Biology STAAR Practice Test 2025 – Comprehensive All-in-One Guide to Mastering the State of Texas Readiness Exam!

The correct option highlights that mRNA plays a crucial role in both transcription and translation. During transcription, a segment of DNA is used as a template to synthesize a complementary strand of mRNA. This process occurs in the nucleus of the cell, where RNA polymerase enzyme facilitates the assembly of RNA nucleotides based on the DNA template. The newly formed mRNA strand then undergoes processing, including splicing, capping, and polyadenylation, before it exits the nucleus.

Once the mRNA is in the cytoplasm, it serves as the template for translation, the stage where proteins are synthesized. During translation, ribosomes read the sequence of codons in the mRNA and assemble the corresponding amino acids into a polypeptide chain, effectively translating the genetic code into a functional protein.

Understanding that mRNA is essential for both transcription and translation clarifies its integral role in the central dogma of molecular biology, which describes the flow of genetic information from DNA to RNA to protein. This multifaceted involvement of mRNA is why the correct answer encompasses both processes.