Q.1 What is the main focus of cytogenetics?
Study of enzyme functions
Study of chromosomes and their structure
Study of protein synthesis
Study of RNA transcription
Explanation - Cytogenetics is the branch of genetics that studies the structure and function of chromosomes.
Correct answer is: Study of chromosomes and their structure
Q.2 Which staining technique is commonly used to visualize chromosomes in cytogenetics?
Gram staining
Giemsa staining
H&E staining
Silver staining
Explanation - Giemsa staining is widely used to visualize chromosomes and produce characteristic banding patterns.
Correct answer is: Giemsa staining
Q.3 What is the typical human chromosome number in a normal somatic cell?
23
46
44
22
Explanation - Humans have 46 chromosomes in somatic cells, arranged in 23 pairs.
Correct answer is: 46
Q.4 What is a karyotype?
A diagram showing an individual's DNA sequence
A test for enzyme activity
A complete set of chromosomes arranged in a standard format
A protein structure analysis
Explanation - A karyotype displays all chromosomes of an individual, organized by size, shape, and number.
Correct answer is: A complete set of chromosomes arranged in a standard format
Q.5 Which of the following chromosomal abnormalities involves an extra chromosome 21?
Turner syndrome
Klinefelter syndrome
Down syndrome
Cri-du-chat syndrome
Explanation - Down syndrome, also called trisomy 21, results from an extra copy of chromosome 21.
Correct answer is: Down syndrome
Q.6 Which chromosomal abnormality is characterized by a single X chromosome in females?
Klinefelter syndrome
Turner syndrome
Down syndrome
Patau syndrome
Explanation - Turner syndrome occurs in females with only one X chromosome (45,X).
Correct answer is: Turner syndrome
Q.7 Which technique allows detection of specific DNA sequences on chromosomes using fluorescent probes?
FISH (Fluorescence In Situ Hybridization)
PCR
Western blot
ELISA
Explanation - FISH uses fluorescent probes to detect and localize specific DNA sequences on chromosomes.
Correct answer is: FISH (Fluorescence In Situ Hybridization)
Q.8 Which term describes a change in the number of chromosomes?
Translocation
Aneuploidy
Inversion
Deletion
Explanation - Aneuploidy is the presence of an abnormal number of chromosomes in a cell.
Correct answer is: Aneuploidy
Q.9 What is the chromosomal pattern in Klinefelter syndrome?
45,X
47,XXY
47,XYY
46,XY
Explanation - Klinefelter syndrome occurs in males with an extra X chromosome, resulting in 47,XXY karyotype.
Correct answer is: 47,XXY
Q.10 Which structural chromosomal abnormality results in part of one chromosome being attached to another chromosome?
Duplication
Translocation
Inversion
Deletion
Explanation - Translocation is the transfer of a chromosome segment to a nonhomologous chromosome.
Correct answer is: Translocation
Q.11 Which cytogenetic technique is used to visualize chromosomal banding patterns?
Karyotyping
ELISA
Flow cytometry
SDS-PAGE
Explanation - Karyotyping allows visualization of chromosomes and their banding patterns for diagnosis of chromosomal disorders.
Correct answer is: Karyotyping
Q.12 Which syndrome is associated with trisomy 18?
Patau syndrome
Edwards syndrome
Down syndrome
Turner syndrome
Explanation - Edwards syndrome is caused by trisomy 18 and results in severe developmental abnormalities.
Correct answer is: Edwards syndrome
Q.13 Which chromosomal abnormality involves loss of a segment of a chromosome?
Inversion
Deletion
Duplication
Translocation
Explanation - Deletion occurs when a segment of a chromosome is missing, leading to loss of genetic material.
Correct answer is: Deletion
Q.14 Which cytogenetic term describes a reversed segment of a chromosome?
Inversion
Translocation
Duplication
Deletion
Explanation - Inversion occurs when a chromosome segment breaks off, flips, and reinserts, reversing the gene order.
Correct answer is: Inversion
Q.15 Which type of chromosomal abnormality does Down syndrome represent?
Numerical abnormality
Structural abnormality
Point mutation
Insertion
Explanation - Down syndrome is caused by an extra chromosome (trisomy 21), making it a numerical chromosomal abnormality.
Correct answer is: Numerical abnormality
Q.16 Which chromosomal abnormality involves duplication of a chromosome segment?
Deletion
Duplication
Inversion
Translocation
Explanation - Duplication occurs when a chromosome segment is copied and inserted into the same or another chromosome.
Correct answer is: Duplication
Q.17 Which cytogenetic disorder is characterized by severe intellectual disability and the cry of a cat-like sound in infancy?
Cri-du-chat syndrome
Angelman syndrome
Down syndrome
Turner syndrome
Explanation - Cri-du-chat syndrome results from deletion on chromosome 5p and is characterized by cat-like crying in infants.
Correct answer is: Cri-du-chat syndrome
Q.18 Which abnormality is seen in 47,XYY males?
Turner syndrome
Klinefelter syndrome
Jacob's syndrome
Down syndrome
Explanation - Jacob's syndrome involves an extra Y chromosome in males, resulting in 47,XYY karyotype.
Correct answer is: Jacob's syndrome
Q.19 Which technique provides a high-resolution analysis of chromosomal abnormalities at the DNA level?
Array CGH
Karyotyping
Southern blot
ELISA
Explanation - Array Comparative Genomic Hybridization (aCGH) detects copy number variations and small chromosomal abnormalities at high resolution.
Correct answer is: Array CGH
Q.20 Which phase of the cell cycle are chromosomes most easily visualized for karyotyping?
G1 phase
S phase
Metaphase
G2 phase
Explanation - Chromosomes are most condensed and visible during metaphase, making it ideal for karyotyping.
Correct answer is: Metaphase
Q.21 Which cytogenetic abnormality involves two chromosome breaks with the ends rejoining in reverse orientation?
Deletion
Duplication
Inversion
Translocation
Explanation - Inversion occurs when a chromosome segment breaks at two points and reinserts in reverse orientation.
Correct answer is: Inversion
Q.22 Which chromosomal disorder is associated with trisomy 13?
Patau syndrome
Edwards syndrome
Down syndrome
Turner syndrome
Explanation - Patau syndrome is caused by trisomy 13 and leads to severe developmental defects.
Correct answer is: Patau syndrome
Q.23 Which term refers to the complete set of chromosomes in a species or individual?
Genome
Exome
Karyotype
Proteome
Explanation - The genome is the full set of genetic material in a species or individual, including all chromosomes.
Correct answer is: Genome
Q.24 Which chromosomal abnormality is most commonly detected prenatally by amniocentesis?
Numerical abnormalities like trisomy 21
Point mutations
Inversions
Single gene defects
Explanation - Amniocentesis allows prenatal detection of chromosomal abnormalities, especially numerical changes like trisomy 21.
Correct answer is: Numerical abnormalities like trisomy 21
Q.25 Which cytogenetic technique can detect microdeletions that are not visible in a standard karyotype?
FISH
Gram staining
H&E staining
SDS-PAGE
Explanation - FISH uses fluorescent probes to detect microdeletions or duplications that are too small for standard karyotyping.
Correct answer is: FISH