Final answer:
During splicing, introns are removed, and exons are joined together to create functional RNA. This is carried out by spliceosomes, which ensure the accuracy of the process. Proper splicing is crucial for producing functional proteins.
Step-by-step explanation:
To create a functional RNA, the pre-mRNA undergoes a process known as splicing. During the splicing process, the introns are removed and the remaining exons are connected to each other.
The importance of accurate splicing cannot be overstated. If the process errs by even a single nucleotide, the reading frame of the rejoined exons would shift, leading to the production of a dysfunctional protein. This precision is achieved by intricate molecular machinery known as spliceosomes, which are complexes made up of proteins and RNA molecules, including small nuclear RNAs (snRNAs). Spliceosomes are responsible for recognizing the specific nucleotide sequences at the 5' and 3' ends of an intron to ensure its exact removal and the correct joining of exons.
During splicing, spliceosomes bind to introns and excise them out of the pre-mRNA, while the exons are spliced together. This process not only removes non-coding regions but can also lead to different variations of proteins being produced through alternative splicing. This results in a diversity of proteins with varying structures and functions that are critical for the biological complexity of an organism.