Deck 8: Nucleic Acid-Based Analytic Methods for Microbial Identification and Characterization

Question 1

The enzyme that is commonly used for primer extensions in the PCR method works best at what temperature?

A) 25º C
B) 56º C
C) 72º C
D) 94º C

Answer 1

C
Taq polymerase is the enzyme commonly used for primer extensions, which occurs at 72° C.

Question 2

The probe in the hybridization assay can be described as:

A) originating from the unknown organism to be detected or identified.
B) a reporter molecule that chemically forms a complex with the single-stranded probe deoxyribonucleic acid (DNA).
C) originating from an organism of known identity with a known sequence.
D) the enzyme needed to elongate the strand.

Answer 2

C
The probe in a hybridization assay is made from a known organism that is the same as the organism being sought in the assay.

Question 3

The enzyme that has the ability to synthesize DNA from ribonucleic acid (RNA)is called:

A) DNA polymerase.
B) RNAse.
C) helicase.
D) reverse transcriptase.

Answer 3

D
The reverse transcriptase enzyme has the ability to direct the synthesis of DNA from the viral RNA template.

Question 4

Determining the exact nucleotide sequence of a gene or gene fragment obtained from an unknown organism is based on which of the following methods?

A) Hybridization
B) Sequencing
C) Amplification (PCR)
D) Genotypic

Question 5

Gen-Probe Mycobacterium tuberculosis direct test uses which type of nucleic acid amplification test?

A) Nucleic acid sequence-based amplification (NASBA)
B) Transcription-mediated amplification (TMA)
C) Reverse transcriptase polymerase chain reaction (RT-PCR)
D) Standard displacement amplification (SDA)

Question 6

Nucleic acid sequencing methods are based on:

A) the ability of two nucleic acid strands that have complementary base sequences to bond specifically with each other and form a double-stranded molecule.
B) detecting phenotypic traits not detectable by conventional strategies.
C) the principles of complementary nucleic acid hybridization with those of nucleic acid replication.
D) determining the exact nucleotide sequence of a gene or gene fragment obtained from an organism.

Question 7

Complementary nucleic acid hybridization, which is coupled with nucleic acid replication and applied repeatedly through numerous cycles, is based on which of the following methods?

A) Hybridization
B) Sequencing
C) Amplification (PCR)
D) Genotypic

Question 8

Hybridization methods are based on:

A) the ability of two nucleic acid strands that have complementary base sequences to bond specifically with each other and form a double-stranded molecule.
B) detecting phenotypic traits not detectable by conventional strategies.
C) the principles of complementary nucleic acid hybridization with those of nucleic acid replication that are repeatedly applied through numerous cycles.
D) determining the exact nucleotide sequence of a gene or gene fragment obtained from an organism.

Question 9

The optimal way to detect PCR amplicons is to use which stain?

A) Methylene blue
B) Malachite green
C) Bromothymol blue
D) Ethidium bromide

Question 10

Which enzyme recognizes a specific nucleotide sequence (~4-8 nucleotides in length)and catalyzes the digestion of the nucleic acid at that site, causing a break in the DNA strand?

A) Ligase
B) Gyrase
C) Helicase
D) Endonuclease

Question 11

The target in the hybridization assay can be described as:

A) originating from the unknown organism to be detected or identified.
B) a reporter molecule that chemically forms a complex with the single-stranded probe DNA.
C) originating from an organism of known identity.
D) an enzyme that adds nucleotides during the replication process.

Question 12

An organism whose genetic makeup is 50% C-G bonds would have a(n)_________ melting temperature (Tm), compared with an organism with 20% C-G bonds.

A) higher
B) lower
C) equal
D) similar

Question 13

Which type of hybridization method would be the optimal choice to use to detect a lesion infected with a particular virus?

A) Southern
B) In situ
C) Peptide nucleic acid
D) Sandwich

Question 14

The ability of two nucleic acid strands, a probe and a target, which have complementary base sequences that specifically bond with each other and form a double-stranded molecule, drives which of the following methods?

A) Hybridization
B) Sequencing
C) Amplification (PCR)
D) Genotypic

Question 15

Target nucleic acid amplification (polymerase chain reaction [PCR])methods are based on:

A) the ability of two nucleic acid strands that have complementary base sequences to bond specifically with each other and form a double-stranded molecule.
B) detecting phenotypic traits not detectable by conventional strategies.
C) the principles of complementary nucleic acid hybridization with those of nucleic acid replication that are repeatedly applied through numerous cycles.
D) determining the exact nucleotide sequence of a gene or gene fragment obtained from an organism.