Chap.16

25 July 2022
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question
The segments of DNA where transcription begins have a binding site for RNA polymerase. The segments are known as _________. Select one: a. sigma b. the holoenzyme c. promoters d. initiation factors
answer
The answer is: promoters.
question
How are RNA hairpin turns related to termination? a. Release factors bind to sites on the hairpin turn, causing release of the ENA transcript. b. the turns are formed from complementary bas pairing and cause separation the RNA transcript and RNA polymerase c. The hairpin turn prevents more nucleoside triphosphates from entering the active site of the enzymes, effectively shutting off the process of polymerization. d. A three-base repeat signals a stop sequence, and the RNA transcript is released
answer
The answer is: the turns are formed from complementary bas pairing and cause separation the RNA transcript and RNA polymerase.
question
Put the following events of elongation in prokaryotic translation in chronological order. 1. binding of mRNA with small ribosomal subuint 2. recognition of initiation codon 3. complementary base pairing between initiation codon and anticodon of initiatior tRNA 4. base pairing of the mRNA codon following the initiator codon with its complementary tRNA Select one: a. 1,2,3,4,5 b. 2,1,4,3,5 c. 1,2,3,5,4 d. 5,4,3,2,1
answer
The answer is: 1,2,3,5,4.
question
A primary transcript in the nucleus of a eukaryotic cell is _________the functional mRNA, while a primary transcript in a prokaryotic cell is _________ the functional mRNA. Select one: a. the same size as; larger than b. larger than; the same size as c. larger than; smaller than d. the same size as; the same size as
answer
The answer is: larger than; the same size as.
question
Which of the following processes is central to the initiation of transcription? Select one: a. binding of DNA polymerase to the promoter region b. formation of a DNA primer c. binding of sigma to the promoter region d. formation of a phosphodiester bond in the elongating RNA strand
answer
The answer is: binding of sigma to the promoter region. The start codon is the same for prokaryotes and eukaryotes.
question
What is the start codon? Select one: a. an anticodon b. a robozyme c. AUG d. CGC
answer
The answer is: AUG.
question
(x)Which of the following occurs in prokaryotes, but not eukaryote? Select one: a. concurrent transcription and translation b. post-transcriptional splicing c. translation in the absence of a ribosome d. gene regulation
answer
The answer is: concurrent transcription and translation.
question
Which of the following is not one of the steps in initiation of translation? Select one: a. binding of the large ribosomal subunit to the small ribosomal subunit b. formation of a polypeptide bond c. binding of tRNA carrying formyl methionine to the start codong and small ribosomal subunit d. recognition and binding of mRNA by the small ribosomal subunit
answer
The answer is: formation of a polypeptide bond.In
question
(x)What molecule is responsible for the catalytic activity in the spliceosomes that are involved in removal of introns? Select one: a. Proteins of the spliceosome b. Ribozymes c. Autocatalysis by introns d. RNA polymerase
answer
The answer is: Ribozymes.
question
RNA polymerase needs a subunit to initiate transcription that is not needed for transcript elongation. What is the subunit? Select one: a. Rho b. Sigma c. Mg2+ d. The holoenzyme
answer
The answer is: Sigma.
question
How does termination of translation take place? Select one: a. energy depletion causes termination b. the ribosome reaches the end of the mRNA molecule c. hairpin turns of mRNA force the ribosome off the molecule d. stop codons with no corresponding tRNAs are read
answer
The answer is: stop codons with no corresponding tRNAs are read.
question
Which molecule or reaction supplies the energy for polymerization of nucleotides in the process of transcription? Select one: a. the interaction between RNA polymerase and the promoter b. ATP only c. the energy released when hydrogen bonds are broken as the DNA molecule is unwound d. the phosphate bonds in the nucleotide triphosphates that serve as substrates
answer
The answer is: the phosphate bonds in the nucleotide triphosphates that serve as substrates.
question
Ribosomes can attach to prokaryotic messenger RNA________. Select one: a. Once the primary transcript has been released from RNA polymerase. b. Before transcription is complete c. Once replication is complete d. once post-transcriptional modification is complete.
answer
The answer is: Before transcription is complete.
question
Put the following events of transcription in chronological order. 1. sigma binds to the promoter region 2. the double helix of DNA is unwound, breaking hydrogen bonds between complementary strands. 3. sigma binds to RNA polymerase 4. sigma is released transcription begins Select one: a. 3,1,2,5,4 b. 3,2,1,4,5 c. 2,3,4,5 d. 2,3,1,4,5
answer
The answer is: 3,1,2,5,4.