Single-stranded version of a gene; recipe for a protein.

Single-stranded version of a gene; recipe for a protein.

• A. mRNA
• B. Ribosome
• C. DNA polymerase III
• D. Telomere

Answer: (A)

The idea being tested is how genetic information is turned into a protein through an RNA copy that can be used to build the protein. The single-stranded copy of a gene that carries the instructions to make a protein is messenger RNA, or mRNA. During transcription, the DNA sequence is copied into an mRNA transcript, which then exits the nucleus and is read by the ribosome to assemble the protein. The “recipe” metaphor fits because mRNA contains the codons that specify the order of amino acids in the protein. Ribosomes are the machines that translate the message in mRNA into a protein, not the copy of the gene itself. DNA polymerase III is involved in copying DNA during replication, not in producing an RNA template for translation. Telomeres are the repetitive ends of chromosomes that protect genetic info, not the information-carrying copy used to make a protein. So the single-stranded, information-carrying copy used to direct protein synthesis is mRNA.

The idea being tested is how genetic information is turned into a protein through an RNA copy that can be used to build the protein. The single-stranded copy of a gene that carries the instructions to make a protein is messenger RNA, or mRNA. During transcription, the DNA sequence is copied into an mRNA transcript, which then exits the nucleus and is read by the ribosome to assemble the protein. The “recipe” metaphor fits because mRNA contains the codons that specify the order of amino acids in the protein.

Ribosomes are the machines that translate the message in mRNA into a protein, not the copy of the gene itself. DNA polymerase III is involved in copying DNA during replication, not in producing an RNA template for translation. Telomeres are the repetitive ends of chromosomes that protect genetic info, not the information-carrying copy used to make a protein.

So the single-stranded, information-carrying copy used to direct protein synthesis is mRNA.