The spliceosome is composed of

The spliceosome is composed of

• A. DNA polymerases
• B. small nuclear ribonucleoproteins (snRNPs)
• C. RNA polymerases
• D. ribosomes

Answer: (B)

The spliceosome is a ribonucleoprotein complex that carries out RNA splicing. Its core components are small nuclear ribonucleoproteins (snRNPs), each made of a small nuclear RNA (snRNA) bound to proteins. The major snRNPs—U1, U2, U4, U5, and U6—recognize splice sites and come together on pre-mRNA to catalyze the two transesterification reactions that remove introns and fuse exons. This RNA-protein combination is what defines the spliceosome, setting it apart from other cellular machines: DNA polymerases build DNA, RNA polymerases transcribe RNA, and ribosomes translate mRNA into protein.

The spliceosome is a ribonucleoprotein complex that carries out RNA splicing. Its core components are small nuclear ribonucleoproteins (snRNPs), each made of a small nuclear RNA (snRNA) bound to proteins. The major snRNPs—U1, U2, U4, U5, and U6—recognize splice sites and come together on pre-mRNA to catalyze the two transesterification reactions that remove introns and fuse exons. This RNA-protein combination is what defines the spliceosome, setting it apart from other cellular machines: DNA polymerases build DNA, RNA polymerases transcribe RNA, and ribosomes translate mRNA into protein.