Ch 13 Transcription Flashcards
Which of these types of RNA becomes structural and functional components of the ribosome subunits?
rRNA
A gene’s promoter is usually found _____ of the transcription initiation site.
upstream
Once transcription has been initiated, RNA polymerase adds nucleotides to the 3’ end of the growing RNA molecule until it transcribes a _____.
terminator
Which type of RNA molecule is found in eukaryotes but not bacteria?
pre-mRNA
The primary products of transcription in eukaryotic cells are large precursor molecules called pre-mRNA that are modified extensively before becoming mRNA.
A transcription unit encodes all of these, EXCEPT
-promoters
-RNA-coding regions.
-terminators
Correct: -tRNA molecules.
What would be the likely result of moving the –10 and –35 consensus sequences to a new location?
Transcription would initiate, but the start site would be different.
Which of these nucleotide sequences might be found in an RNA molecule that forms a secondary structure of a stem with no loop?
5’CAUAGGCAAUAUUGCCUAUG-3’
This sequence has complementary sequences that are contiguous, and it would form a hairpin that has a stem but no loop.
A mutation that destroys the function of a promoter would affect which stage of transcription?
initiation
If the promoter that best matches the consensus sequence shown serves as the strongest promoter, then which sequence would serve as the strongest promoter?
G C C A T A A A
This sequence matches the consensus perfectly.
-G C A A T A G A
-G G T A T C T A
-G C G A T T C G
An RNA molecule has the percentages of bases shown: A = 30%, U = 23%, C = 20%, and G = 27%. What is the percentage of A in the template strand of DNA that encodes this RNA, assuming that the template strand contains no introns?
23%
If a gene were 60 nucleotides long, where in the transcription unit would a mutation most likely affect whether or not the gene was transcribed?
+35
Positive numbers indicate downstream, which is where the transcription unit moves.
Promoters are essential for transcription in eukaryotes. Which of these elements are matched appropriately?
C: Initiator element
C is the initiator element. It can vary in its sequencing, but it will always be the first nucleotide recognized for transcription before the unit progresses downstream.
In the diagram, which strand is the b gene transcribed from?
top strand
When is the sigma factor typically released from the holoenzyme?
-upon the movement of RNA polymerase beyond the promoter
The sigma factor binds the promoter for sequencing, so once it is passed, the sigma factor is no longer needed.
Which of these statements is true concerning elongation in eukaryotes?
Most of the transcription factors are left at the promoter to reinitiate transcription with other polymerases.
Which of these statements is NOT true regarding transcription in bacteria, archaea, and eukaryotic cells?
The RNA polymerase of archaea is more like the RNA polymerase of bacteria.
Archaea, like bacteria, have a single RNA polymerase, but this enzyme is most similar to the RNA polymerases of eukaryotes.
Sheila is experimenting with possible gene dysfunction based on its sequencing in bacterial cells. In her experiment, she creates a transcription marker that signals for an addition of five nucleotides to the RNA strand. The marker only activates when a guanine is paired with uracil. Assuming the probability of guanine pairing with uracil is 10%, what would be the total nucleotide count of the RNA molecule? Assume that the initial strand is 100 nucleotides long and that the base composition of guanine is 20%
110 nucleotide
Which process in eukaryotes is shown in the electron micrograph?
transcription
Ten sequences from the upstream region of a group of genes are shown. What is the best expression of the consensus sequence derived from these actual sequences?
Incorrect: G Y C T N C A R
Incorrect: G C C T N C A Y
Correct: G N C T R C A Y
incorrect: G N C T R C A Y
Selene is targeting RNA molecules for a function test. She introduces a molecule that signals a cascade that causes the lysosome to degrade the nucleus. Which of these molecules would not be immediately affected by the action of the lysosome?
tRNA
Transfer RNA are primarily housed in the cytoplasm and would not be readily affected by the action of the lysosome.
If the sequence of an RNA molecule is 5′-GGCAUCGACG-3′, what is the sequence of the nontemplate strand of DNA?
5′-GGCATCGACG-3′
Shown are the steps that comprise the initiation of RNA synthesis. What is the correct sequence of these steps?
I. creation of the first bonds between rNTPs
II. formation of a transcription bubble
III. escape of the transcription apparatus from the promoter
IV. promoter recognition
IV, II, I, III
