Molecular Diagnostic Techniques

What holds two single strands of DNA together in a double helix?

• a. 2′ carbon of deoxyribose attached to a hydroxyl group
• b. Hydrogen bonds between A and T and C and G
• c. Ribose 3′ carbon hydroxyl attached to ribose 5′ carbon phosphate
• d. Phosphorylation of nitrogen bases

What is the complement to the following DNA sequence? 5′-GATCGATTCG-3′

• b. 3′-CGAATCGATC-5′
• c. 3′-GCTTAGCTAG-5′
• d. 3′-GATCGATTCG-5′
• a. 3′-CTAGCTAAGC-5′

How are DNA and RNA different?

• a. Only RNA contains uracil.
• b. Only DNA contains cytosine.
• c. DNA is usually single stranded.
• d. DNA is less stable than RNA.

What is the function of restriction endonucleases?

• a. They splice short pieces of DNA together.
• b. They cleave DNA at specific sites.
• c. They make RNA copies of DNA.
• d. They make DNA copies from RNA.

What is the purpose of somatic hypermutation in genes that code for antibodies?

• a. To increase diversity of the immunoglobulin repertoire
• b. To prevent further antibody formation
• c. To switch antibodies from IgM to IgG
• d. To prevent further VDJ recombination

What characteristic distinguishes restriction enzymes from one another?

• a. Diverse binding and cutting sites
• b. Ability to quickly digest DNA
• c. RNA degradation capability
• d. Ability of one enzyme to recognize several different binding sites

Which of the following is used in a Southern blot procedure?

• a. A ligase joins two adjacent probes.
• b. Radiolabeled nucleotides are used to synthesize DNA.
• c. DNA is cleaved by enzymes and electrophoresed.
• d. Many probes are placed on a small piece of glass.

Which best describes the PCR?

• a. Two probes are joined by a ligating enzyme.
• b. RNA copies of the original DNA are made.
• c. Extender probes are used to create a visible product.
• d. Primers are used to make multiple DNA copies.

What takes place during in situ hybridization?

• a. RNA polymerase copies messenger RNA.
• b. Hybridization takes place in solution.
• c. Nucleic acid probes react with intact cells in tissues.
• d. Probes are protected from degradation if hybridized.

What determines the specificity for PCR?

• a. Nucleotide mix ratios and concentrations
• b. Mono- and divalent cation concentrations
• c. Primers and their annealing temperature
• d. DNA polymerase