Answer :
Final answer:
The enzyme that cleaves long, double-stranded RNA into short pieces of double-stranded RNA is Dicer, which generates siRNAs and miRNAs involved in gene regulation.
Explanation:
The enzyme that cleaves long, double-stranded RNA into short pieces of double-stranded RNA is Dicer. Dicer is an endoribonuclease that processes long double-stranded RNAs (dsRNA) and short hairpin pre-microRNAs (miRNA) into short interfering RNAs (siRNA) or microRNAs (miRNAs). These resulting RNA fragments typically measure between 19-25 nucleotides for miRNAs and 21-23 nucleotides for siRNAs, each with two unpaired nucleotides at their 3' end. The siRNAs produced are perfectly complementary to their target mRNAs, resulting in endoribonuclease cleavage of the mRNA, thereby inhibiting translation.
On the other hand, miRNAs may not be perfectly complementary, often binding to the 3' untranslated region of the target mRNA, potentially inhibiting translation or causing mRNA degradation if the match is sufficiently close.
