Molecular Diagnostic Techniques in Medical Microbiology: Quizzes and Practice Questions

Question 1

In the polymerase chain reaction (PCR), which step occurs first, and what is its primary purpose?

Accepted Answer

Denaturation of DNA to separate the strands

Answer

Annealing of primers to DNA sequences

Answer

Extension of primers by DNA polymerase

Answer

Ligation of DNA fragments into a plasmid

Question 2

What is the main purpose of PCR (Polymerase Chain Reaction)?

Accepted Answer

Amplify specific DNA sequences

Answer

Detect specific antigens

Answer

Identify antibodies in a sample

Answer

Sequence DNA fragments

Question 3

What is the primary application of Sanger sequencing?

Accepted Answer

Detecting genetic mutations

Answer

Diagnosing infectious agents

Answer

Monitoring gene expression levels

Answer

Quantifying microbial load

Question 4

Which enzyme plays a crucial role in DNA amplification during PCR?

Accepted Answer

DNA polymerase

Answer

RNA polymerase

Answer

Reverse transcriptase

Answer

DNA ligase

Question 5

Which of the following techniques is NOT classified as a serological assay?

Accepted Answer

PCR (Polymerase Chain Reaction)

Answer

ELISA (Enzyme-Linked Immunosorbent Assay)

Answer

Western blot

Answer

Immunofluorescence assay

Question 6

Which step is not included in the polymerase chain reaction (PCR)?

Accepted Answer

Ligation

Answer

Denaturation

Answer

Annealing

Answer

Extension

Question 7

What is the primary purpose of a DNA sequencing machine?

Accepted Answer

To determine the nucleotide sequence of a DNA molecule

Answer

To amplify a specific DNA sequence

Answer

To detect the presence of a particular microorganism

Answer

To quantify the amount of DNA in a sample

Question 8

Which serological assay is commonly used for HIV antibody detection?

Accepted Answer

ELISA

Answer

Agglutination test

Answer

Precipitation test

Answer

RIA

Question 9

Which of the following is not a potential limitation of molecular diagnostic techniques?

Accepted Answer

Straightforward interpretation

Answer

High cost

Answer

Specialized equipment requirements

Answer

Potential false positives

Question 10

What is the primary function of primers in PCR?

Accepted Answer

Annealing to specific regions of the DNA template

Answer

Initiating DNA synthesis

Answer

Denaturing the DNA template

Answer

Extending the newly synthesized DNA strand

Question 11

What is the main purpose of gel electrophoresis in molecular diagnostics?

Accepted Answer

Separating DNA fragments based on size

Answer

Amplifying DNA fragments

Answer

Detecting the presence of specific DNA sequences

Answer

Quantifying the amount of DNA in a sample

Question 12

How do qualitative and quantitative molecular diagnostic tests differ?

Accepted Answer

Qualitative tests detect the presence or absence of a target sequence, while quantitative tests measure its quantity.

Answer

Quantitative tests detect the presence or absence of a target sequence, while qualitative tests measure its quantity.

Answer

There is no difference between qualitative and quantitative molecular diagnostic tests.

Answer

Qualitative tests measure the quantity of a target sequence, while quantitative tests detect its presence or absence.

Question 13

What are the key advantages of using molecular diagnostic techniques in outbreak investigations?

Accepted Answer

Faster and more accurate pathogen identification

Accepted Answer

High sensitivity and specificity for reliable results

Accepted Answer

Tracking pathogen evolution and transmission patterns

Answer

Cost-effectiveness and wide availability

Question 14

Which component is NOT present in a PCR reaction?

Accepted Answer

RNA polymerase

Answer

DNA template

Answer

Primers

Answer

DNA polymerase

Question 15

Which serological assay is primarily used for HIV antibody detection?

Accepted Answer

ELISA

Answer

Western blot

Answer

Immunofluorescence assay

Answer

Complement fixation test

Question 16

What are the steps involved in PCR amplification?

Accepted Answer

Denaturation, annealing, extension

Answer

Precipitation, centrifugation, hybridization

Answer

Electrophoresis, ligation, restriction digestion

Answer

Chromatography, spectroscopy, mass spectrometry

Question 17

How does real-time PCR differ from end-point PCR?

Accepted Answer

Real-time PCR monitors amplification during the reaction, while end-point PCR does not

Answer

End-point PCR is more sensitive than real-time PCR

Answer

Both real-time and end-point PCR utilize the same reagents

Answer

There is no distinction between real-time and end-point PCR

Question 18

Which of the following is NOT a step in the polymerase chain reaction (PCR)?

Accepted Answer

Gel filtration

Answer

Annealing

Answer

Extension

Answer

Denaturation

Question 19

Which DNA polymerase is specifically designed to withstand the high temperatures required for PCR amplification?

Accepted Answer

Taq polymerase

Answer

RNA polymerase

Answer

Primase

Answer

Helicase

Question 20

What is the primary objective of DNA sequencing?

Accepted Answer

Determining the precise order of nucleotides in a DNA molecule

Answer

Detecting mutations

Answer

Amplifying DNA fragments

Question 21

Which of the following methods is widely used for DNA sequencing?

Accepted Answer

Sanger sequencing

Answer

Flow cytometry

Answer

Western blotting

Answer

Southern blotting

Question 22

What is the fundamental principle behind serological assays?

Accepted Answer

Detection of antibodies or antigens present in a specimen

Answer

Visualization of chromosomes

Answer

Separation of proteins

Answer

Amplification of nucleic acids

Question 23

What is a key advantage of employing molecular diagnostic techniques in medical microbiology?

Accepted Answer

Enhanced sensitivity and specificity in microbial identification and diagnosis

Answer

Lower cost and faster turnaround time

Answer

Ease of use and lack of technical expertise required

Question 24

Which of the following types of microorganisms can be detected using molecular diagnostic techniques?

Accepted Answer

Bacteria, viruses, fungi, and parasites

Answer

Only bacteria

Answer

Only viruses

Answer

Only bacteria and viruses

Question 25

What is a potential challenge in implementing molecular diagnostic techniques in resource-limited settings?

Accepted Answer

High cost and requirement for specialized equipment and expertise

Answer

Difficulty in obtaining samples

Answer

Low sensitivity and specificity

Question 26

Which of the following factors should be carefully considered when selecting a molecular diagnostic technique for a particular application?

Accepted Answer

Cost, sensitivity, specificity, turnaround time, and availability of expertise

Answer

Only sensitivity and specificity

Answer

Only cost and turnaround time