Certified Cytogenetic Technologist (CG)
Exam 20252026[Complete Exam prep
Questions with verified Answers]
100%Correct Answers
1. What is the normal human diploid chromosome number?
A. 22
B. 23
C. 46
D. 48
The human diploid genome contains 46 chromosomes, arranged in 23 pairs,
including 22 autosomal pairs and 1 pair of sex chromosomes.
2. Which phase of mitosis is characterized by the alignment of chromosomes
at the metaphase plate?
A. Prophase
B. Anaphase
C. Metaphase
D. Telophase
During metaphase, chromosomes line up at the metaphase plate, preparing for
separation.
3. Which staining method is used to visualize G-bands on chromosomes?
A. C-banding
B. Q-banding
C. R-banding
D. G-banding
G-banding uses Giemsa stain to produce a characteristic light and dark banding
pattern, allowing chromosome identification.
4. Which chromosome abnormality is characterized by trisomy 21?
A. Turner syndrome
B. Klinefelter syndrome
C. Down syndrome
,D. Patau syndrome
Down syndrome is caused by an extra copy of chromosome 21 (trisomy 21).
5. Which enzyme is responsible for cutting DNA at specific sequences during
molecular cytogenetics?
A. DNA polymerase
B. RNA polymerase
C. Restriction endonuclease
D. Ligase
Restriction enzymes recognize specific DNA sequences and cleave the DNA, a
key tool in molecular cytogenetics.
6. Which technique allows visualization of specific DNA sequences on
chromosomes using fluorescent probes?
A. PCR
B. Western blot
C. Southern blot
D. FISH (Fluorescence In Situ Hybridization)
FISH uses fluorescent-labeled probes to bind complementary DNA sequences on
chromosomes.
7. Which type of chromosomal rearrangement involves a segment of a
chromosome being reversed end to end?
A. Deletion
B. Duplication
C. Inversion
D. Translocation
An inversion occurs when a chromosome segment breaks and reinserts in the
reverse orientation.
8. Which cytogenetic abnormality is common in chronic myeloid leukemia
(CML)?
A. Trisomy 21
B. Philadelphia chromosome (t(9;22))
C. Turner syndrome
D. Edwards syndrome
The Philadelphia chromosome is a reciprocal translocation between
chromosomes 9 and 22, producing the BCR-ABL fusion gene.
, 9. Which specimen type is most commonly used for prenatal cytogenetic
analysis?
A. Peripheral blood
B. Skin biopsy
C. Amniotic fluid
D. Bone marrow
Amniotic fluid contains fetal cells suitable for karyotyping in prenatal testing.
10. Which is the main difference between a metaphase spread and an
interphase nucleus in cytogenetics?
A. DNA sequence
B. Chromosome condensation
C. RNA transcription
D. Cell membrane composition
Metaphase chromosomes are condensed and visible as discrete structures,
while interphase nuclei have uncondensed chromatin.
11. Which of the following is a common cause of mosaicism?
A. Parental consanguinity
B. Environmental toxins
C. Mitotic nondisjunction after fertilization
D. Meiosis I nondisjunction
Mosaicism arises when a post-zygotic error during mitosis produces two or
more genetically distinct cell lines.
12. Which type of chromosome abnormality involves loss of a chromosome
segment?
A. Inversion
B. Translocation
C. Deletion
D. Duplication
A deletion is the loss of a chromosome segment, which can be terminal or
interstitial.
13. Which banding technique specifically highlights centromeric
heterochromatin?
A. G-banding
B. R-banding
C. C-banding
Exam 20252026[Complete Exam prep
Questions with verified Answers]
100%Correct Answers
1. What is the normal human diploid chromosome number?
A. 22
B. 23
C. 46
D. 48
The human diploid genome contains 46 chromosomes, arranged in 23 pairs,
including 22 autosomal pairs and 1 pair of sex chromosomes.
2. Which phase of mitosis is characterized by the alignment of chromosomes
at the metaphase plate?
A. Prophase
B. Anaphase
C. Metaphase
D. Telophase
During metaphase, chromosomes line up at the metaphase plate, preparing for
separation.
3. Which staining method is used to visualize G-bands on chromosomes?
A. C-banding
B. Q-banding
C. R-banding
D. G-banding
G-banding uses Giemsa stain to produce a characteristic light and dark banding
pattern, allowing chromosome identification.
4. Which chromosome abnormality is characterized by trisomy 21?
A. Turner syndrome
B. Klinefelter syndrome
C. Down syndrome
,D. Patau syndrome
Down syndrome is caused by an extra copy of chromosome 21 (trisomy 21).
5. Which enzyme is responsible for cutting DNA at specific sequences during
molecular cytogenetics?
A. DNA polymerase
B. RNA polymerase
C. Restriction endonuclease
D. Ligase
Restriction enzymes recognize specific DNA sequences and cleave the DNA, a
key tool in molecular cytogenetics.
6. Which technique allows visualization of specific DNA sequences on
chromosomes using fluorescent probes?
A. PCR
B. Western blot
C. Southern blot
D. FISH (Fluorescence In Situ Hybridization)
FISH uses fluorescent-labeled probes to bind complementary DNA sequences on
chromosomes.
7. Which type of chromosomal rearrangement involves a segment of a
chromosome being reversed end to end?
A. Deletion
B. Duplication
C. Inversion
D. Translocation
An inversion occurs when a chromosome segment breaks and reinserts in the
reverse orientation.
8. Which cytogenetic abnormality is common in chronic myeloid leukemia
(CML)?
A. Trisomy 21
B. Philadelphia chromosome (t(9;22))
C. Turner syndrome
D. Edwards syndrome
The Philadelphia chromosome is a reciprocal translocation between
chromosomes 9 and 22, producing the BCR-ABL fusion gene.
, 9. Which specimen type is most commonly used for prenatal cytogenetic
analysis?
A. Peripheral blood
B. Skin biopsy
C. Amniotic fluid
D. Bone marrow
Amniotic fluid contains fetal cells suitable for karyotyping in prenatal testing.
10. Which is the main difference between a metaphase spread and an
interphase nucleus in cytogenetics?
A. DNA sequence
B. Chromosome condensation
C. RNA transcription
D. Cell membrane composition
Metaphase chromosomes are condensed and visible as discrete structures,
while interphase nuclei have uncondensed chromatin.
11. Which of the following is a common cause of mosaicism?
A. Parental consanguinity
B. Environmental toxins
C. Mitotic nondisjunction after fertilization
D. Meiosis I nondisjunction
Mosaicism arises when a post-zygotic error during mitosis produces two or
more genetically distinct cell lines.
12. Which type of chromosome abnormality involves loss of a chromosome
segment?
A. Inversion
B. Translocation
C. Deletion
D. Duplication
A deletion is the loss of a chromosome segment, which can be terminal or
interstitial.
13. Which banding technique specifically highlights centromeric
heterochromatin?
A. G-banding
B. R-banding
C. C-banding
