Question

A single strand of nucleic acid tagged with a radioactive molecule is called

• A. vector
• B. selectable marker
• C. plasmid
• D. probe

Answer 1

The correct option is D probe

A single-stranded nucleic acid tagged with a radioactive molecule is called a probe. Probes are 15-30 base long radioactive labeled oligonucleotides (RNA or DNA) used to detect complementary nucleotide sequence, e.g. used for disease diagnosis, etc.
A vector is a DNA molecule used as a vehicle to artificially carry foreign genetic material into another cell, where it can be replicated and/or expressed (e.g.- plasmid, cosmid, Lambda phages). A vector containing foreign DNA is termed recombinant DNA.
A selectable marker is a gene introduced into a cell, especially a bacterium or to cells in culture, that confers a trait suitable for artificial selection.