Part 7: Chromosomal Disorders in Humans (25 MCQs)
Part 7: Chromosomal Disorders in Humans (25 MCQs)
Q151. Chromosomal disorders arise due to:
a) Single gene mutations
b) Abnormalities in chromosome number or structure
c) Environmental stress
d) Protein misfolding
Answer: b
- b) Correct: Chromosomal disorders = numerical or structural chromosome abnormalities.
- a) Single gene disorders = Mendelian.
- c, d) Not direct causes.
Q152. Down’s syndrome is caused due to:
a) Monosomy of X chromosome
b) Trisomy of chromosome 21
c) Trisomy of chromosome 18
d) Duplication of Y chromosome
Answer: b
- b) Correct: Down’s = trisomy 21.
Q153. The genetic formula for Down’s syndrome is:
a) 45, XO
b) 47, XX or XY +21
c) 47, XXY
d) 46, XY
Answer: b
- b) Correct: Down’s = 47 chromosomes (extra 21).
Q154. Symptoms of Down’s syndrome include:
a) Flat face, mental retardation, short stature
b) Tall stature, breast enlargement
c) Webbed neck, infertility in females
d) Hairy ears
Answer: a
- a) Correct: Classic Down’s features.
- b) Klinefelter’s.
- c) Turner’s.
- d) Y-linked trait.
Q155. Turner’s syndrome is caused by:
a) XXY condition
b) XO condition
c) Trisomy 21
d) Extra Y chromosome
Answer: b
- b) Correct: Turner’s = XO (monosomy of X).
Q156. Individuals with Turner’s syndrome are:
a) Male with 47 chromosomes
b) Female with 45 chromosomes
c) Male with 46 chromosomes
d) Female with 47 chromosomes
Answer: b
- b) Correct: Turner’s = female, 45 chromosomes (XO).
Q157. Turner’s syndrome is characterized by:
a) Tall stature and gynecomastia
b) Short stature, webbed neck, infertility
c) Flat face and upward eye slant
d) Overproduction of RBCs
Answer: b
- b) Correct: Turner’s = short female, webbed neck, underdeveloped ovaries.
Q158. Klinefelter’s syndrome is caused by:
a) Trisomy 21
b) XO condition
c) XXY condition
d) Extra autosome
Answer: c
- c) Correct: Klinefelter’s = 47 chromosomes, XXY.
Q159. Individuals with Klinefelter’s syndrome are:
a) Male with 46 chromosomes
b) Male with 47 chromosomes (XXY)
c) Female with XO
d) Female with XXX
Answer: b
- b) Correct: Male, 47, XXY.
Q160. Symptoms of Klinefelter’s syndrome include:
a) Short stature, webbed neck
b) Mental retardation, flat face
c) Tall stature, gynecomastia, sterile male
d) Increased body hair, aggressive nature
Answer: c
- c) Correct: Klinefelter’s = tall, sterile males, breast development.
Q161. Which of the following is a numerical chromosomal disorder?
a) Deletion
b) Translocation
c) Trisomy 21
d) Inversion
Answer: c
- c) Correct: Trisomy 21 = numerical abnormality.
- a, b, d) Structural changes.
Q162. Which of the following is a structural chromosomal disorder?
a) Down’s syndrome
b) Turner’s syndrome
c) Cri-du-chat syndrome
d) Klinefelter’s syndrome
Answer: c
- c) Correct: Cri-du-chat = deletion of chromosome 5 short arm.
Q163. Monosomy means:
a) Loss of an entire set of chromosomes
b) Loss of a single chromosome
c) Addition of a chromosome
d) Duplication of a segment
Answer: b
- b) Correct: Monosomy = missing one chromosome from a pair (2n–1).
Q164. Which of the following is an example of monosomy?
a) Turner’s syndrome
b) Down’s syndrome
c) Klinefelter’s syndrome
d) Edwards syndrome
Answer: a
- a) Correct: Turner’s = XO → monosomy of sex chromosome.
Q165. Trisomy means:
a) Loss of one chromosome
b) Gain of one chromosome
c) Loss of entire set
d) Polyploidy
Answer: b
- b) Correct: Trisomy = extra copy of a chromosome (2n+1).
Q166. Which of the following is NOT a trisomy disorder?
a) Down’s syndrome
b) Edwards syndrome
c) Patau syndrome
d) Turner’s syndrome
Answer: d
- d) Correct: Turner’s = monosomy, not trisomy.
Q167. Edwards syndrome is caused by:
a) Trisomy 21
b) Trisomy 18
c) Trisomy 13
d) XO
Answer: b
- b) Correct: Edwards = trisomy 18.
Q168. Patau syndrome is caused by:
a) Trisomy 21
b) Trisomy 18
c) Trisomy 13
d) XXY
Answer: c
- c) Correct: Patau = trisomy 13.
Q169. Which chromosomal disorder is characterized by cat-like crying in infants?
a) Down’s syndrome
b) Cri-du-chat syndrome
c) Edwards syndrome
d) Turner’s syndrome
Answer: b
- b) Correct: Cri-du-chat = deletion on chromosome 5 → cat-like cry.
Q170. Polyploidy is common in:
a) Animals
b) Humans
c) Plants
d) Bacteria
Answer: c
- c) Correct: Polyploidy (3n, 4n, etc.) common in plants, rare in animals.
Q171. Which of the following individuals will be phenotypically male?
a) XXY
b) XO
c) XXX
d) Trisomy 21
Answer: a
- a) Correct: XXY (Klinefelter’s) = phenotypically male.
Q172. The chromosomal number of a Down’s syndrome individual is:
a) 45
b) 46
c) 47
d) 48
Answer: c
- c) Correct: Down’s = 47 chromosomes.
Q173. The common feature of all chromosomal disorders is:
a) They are inherited in Mendelian manner
b) They arise during gametogenesis
c) They are curable with medicines
d) They affect only autosomes
Answer: b
- b) Correct: Chromosomal disorders arise due to errors during gamete formation (nondisjunction).
Q174. Nondisjunction during meiosis leads to:
a) Point mutation
b) Aneuploidy
c) Polyploidy only
d) Structural changes only
Answer: b
- b) Correct: Nondisjunction → aneuploidy (monosomy/trisomy).
Q175. Which chromosomal disorder is characterized by webbed neck and underdeveloped ovaries?
a) Down’s syndrome
b) Turner’s syndrome
c) Klinefelter’s syndrome
d) Edwards syndrome
Answer: b
- b) Correct: Turner’s = XO → webbed neck, female infertility.
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