What is the composition of a spliceosome?

The spliceosome is a complex molecular machine that plays a crucial role in the process of splicing pre-mRNA to remove introns and join exons together. The correct composition of a spliceosome includes small nuclear ribonucleoproteins (snRNPs) along with various other proteins that associate with these snRNPs to form a functional spliceosome.

Each snRNP is a combination of small nuclear RNA (snRNA) and specific proteins, and typically, multiple snRNPs work together to recognize splice sites in the pre-mRNA. Additionally, the presence of other proteins is essential for the assembly, stability, and catalysis of the splicing process. This complex structure allows for the precise modification of RNA transcripts, which is vital for gene expression.

Given this understanding, the choice that identifies the spliceosome as consisting of snRNPs and other proteins accurately reflects its composition and functional requirements in the RNA splicing process. Other options do not adequately represent the components and relevant interactions that define a spliceosome's structure and function.