Multiple ChoiceTranscription in eukaryotes requires which of the following molecules in addition to RNA polymerase?4834views6rank
Multiple ChoiceWhich of the following properties is NOT shared by RNA polymerase and DNA polymerase?2454views18rank
Multiple ChoiceOne strand of a DNA molecule has the following sequence: 3′-AGTACAAACTATCCACCGTC-5′. In order for that strand to be transcribed, there would have to be a specific recognition sequence, called a(n) __________, to the left of the DNA sequence indicated. 991views
Textbook QuestionIn eukaryotic cells, transcription cannot begin until a. the two DNA strands have completely separated and exposed the promoter. b. several transcription factors have bound to the promoter. c. the 5′ caps are removed from the mRNA. d. the DNA introns are removed from the template.1826views1rank
Textbook QuestionThe RNA polymerase enzyme binds to , initiating transcription. a. amino acids; b. tRNA; c. the promoter sequence; d. the ribosome1193views
Textbook QuestionIn a particular bacterial species, temperature-sensitive conditional mutations cause expression of a wild-type phenotype at one growth temperature and a mutant phenotype at another—typically higher—temperature. Imagine that when a bacterial cell carrying such a mutation is shifted from low to high growth temperatures, RNA polymerases in the process of elongation complete transcription normally, but no new transcripts can be started. The mutation in this strain most likely affects: a. the terminator sequence b. the start codon c. sigma d. one of the polypeptides of the core RNA polymerase649views
Textbook QuestionIn a particular bacterial species, temperature-sensitive conditional mutations cause expression of a wild-type phenotype at one growth temperature and a mutant phenotype at another—typically higher—temperature. Imagine that when a bacterial cell carrying such a mutation is shifted from low to high growth temperatures, RNA polymerases in the process of elongation complete transcription normally, but no new transcripts can be started. The mutation in this strain most likely affects: a. the terminator sequence b. the start codon c. sigma d. one of the polypeptides of the core RNA polymerase538views
Textbook QuestionThe nucleotide shown here is called cordycepin triphosphate. It is a natural product of a fungus that is used in traditional medicines. If cordycepin triphosphate is added to a cell-free transcription reaction, the nucleotide is added onto the growing RNA chain but then no more nucleotides can be added. Examine the structure of cordycepin and explain why it ends transcription. 576views
Textbook QuestionEating even a single death cap mushroom (Amanita phalloides) can be fatal due to a compound called αα-amanitin, a toxin that inhibits transcription.What would you predict to be the immediate outcome of adding αα-amanitin to a cell? a. reduced DNA synthesis b. reduced production of one or more types of RNA c. reduced binding of tRNAs to anticodons d. reduced rate of translocation of ribosomes translating mRNA971views
Textbook QuestionEating even a single death cap mushroom (Amanita phalloides) can be fatal due to a compound called αα-amanitin, a toxin that inhibits transcription.What would you predict to be the immediate outcome of adding αα-amanitin to a cell? a. reduced DNA synthesis b. reduced production of one or more types of RNA c. reduced binding of tRNAs to anticodons d. reduced rate of translocation of ribosomes translating mRNA525views
Textbook Questionα-Amanitin inhibits transcription by binding inside an RNA polymerase to a region other than the active site that catalyzes addition of a nucleotide to the RNA chain. Based on the model of RNA polymerase shown in Figure 17.3, predict how the toxin might function to inhibit transcription. 867views
Textbook QuestionToxins like αα-amanitin are used for research in much the same way as null mutants (Chapter 16)—to disrupt a process and see what happens when it no longer works. Researchers examined the ability of αα-amanitin to inhibit different RNA polymerases. They purified RNA polymerases I, II, and III from rat liver, incubated the enzymes with different concentrations of αα-amanitin, and then tested their activity. The results of this experiment are shown here. These findings suggest that cells treated with αα-amanitin will have a reduced level of: a. tRNAs b. rRNAs c. snRNAs d. mRNAs588views
Textbook QuestionIf you wanted to use αα-amanitin to shut down 95 percent of transcription by RNA polymerase II, roughly what concentration of αα-amanitin would you use? Note that the scale on the x-axis of the graph in Question 13 is logarithmic rather than linear, so that each tick mark shows a tenfold higher concentration.665views
Textbook QuestionEach of the following statements about protein synthesis is false. Correct each to make a true statement.c. The enzyme RNA polymerase builds a strand of transfer RNA, whose codons are complementary to DNA's triplets.211views
Multiple ChoiceDuring which stage of transcription do the following processes take place?1. RNA polymerase binds to the promoter.2. The RNA transcript is released.3. The RNA transcript extended.117views1rank
Multiple ChoiceWhich of the following is the correct transcript of mRNA for the following DNA template?DNA Template: 3'-ATGAAGCCGAGTCAT-5'.99views1comments
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