Question : RNA polymerase is thought to be disengaged from the : 2134104

16) RNA polymerase is thought to be disengaged from the DNA template by

A. the Xrn2 exonuclease

B. cleavage and polyadenylation specific-factor (CPSF)

C. poly(A) polymerase

D. the spliceosome

17) Nuclear pre-mRNA introns are

A. self-splicing

B. removed by an endoribonuclease

C. removed by the spliceosome

D. require an external guanosine nucleotide as a cofactor.

18) RNA splicing of nuclear pre-mRNA involves removal of

A. introns from a primary RNA transcript by a series of two transesterification reactions.

B. exons from a primary RNA transcript by a series of two transesterification reactions.

C. introns from a primary RNA transcript by a series of polyadenylation reactions.

D. exons from a primary RNA transcript by a series of polyadenylation reactions.

19) The spliceosome is composed of

A. U1, U2, U3, U4, and U5 snRNPs

B. five different U-rich snRNAs and more than 200 proteins

C. small ribosomal RNAs and associated proteins

D. more than 200 proteins

20) Which snRNPs are thought to contribute to the catalysis of pre-mRNA splicing?

A. U1 and U2 snRNPs

B. U2 and U4 snRNPs

C. U5 and U6 snRNPs

D. U2 and U6 snRNPs