Correct Answer: Both parents are carriers
Rationale: Autosomal recessive disorders require both parents to contribute a
mutated allele. The most likely explanation for one affected and one
unaffected child is that both parents are asymptomatic carriers of the gene.
If one parent were affected and the other normal, all children would be
,carriers (not affected). If both parents were affected, all children would be
affected.
5. Understand the process of meiosis related to homologous chromosomes.
During meiosis, homologous chromosomes separate during which phase?
A) Prophase I
B) Metaphase I
C) Anaphase I
D) Telophase II
Correct Answer: Anaphase I
Rationale: During Anaphase I of meiosis, homologous chromosomes (each
consisting of two sister chromatids) are pulled to opposite poles of the cell.
This reductional division reduces the chromosome number from diploid to
haploid. Sister chromatids separate during Anaphase II.
6. Define chromosomal mosaic. Which statement best describes a
chromosomal mosaic?
A) An individual with two or more cell lines differing in chromosome
composition
B) An individual with an extra chromosome in all cells
C) An individual missing a chromosome in all cells
D) An individual with a single gene mutation
Correct Answer: An individual with two or more cell lines differing in
chromosome composition
Rationale: A chromosomal mosaic is an individual who has two or more cell
populations with different chromosomal constitutions, derived from a single
, zygote. This occurs due to mitotic errors after fertilization. The other options
describe different genetic conditions.
7. Which of the following is a characteristic feature of Cri du chat syndrome?
A) Extra chromosome 21
B) Deletion of short arm of chromosome 5
C) Fragile site on X chromosome
D) Extra X chromosome in males
Correct Answer: Deletion of short arm of chromosome 5
Rationale: Cri du chat (cat's cry) syndrome is caused by a deletion on the
short arm of chromosome 5 (5p-). Characteristics include a high-pitched, cat-
like cry, microcephaly, and severe intellectual disability. The other options
correspond to Down syndrome, Fragile X, and Klinefelter syndrome.
8. A male patient presents with tall stature, gynecomastia, small testes, and
infertility. Which genetic disorder is most likely?
A) Turner syndrome
B) Klinefelter syndrome
C) Fragile X syndrome
D) Duchenne muscular dystrophy
Correct Answer: Klinefelter syndrome
Rationale: Klinefelter syndrome (47,XXY) is characterized by tall stature,
gynecomastia, small firm testes, and infertility. Turner syndrome (45,X)
affects females. Fragile X syndrome is associated with intellectual disability
and characteristic facial features. Duchenne muscular dystrophy presents
with progressive muscle weakness.
2026/2027 | Patho Q&A | Pathophysiology
1. A newborn is diagnosed with Down syndrome. Which chromosomal
abnormality is responsible?
A) Trisomy 13
B) Trisomy 18
C) Trisomy 21
D) Monosomy X
Correct Answer: Trisomy 21
Rationale: Down syndrome is caused by an extra copy of chromosome 21
(trisomy 21), leading to characteristic physical features, intellectual
disability, and congenital abnormalities. Trisomy 13 (Patau syndrome) and
trisomy 18 (Edwards syndrome) are associated with different clinical
presentations, and monosomy X results in Turner syndrome.
2. A nondisjunction event occurs during oogenesis. Which chromosomal
abnormalities may result?
A) Point mutations only
B) Monosomy and trisomy
C) Deletions only
D) Gene amplification
Correct Answer: Monosomy and trisomy
Rationale: Nondisjunction is the failure of homologous chromosomes or sister
chromatids to separate properly during meiosis, resulting in gametes with an
abnormal number of chromosomes. Fertilization can produce monosomy
,(missing a chromosome) or trisomy (an extra chromosome). Point mutations,
deletions, and gene amplification are different types of genetic alterations.
3. A heterozygous individual has:
A) Two identical alleles
B) One allele only
C) Two different alleles
D) No alleles
Correct Answer: Two different alleles
Rationale: Heterozygosity refers to the presence of two different alleles at a
gene locus. Homozygous individuals have two identical alleles. The other
options do not accurately describe heterozygosity.
4. A couple has two children: one affected with an autosomal recessive
disorder and one unaffected. What is the most likely genetic status of the
parents?
A) One parent is affected, the other is normal
B) Both parents are carriers
C) Both parents are affected
D) Neither parent carries the gene
Correct Answer: Both parents are carriers
Rationale: Autosomal recessive disorders require both parents to contribute a
mutated allele. The most likely explanation for one affected and one
unaffected child is that both parents are asymptomatic carriers of the gene.
If one parent were affected and the other normal, all children would be
,carriers (not affected). If both parents were affected, all children would be
affected.
5. Understand the process of meiosis related to homologous chromosomes.
During meiosis, homologous chromosomes separate during which phase?
A) Prophase I
B) Metaphase I
C) Anaphase I
D) Telophase II
Correct Answer: Anaphase I
Rationale: During Anaphase I of meiosis, homologous chromosomes (each
consisting of two sister chromatids) are pulled to opposite poles of the cell.
This reductional division reduces the chromosome number from diploid to
haploid. Sister chromatids separate during Anaphase II.
6. Define chromosomal mosaic. Which statement best describes a
chromosomal mosaic?
A) An individual with two or more cell lines differing in chromosome
composition
B) An individual with an extra chromosome in all cells
C) An individual missing a chromosome in all cells
D) An individual with a single gene mutation
Correct Answer: An individual with two or more cell lines differing in
chromosome composition
Rationale: A chromosomal mosaic is an individual who has two or more cell
populations with different chromosomal constitutions, derived from a single
, zygote. This occurs due to mitotic errors after fertilization. The other options
describe different genetic conditions.
7. Which of the following is a characteristic feature of Cri du chat syndrome?
A) Extra chromosome 21
B) Deletion of short arm of chromosome 5
C) Fragile site on X chromosome
D) Extra X chromosome in males
Correct Answer: Deletion of short arm of chromosome 5
Rationale: Cri du chat (cat's cry) syndrome is caused by a deletion on the
short arm of chromosome 5 (5p-). Characteristics include a high-pitched, cat-
like cry, microcephaly, and severe intellectual disability. The other options
correspond to Down syndrome, Fragile X, and Klinefelter syndrome.
8. A male patient presents with tall stature, gynecomastia, small testes, and
infertility. Which genetic disorder is most likely?
A) Turner syndrome
B) Klinefelter syndrome
C) Fragile X syndrome
D) Duchenne muscular dystrophy
Correct Answer: Klinefelter syndrome
Rationale: Klinefelter syndrome (47,XXY) is characterized by tall stature,
gynecomastia, small firm testes, and infertility. Turner syndrome (45,X)
affects females. Fragile X syndrome is associated with intellectual disability
and characteristic facial features. Duchenne muscular dystrophy presents
with progressive muscle weakness.
