Biology STAAR (State of Texas Assessments of Academic Readiness) Practice Test

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Study for the Biology STAAR Test. Improve your skills with flashcards and multiple choice questions, each question is accompanied by hints and explanations. Prepare for success!

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Which type of RNA acts as a messenger?

tRNA
rRNA
mRNA
siRNA

The correct answer is: mRNA

mRNA, or messenger RNA, plays a crucial role in the process of gene expression. It is synthesized during transcription, where a specific segment of DNA is copied into RNA. This mRNA molecule carries genetic information from the DNA in the nucleus to the ribosomes, the cellular machinery responsible for protein synthesis. Once in the ribosome, mRNA serves as a template for the assembly of amino acids into proteins, with each sequence of three nucleotides (codon) corresponding to a specific amino acid. This function underscores mRNA's key role as a messenger between the genetic code stored in DNA and the production of proteins, which are essential for various cellular functions and structures. Other types of RNA have different roles; for instance, tRNA (transfer RNA) is responsible for bringing the appropriate amino acids to the ribosome, rRNA (ribosomal RNA) forms the core of the ribosome's structure and aids in protein synthesis, and siRNA (small interfering RNA) is involved in the regulation of gene expression by degrading mRNA.