DBT LBC – EXAM TEST QUESTIONS AND CORRECT
ANSWESR (VERIFIED ANSWERS) PLUS RATIONALES
2025/2026 Q&A |INSTANT DOWNLOAD PDF
1. Which of the following is a component of a DNA molecule?
A. Amino acid
B. Nucleotide
C. Glucose
D. Fatty acid
*Correct answer: B. Nucleotide – DNA is made up of nucleotides, which consist of
a sugar, phosphate group, and nitrogenous base.
2. What is the primary function of the polymerase chain reaction (PCR)?
A. Sequence DNA
B. Amplify DNA
C. Transcribe RNA
D. Translate protein
*Correct answer: B. Amplify DNA – PCR is used to produce millions of copies of a
specific DNA sequence.
3. Which enzyme is responsible for unwinding the DNA double helix during
replication?
A. Ligase
B. Helicase
C. Polymerase
D. Primase
*Correct answer: B. Helicase – Helicase separates the two strands of DNA,
creating the replication fork.
,4. In molecular diagnostics, which technique is commonly used to detect a
specific DNA sequence?
A. ELISA
B. Western blot
C. Southern blot
D. Northern blot
*Correct answer: C. Southern blot – Southern blotting allows detection of specific
DNA sequences in a sample.
5. Which type of RNA carries the genetic code from DNA to ribosomes?
A. rRNA
B. tRNA
C. mRNA
D. snRNA
*Correct answer: C. mRNA – Messenger RNA carries the coding information for
protein synthesis from the nucleus to the cytoplasm.
6. During electrophoresis, DNA fragments move toward the:
A. Negative electrode
B. Positive electrode
C. Neutral electrode
D. DNA does not move
*Correct answer: B. Positive electrode – DNA is negatively charged due to
phosphate groups and migrates toward the positive electrode.
7. Which staining method is commonly used to visualize DNA in agarose gels?
A. Hematoxylin
B. Ethidium bromide
C. Crystal violet
D. Gram stain
*Correct answer: B. Ethidium bromide – It intercalates between DNA bases and
fluoresces under UV light.
8. Which of the following is an application of real-time PCR (qPCR)?
A. Detecting protein expression
, B. Quantifying DNA or RNA
C. Measuring cell viability
D. Observing cell morphology
*Correct answer: B. Quantifying DNA or RNA – qPCR allows real-time
measurement of nucleic acid amplification.
9. In LBC (Liquid-Based Cytology), the primary purpose is to:
A. Preserve tissue morphology
B. Concentrate and clean cytological samples
C. Extract DNA only
D. Culture cells
*Correct answer: B. Concentrate and clean cytological samples – LBC improves
sample quality and reduces obscuring elements.
10. Which fixative is commonly used in LBC samples?
A. Formalin
B. Alcohol-based solution
C. Bouin’s solution
D. Glutaraldehyde
*Correct answer: B. Alcohol-based solution – Alcohol preserves cellular
morphology and prevents degradation.
11. The principle of hybrid capture in molecular diagnostics involves:
A. Antigen-antibody binding
B. Nucleic acid hybridization
C. Enzyme activity detection
D. Electrophoresis separation
*Correct answer: B. Nucleic acid hybridization – It detects specific DNA or RNA
sequences by forming complementary hybrids.
12. Which of the following is a characteristic feature of malignant cells in
cytology?
A. Small, uniform nuclei
B. High nuclear-cytoplasmic ratio
C. Regular chromatin pattern
ANSWESR (VERIFIED ANSWERS) PLUS RATIONALES
2025/2026 Q&A |INSTANT DOWNLOAD PDF
1. Which of the following is a component of a DNA molecule?
A. Amino acid
B. Nucleotide
C. Glucose
D. Fatty acid
*Correct answer: B. Nucleotide – DNA is made up of nucleotides, which consist of
a sugar, phosphate group, and nitrogenous base.
2. What is the primary function of the polymerase chain reaction (PCR)?
A. Sequence DNA
B. Amplify DNA
C. Transcribe RNA
D. Translate protein
*Correct answer: B. Amplify DNA – PCR is used to produce millions of copies of a
specific DNA sequence.
3. Which enzyme is responsible for unwinding the DNA double helix during
replication?
A. Ligase
B. Helicase
C. Polymerase
D. Primase
*Correct answer: B. Helicase – Helicase separates the two strands of DNA,
creating the replication fork.
,4. In molecular diagnostics, which technique is commonly used to detect a
specific DNA sequence?
A. ELISA
B. Western blot
C. Southern blot
D. Northern blot
*Correct answer: C. Southern blot – Southern blotting allows detection of specific
DNA sequences in a sample.
5. Which type of RNA carries the genetic code from DNA to ribosomes?
A. rRNA
B. tRNA
C. mRNA
D. snRNA
*Correct answer: C. mRNA – Messenger RNA carries the coding information for
protein synthesis from the nucleus to the cytoplasm.
6. During electrophoresis, DNA fragments move toward the:
A. Negative electrode
B. Positive electrode
C. Neutral electrode
D. DNA does not move
*Correct answer: B. Positive electrode – DNA is negatively charged due to
phosphate groups and migrates toward the positive electrode.
7. Which staining method is commonly used to visualize DNA in agarose gels?
A. Hematoxylin
B. Ethidium bromide
C. Crystal violet
D. Gram stain
*Correct answer: B. Ethidium bromide – It intercalates between DNA bases and
fluoresces under UV light.
8. Which of the following is an application of real-time PCR (qPCR)?
A. Detecting protein expression
, B. Quantifying DNA or RNA
C. Measuring cell viability
D. Observing cell morphology
*Correct answer: B. Quantifying DNA or RNA – qPCR allows real-time
measurement of nucleic acid amplification.
9. In LBC (Liquid-Based Cytology), the primary purpose is to:
A. Preserve tissue morphology
B. Concentrate and clean cytological samples
C. Extract DNA only
D. Culture cells
*Correct answer: B. Concentrate and clean cytological samples – LBC improves
sample quality and reduces obscuring elements.
10. Which fixative is commonly used in LBC samples?
A. Formalin
B. Alcohol-based solution
C. Bouin’s solution
D. Glutaraldehyde
*Correct answer: B. Alcohol-based solution – Alcohol preserves cellular
morphology and prevents degradation.
11. The principle of hybrid capture in molecular diagnostics involves:
A. Antigen-antibody binding
B. Nucleic acid hybridization
C. Enzyme activity detection
D. Electrophoresis separation
*Correct answer: B. Nucleic acid hybridization – It detects specific DNA or RNA
sequences by forming complementary hybrids.
12. Which of the following is a characteristic feature of malignant cells in
cytology?
A. Small, uniform nuclei
B. High nuclear-cytoplasmic ratio
C. Regular chromatin pattern
