CSMLS Molecular Diagnostics 2

Question 1

What is the function of restriction endonucleases in molecular biology?

Accepted Answer

To cleave double-stranded DNA at specific palindromic recognition sequences

Answer

Restriction endonucleases recognize short specific palindromic sequences and cut both DNA strands at or near those sites, producing defined fragments used in cloning, RFLP analysis, and restriction mapping.

Question 2

16S rRNA gene sequencing is considered the gold standard for bacterial species identification because:

Accepted Answer

The gene contains conserved primer-binding regions flanking variable species-identifying regions

Answer

The 16S rRNA gene has conserved regions that allow universal primers to bind across all bacteria, flanking variable regions whose sequences differ enough between species to provide definitive identification.

Question 3

In Southern blotting, why is the gel treated with alkali after electrophoresis?

Accepted Answer

To denature double-stranded DNA into single strands before transfer

Answer

Alkali denaturation converts the double-stranded DNA in the gel into single strands; single-stranded DNA is then transferred to a membrane where it can hybridize with a complementary labeled probe.

Question 4

Which next-generation sequencing (NGS) platform uses fluorescently labeled reversible terminator nucleotides incorporated one base at a time?

Accepted Answer

Illumina sequencing by synthesis

Answer

Illumina's sequencing-by-synthesis uses fluorescently labeled, reversible terminator dNTPs; after each base is incorporated and imaged, the terminator is cleaved to allow incorporation of the next nucleotide.

Question 5

Restriction fragment length polymorphism (RFLP) analysis detects genetic variation by:

Accepted Answer

Identifying sequence changes that create or abolish restriction enzyme recognition sites

Answer

RFLP detects sequence polymorphisms where a nucleotide change creates or destroys a restriction site, producing fragments of different sizes that are separated and visualized by electrophoresis.

CSMLS - Canadian Society for Medical Laboratory Science Practice Test

CSMLS - Canadian Society for Medical Laboratory Science Practice Test

CSMLS Molecular Diagnostics 2