Question

Which of the following best describes siRNA?

1) a short double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA
2) a single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns
3) a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor
4) a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits
5) a molecule, known as Dicer, that can degrade other mRNA sequences

Answer 1

Option 1 accurately describes siRNA as a short double-stranded RNA that plays a key role in RNA interference by complementing and inactivating a sequence of mRNA, leading to gene silencing.

Step-by-step explanation:

This process is a part of RNA interference (RNAi) technology, where siRNA plays a crucial role in gene silencing. siRNA, or small interfering RNA, is produced when cells encounter double-stranded RNAs that are typically foreign, such as viral RNA genomes. An enzyme called DICER cleaves these dsRNAs into short fragments known as siRNAs. These siRNAs then associate with the RISC (RNA-induced silencing complex) proteins.

The antisense strand of siRNA within the siRNA-RISC complex then binds to the complementary regions of any mRNA that matches the siRNA sequence. This binding leads to the cleavage and degradation of the mRNA, effectively silencing the gene from which the mRNA was transcribed, thereby preventing the production of the encoded protein.