The U1 splice donor site is critical for positioning of the U1snRNP for appropriate splicing. What site/region(s) participates directly in the phosphoester bond exchange that forms the lariat leading to the correct excision of the intronic segment? Options:   the branch point adenosine   the poly A stretch within the intron (high conservation ~80%)   U2AF binding site (GU) at the 3' intron/exon junction   a and b only   a, b and c

A bacterial species has a hypothetical sigma promoter that has the following sequence: TTGGCA - 18 bases - TATAAT What change in the level of transcription would there be if the sequence was mutated to: TTCGCA -18 bases -TATAAT O The mutation would bind the promoter to the consensus and produce normal levels of transcription O The mutation would inhibit the promoter thereby inhibiting transcription The mutation would move the promoter away from consensus and reduce the level of transcription O No change the consensus TATAAT sequence in the same. D00 F3 F4 F5 F6 F7 F8 F9 % & 5 6 7 8 9 %24

TFIID TFIIA TFIIH TBP TFIIB TFIIF TFIIE

The FIRST transesterification reaction of splicing requires… Group of answer choices The 2’ hydroxyl on the 5’ splice site The 2’ hydroxyl on the 3’ splice site The 2’ hydroxyl on the branch point A All of the above   The addition of a poly(A) tail requires... Group of answer choices snRNPs to hybridize to the mRNA Poly A signal AAUAAA A polymer of T’s in the DNA template The TATA box   In eukaryotes, a drug that inhibits RNA polymerase III will first affect the transcription of… Group of answer choices rRNA mRNA tRNA Poly(A) tail   A bacterial promoter has the transcription start site at position: Group of answer choices -35 +20 +1 -10

The siRNA and miRNA pathways share many similarities and also have some differences. Which of the following is true about these two noncoding RNA classes in regulating gene expression? O Both of them utilize the internally generated RNAS as sources to produce the short regulatory RNAS O Both of them need Dicer to process the long RNAS into short double-strnaded RNAS Both of them required perfect match between the short noncoding RNAS to the MRNAS Both of them end up with complete degradation of the target mRNAs

A novel, RNA-containing splicing factor is purified on the basis of its physical interaction with a previously known subunit of the spliceosome. You sequence the RNA within the new factor, and identify a region that is perfectly complementary to a stretch of the RNA from the previously known subunit with which it interacts. You suspect that the interaction between the new factor and the subunit is mediated by hybridization between these complementary RNA sequences, but would like to be sure. How could you test this experimentally?

Why do promoter mutations cluster at positions −10and −35 as shown in Figure 11-11? Which protein-DNAinteraction is disrupted by these mutations?

In the absence of cladosporin, explain the initiation steps in the synthesis of lysyl-tRNA synthetase enzyme or protein in the bacterial cell, with the involvement of all initiation factors, each site in the ribosome, any important conserved sequence, subunits of ribosomes, initiation codon, charged tRNA containing what amino acid, whether it requires ATP or GTP

GACA CAAT box A site P site E site DREASAARE III III III III III factors and RNA pol to bind to in order to activate gene expression. Accepts charged tRNA molecules whose anticodon complements the codons of mRNA. Holds a nascent elongating polypeptide before final release. Unique sequence found in bacteria between TATAAT and START. 5 upstream consensus motif that is easily melted for transcription purposes in prokaryotes.

Many promoter regions contain CAAT boxes containing consensus sequences CAAT or CCAAT approximately 70 to 80 bases upstream from the transcription start site. How might one determine the influence of CAAT boxes on the transcription rate of a given gene?