Why does an mRNA molecule need to be made during transcription?

• A. Because mRNA is required to transport amino acids to the ribosome.
• B. Because mRNA directly replicates DNA for cell division.
• C. Because mRNA is the enzyme that catalyzes the formation of peptide bonds.
• D. Because mRNA serves as a temporary copy of genetic information that can be used to synthesize proteins.

Answer: (D)

Verified step by step guidance

1. Understand the role of mRNA in the central dogma of molecular biology: DNA contains the genetic instructions for making proteins, but it cannot leave the nucleus. mRNA acts as a temporary copy of these instructions that can travel to the ribosome in the cytoplasm.
2. Recognize that transcription is the process where the DNA sequence of a gene is copied into mRNA. This ensures that the genetic information is preserved and can be used for protein synthesis without risking damage to the original DNA.
3. Learn that mRNA carries the genetic code in the form of codons, which are sequences of three nucleotides. Each codon corresponds to a specific amino acid or a stop signal during translation.
4. Understand that mRNA is not involved in transporting amino acids to the ribosome (this is the role of tRNA), nor does it replicate DNA for cell division (this is the role of DNA replication). Additionally, mRNA is not an enzyme; it does not catalyze peptide bond formation (this is the role of the ribosome and rRNA).
5. Conclude that mRNA serves as a temporary copy of genetic information, allowing the cell to synthesize proteins based on the instructions encoded in DNA. This is why mRNA is essential during transcription.