MDT - Exam 1 Practice UPDATED
QUESTIONS AND CORRECT ANSWERS
What are the three components of a DNA nucleotide? - CORRECT
ANSWER Deoxyribose sugar, phosphate group, and a nitrogenous base (A, T, C, or G)
What type of bond links nucleotides within a DNA strand? - CORRECT
ANSWER Phosphodiester bonds between the 3' hydroxyl and 5' phosphate
What does 5' to 3' directionality mean? - CORRECT ANSWER DNA strands have
polarity based on carbon numbering of the sugar; synthesis occurs from 5' to 3'
How are the two DNA strands oriented relative to each other? - CORRECT
ANSWER Anti-parallel
What bonds hold complementary DNA strands together? - CORRECT
ANSWER Hydrogen bonds between complementary bases
What is the purpose of PCR? - CORRECT ANSWER To amplify a specific DNA
sequence
How many PCR cycles are typically performed? - CORRECT ANSWER 20-50 cycles
(30-35 ideal)
What happens during the denaturation step of PCR? - CORRECT ANSWER Double-
stranded DNA separates into single strands
What is the temperature range for denaturation? - CORRECT ANSWER 90-96°C
What happens during the annealing step of PCR? - CORRECT ANSWER Primers bind
to complementary sequences on the template DNA
, What determines annealing temperature? - CORRECT ANSWER Primer melting
temperature (Tm)
What happens during the extension step of PCR? - CORRECT ANSWER DNA
polymerase synthesizes new DNA strands
What is the temperature range for extension? - CORRECT ANSWER 68-75°C
What enzyme is most commonly used in PCR? - CORRECT ANSWER Taq DNA
polymerase
What types of targets can molecular tests detect? - CORRECT ANSWER Pathogen
genes or host genes
What organisms can molecular diagnostics detect? - CORRECT ANSWER Bacteria,
viruses, fungi, parasites
Why can molecular tests be repeated for infectious disease? - CORRECT
ANSWER Infections can recur and tests can assess cure or clearance
What does viral load testing measure? - CORRECT ANSWER Quantity of viral
nucleic acid (e.g., Hepatitis C)
How can antibiotic resistance genes spread between bacteria? - CORRECT
ANSWER Via plasmids
Which genes indicate resistance to clindamycin or vancomycin? - CORRECT
ANSWER ermA/ermC and vanA
QUESTIONS AND CORRECT ANSWERS
What are the three components of a DNA nucleotide? - CORRECT
ANSWER Deoxyribose sugar, phosphate group, and a nitrogenous base (A, T, C, or G)
What type of bond links nucleotides within a DNA strand? - CORRECT
ANSWER Phosphodiester bonds between the 3' hydroxyl and 5' phosphate
What does 5' to 3' directionality mean? - CORRECT ANSWER DNA strands have
polarity based on carbon numbering of the sugar; synthesis occurs from 5' to 3'
How are the two DNA strands oriented relative to each other? - CORRECT
ANSWER Anti-parallel
What bonds hold complementary DNA strands together? - CORRECT
ANSWER Hydrogen bonds between complementary bases
What is the purpose of PCR? - CORRECT ANSWER To amplify a specific DNA
sequence
How many PCR cycles are typically performed? - CORRECT ANSWER 20-50 cycles
(30-35 ideal)
What happens during the denaturation step of PCR? - CORRECT ANSWER Double-
stranded DNA separates into single strands
What is the temperature range for denaturation? - CORRECT ANSWER 90-96°C
What happens during the annealing step of PCR? - CORRECT ANSWER Primers bind
to complementary sequences on the template DNA
, What determines annealing temperature? - CORRECT ANSWER Primer melting
temperature (Tm)
What happens during the extension step of PCR? - CORRECT ANSWER DNA
polymerase synthesizes new DNA strands
What is the temperature range for extension? - CORRECT ANSWER 68-75°C
What enzyme is most commonly used in PCR? - CORRECT ANSWER Taq DNA
polymerase
What types of targets can molecular tests detect? - CORRECT ANSWER Pathogen
genes or host genes
What organisms can molecular diagnostics detect? - CORRECT ANSWER Bacteria,
viruses, fungi, parasites
Why can molecular tests be repeated for infectious disease? - CORRECT
ANSWER Infections can recur and tests can assess cure or clearance
What does viral load testing measure? - CORRECT ANSWER Quantity of viral
nucleic acid (e.g., Hepatitis C)
How can antibiotic resistance genes spread between bacteria? - CORRECT
ANSWER Via plasmids
Which genes indicate resistance to clindamycin or vancomycin? - CORRECT
ANSWER ermA/ermC and vanA
