What is the cap and tail and what are their functions?

The cap and tail refer to the modifications made to the ends of eukaryotic mRNA molecules. The 5' cap, consisting of a modified guanine nucleotide, protects the mRNA from degradation, aids in ribosome binding during translation, and facilitates nuclear export. The polyadenylated tail (the "tail") is a stretch of adenine nucleotides added to the 3' end, which also protects the mRNA from degradation and enhances its stability and translation efficiency. Together, they play critical roles in the stability, processing, and translation of mRNA.