Which component is crucial for the protection of mRNA from degradation?

The poly-A tail is crucial for the protection of mRNA from degradation because it enhances the stability of the mRNA molecule. The addition of a series of adenine nucleotides to the 3’ end of the mRNA transcript creates a buffer zone that prevents the enzyme-mediated degradation of the mRNA. This modification not only protects mRNA from exonucleases, which are enzymes that degrade RNA from the ends, but also plays a critical role in the regulation of mRNA stability, export from the nucleus, and translation efficiency in the cytoplasm.

In contrast, introns and exons refer to the non-coding and coding regions of a gene, respectively, and are involved in the splicing process during mRNA maturation rather than directly protecting mRNA from degradation. Ribosomal RNA, while essential for the formation of ribosomes and protein synthesis, does not play a role in mRNA stability and degradation.