Question

What role do miRNA play in controlling DNA expression?

1) By binding to messenger RNA (mRNA) and preventing its translation into protein
2) By directly binding to DNA and inhibiting transcription
3) By promoting the degradation of mRNA molecules
4) By enhancing the activity of DNA polymerase

Answer 1

MiRNAs control gene expression by binding to mRNA with the help of RISC, inhibiting translation and promoting mRNA degradation, thus regulating protein synthesis.

Step-by-step explanation:

The role of microRNAs (miRNAs) in controlling DNA expression is primarily through the post-transcriptional regulation of gene expression. MiRNAs are short RNA molecules that function by binding to the 3' untranslated regions (UTRs) of messenger RNA (mRNA) molecules. They do this with the assistance of a ribonucleoprotein complex called the RNA-induced silencing complex (RISC). This binding can lead to the inhibition of translation and the promotion of mRNA degradation, thus reducing the production of proteins.

Therefore, the correct answer to the student's question is: 1) By binding to mRNA and preventing its translation into protein, and 3) By promoting the degradation of mRNA molecules.