Match the following properties with the correct polymerase require a primer lack

ID: 55388 • Letter: M

Question

Match the following properties with the correct polymerase

require a primer

lack 3' 5' proofreading exonuclease activity

use nucleoside triphosphates as substrates

produce an antiparallel complement strand to the template

synthesize nucleic acids in the direction 3' 5'

evolutionary well-conserved

RNA polymerase

Both enzymes

DNA polymerase

Neither enzyme

3.5 points

QUESTION 2

RNA polymerase from E. coli (core enzyme alone) has all of the following properties except that ____________________.

is required for the synthesis of mRNA, rRNA, and tRNA in E. coli.

requires all four ribonucleoside triphosphates and a DNA template.

recognizes specific start signals in DNA.

it can extend an RNA chain and initiate a new chain.

produces an RNA polymer that begins with a 5'-triphosphate.

3.5 points

QUESTION 3

The Sigma factor by itself has a very low affinity to promoter sites. Predict the effect of a mutation enabling to bind to the -10 region in absence of the other RNA polymerase subunits.

The increase in ’s affinity to promoter DNA will increase the efficiency of specific transcription at promoter sites.

The increase in ’s affinity to promoter DNA will inhibit promoter clearance by RNA polymerase and decrease transcription rate.

The binding of to the -10 region of bacterial promoter stabilizes the single-stranded configuration of DNA and will lead to chromosome unraveling.

The mutant will competitively inhibit the binding of RNA polymerase holoenzyme, preventing, at least partially, the specific initiation of RNA polymerization at promoter sites.

3.5 points

QUESTION 4

The sigma factor of E. coli RNA polymerase ____________________.

combines with the core enzyme to confer specific binding to a promoter.

is inseparable from the core enzyme.

associates with the promoter before binding core enzyme.

is required for termination of an RNA chain.

will catalyze synthesis of RNA from both DNA template strands in the absence of the core enzyme.

3.5 points

QUESTION 5

Compare the mechanism of transcription and DNA replication.

In which process, one daughter strand (the leading strand) is elongated continuously while the other daughter strand (the lagging strand) is formed as a series of discontinuous Okazaki fragments?

Which process is driven forward by hydrolysis of pyrophosphate (PPi), which is then further hydrolyzed to inorganic phosphate (Pi), from each incoming nucleoside triphosphate?

Which process is driven forward by hydrolysis of ATP during the polymerization of each incoming nucleotide?

In which process divalent metal ions (typically magnesium or manganese) play an important role?

Both

DNA replication

Neither

Transcription

3.5 points

QUESTION 6

Compare the need for a primer in DNA replication vs. transcription.

Which process (processes) requires (require) an RNA primer in vivoand either an RNA or DNA primer in vitro?

Which process doesn't require a primer neither in vivo nor in vitro ?

Which process requires an RNA primer in vivo but no primer in vitro?

Which process requires an RNA primer in vivo but a DNA primer invitro?

Both

Transcription

Neither

DNA replication

3.5 points

QUESTION 7

Compare the start sites for DNA replication vs. transcription.

Start Site: Which process (processes) starts (start) in a promoter region?

Start Site: Which process (processes) starts (start) in an origin of replication?

Start Site: Which process (processes) has (have) one start site per genome in bacteria but many start sites in eukaryotes?

Start Site: Which process (processes) has (have) many start sites per genome in prokaryotes and eukaryotes alike?

Neither

Both

DNA replication

Transcription

3.5 points

QUESTION 8

The yellow-highlighted sequences encompass the binding site for the TATA binding protein.

The yellow-highlighted sequences encompass a bacterial promoter.

The yellow-highlighted sequences encompass a rho-independent termination sequence.

The yellow-highlighted sequences encompass a eukaryotic promoter.

3.5 points

QUESTION 9

During the initiation phase of transcription, the factor acts catalytically. In other words,

the factor catalyzes the polymerization of the first few tens of nucleotides.

the factor catalyzes the melting of the DNA strands.

the factor is released from the initiation complex following the polymerization of a few tens of nucleotides and can then asist another RNA pol core in another round of initiation; thus, several core enzymes are served by one factor

the factor supplies the energy needed for the initiation phase of transcription.

3.5 points

QUESTION 10

Gene expression in E. coli is controlled mainly at the transcription initiation stage.

True False

3.5 points

QUESTION 11

If two E. coli genes, tesA and tesB, have identical promoter sequences except in the 10 region, where the tesA sequence is TAATAT and the tesB sequence is TGTCGA, which gene do you expect to be more efficiently transcribed

The tesA 10 element conforms more closely with the consensus sequence, which fits very well to the notion that it is a run-of-the-mill promoter with "Goldilocks" properties: not too strong not to weak. In contrast, the tesB 10 sequence deviates from the consensus sequence, and its higher GC content will increase its stability indicating that it will be stronger than the tesA promoter resulting in more transcripts being produced as compared to the tesA promoters.

The tesB 10 sequence deviates more from the consensus sequence, and its higher GC content will be more difficult to melt. Assuming these genes use similar transcription initiation modes, more tesA mRNA is expected relative to tesB.

The tesA 10 sequence deviates more from the consensus sequence, and its higher A=T content makes it much less stable. Assuming these genes use similar transcription initiation modes, more tesB mRNA is expected relative to tesA.

The 10 element's sequence is not very well conserved and while clearly important, it is less important than the well conserved -35 sequence. Therefore, it is not predicted that there will be huge differences in the strength of the two promoters.

3.5 points

QUESTION 12

Match the following structural and functional attributes of a -independent transcription termination signal with the corresponding sequences on the DNA template strand.

causing the RNA polymerase to pause

directs the formation of hairpin in RNA

promotes the dissociation of the RNA-DNA hybrid

oligo(U) stretch in RNA

A-rich region

GC-rich palindromic region

3.5 points

QUESTION 13

The aim of the experiment was to understand the function of the enzyme -gal.

The aim of the experiment was to identify new antibacterial interventions by interfering with transcription.

The aim of the experiment was to identify what is the consensus sequence of the -10 box and what is the consensus spacer length.

The aim of the experiment was to test the effects on promoter activity of lac promoter variants that were made to progressively look more and more like the canonical bacterial promoter in their -10 box sequence and consensus spacer length.

3.5 points

QUESTION 14

One of the benefits of transcription and mRNA (as opposed to having the translation machinery works directly on the DNA) is signal amplification. The term here means that

the "message" encoded in one gene is "broadcasted" many times - first in the form of many copies of mRNA transcribed from the gene and then as many copies of protein molecules translated from the mRNA.

mistakes in the DNA (that is mutations) can be amplified to create a real problem, which will lead to reduction in fitness and fewer offspring.

signals conveyed to the cell from the outside can get to the nucleus.

only the amplitude of gene expression needs to be regulated, but not its frequency.

- A. B. C. D.

require a primer