Molecular Diagnostics Flashcards
7 cards from real Medical Laboratory Technician Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Molecular Diagnostics flashcards as text
Which technique is used to amplify specific DNA sequences in molecular diagnostics?
Answer: Polymerase chain reaction (PCR)
PCR (polymerase chain reaction) uses thermal cycling with DNA polymerase to exponentially amplify specific DNA sequences.
What is the purpose of the denaturation step in PCR?
Answer: To separate double-stranded DNA into single strands
Denaturation (typically at 94-98°C) breaks the hydrogen bonds between complementary base pairs, separating double-stranded DNA into single strands so primers can bind.
Which enzyme is essential for the PCR amplification process?
Answer: Taq polymerase
Taq polymerase, derived from Thermus aquaticus, is a heat-stable DNA polymerase that can withstand the high temperatures used in PCR cycling.
In real-time PCR (qPCR), fluorescence is measured to:
Answer: Quantify the amount of target DNA during amplification
In real-time PCR, fluorescent dyes or probes generate a signal proportional to the amount of amplified DNA, allowing quantification during each cycle.
Which molecular technique is used to detect RNA viruses such as HIV or SARS-CoV-2?
Answer: Reverse transcriptase PCR (RT-PCR)
RT-PCR first converts RNA into complementary DNA (cDNA) using reverse transcriptase before PCR amplification, making it suitable for RNA virus detection.
What does a Southern blot technique detect?
Answer: Specific DNA sequences
Southern blotting transfers denatured DNA from a gel to a membrane, where it is hybridized with a labeled probe to detect specific DNA sequences.
Which specimen collection tube is most appropriate for molecular testing of whole blood?
Answer: Lavender top (EDTA)
EDTA (lavender top) tubes are preferred for molecular testing of whole blood because EDTA chelates calcium, preventing DNA degradation and inhibiting nuclease activity.