Question 1

The transcription unit includes three essential regions.What is the proper order of these regions?
a.terminator,RNA coding sequence,promoter
b.RNA coding sequence,promoter,terminator
c.promoter,RNA coding sequence,terminator
d.RNA coding sequence,terminator,promoter
e.promoter,terminator,RNA coding sequence

Accepted Answer

The proper order of essential regions in the transcription unit is promoter, RNA coding sequence, and terminator. The promoter region is necessary for the initiation of transcription, RNA coding sequence contains the information for protein synthesis, and the terminator signals the end of transcription.

Question 2

Which of the following is true of RNA compared to DNA?
a.RNA and DNA use the same bases.
b.RNA has a hydroxyl group on the 2'-carbon atom of its sugar component.
c.Both are primarily double stranded.
d.RNA exists in one form.
e.RNA is more stable than DNA.

Accepted Answer

RNA has a hydroxyl group on the 2'-carbon atom of its sugar component, while DNA has just a hydrogen atom in the same position. This difference makes RNA more chemically reactive than DNA.

Question 3

When RNA is transcribed from a gene,which strand of DNA is used?
a.the template strand
b.the nontemplate strand
c.RNA is transcribed from either strand at random.
d.RNA is transcribed from either strand in a regulated manner.

the t emplate strand

Accepted Answer

During transcription, the RNA polymerase enzyme reads the DNA double helix and uses one of the strands as a template to synthesize a complementary RNA strand. This strand is called the template strand or antisense strand. The other strand, which is not transcribed, is called the nontemplate strand or sense strand. Therefore, the template strand is used to transcribe RNA from a gene.

Question 4

In rho-dependent transcription termination,the rho factor binds to ___________.&#10;a.mRNA&#10;b.DNA near the end of the transcribed region)&#10;c.RNA polymerase&#10;d.sigma subunit

Accepted Answer

The rho factor binds to the mRNA at a specific site called the rut site to facilitate termination of transcription.

Question 5

The bacterial holoenzyme binds to which part of the promoter?
a.-10 consensus sequence
b.-35 consensus sequence
c.-10 and -35 consensus sequence
d.The holoenzyme does not bind to the promoter.

Accepted Answer

The bacterial holoenzyme binds to both the -10 and -35 consensus sequences of the promoter. These consensus sequences are recognized by the sigma factor subunit of the holoenzyme, allowing for efficient binding and initiation of transcription.

Question 6

If an mRNA is hybridized to DNA and we observe loops of noncoding DNA that are not hybridized to DNA,then what might we conclude?
a.The gene and protein are collinear.
b.The gene and protein are not collinear.
c.The loops signify a mutation in that DNA region.
d.No conclusions can be made.

Accepted Answer

If there are loops of noncoding DNA that are not hybridized to DNA, then this would suggest that the gene and protein are not collinear. In other words, there is a section of noncoding DNA that is present in the mRNA but not in the DNA sequence. This could occur due to the inclusion of introns or other regulatory sequences that are transcribed but not translated into protein.

Question 7

What would the result be if a specific sigma subunit were mutated?
a.Nothing would result: sigma is not essential.
b.RNA polymerase would still bind at specific sites,but elongation would fail.
c.RNA polymerase would fail to initiate transcription at the promoter specific to the sigma subunit.
d. The core enzyme would not be stable.

Accepted Answer

The sigma subunit assists RNA polymerase in binding to a specific promoter sequence. If the sigma subunit were mutated, RNA polymerase would no longer be able to initiate transcription at the promoter specific to the sigma subunit.

Question 8

What is the most likely result from mutating a prokaryotic Shine-Dalgarno sequence?
a.The translated protein would have different amino acids.
b.The mRNA would be less stable.
c.The ribosome would not be able to bind to the mRNA.
d.None of the above: prokaryotes do not have a Shine-Dalgarno sequence.

Accepted Answer

Mutating the Shine-Dalgarno sequence would affect the ability of the ribosome to properly bind to the mRNA, therefore inhibiting translation. It would not affect the amino acid sequence of the protein produced, nor the stability of the mRNA, which is more related to changes in the 5' and 3' untranslated regions. Prokaryotes do have a Shine-Dalgarno sequence, so D is not a valid option.

Question 9

Small interfering RNA siRNAmolecules block gene expression by degrading mRNA or inhibiting transcription.Which genes do they target?
a.genes from which they were transcribed
b.genes that they were not transcribed from
c.random genes
d.none of the above

Accepted Answer

siRNA molecules target genes from which they were transcribed.

Question 10

Which intron component is the first to be cleaved during the splicing process?&#10;a.5' splice site&#10;b.3' splice site&#10;c.branch point&#10;d.depends upon the species

Accepted Answer

The 5' splice site is recognized by the spliceosome as the first component to be cleaved during the splicing process. This initiates the intron removal and exon ligation steps.

Question 11

Which is NOT true of ribosomes?&#10;a.They are composed of proteins and ribosomal RNA molecules.&#10;b.They are made up of only ribosomal RNA molecules.&#10;c.They contain a small subunit and a large subunit.&#10;d.RNAs undergo extensive processing.

Accepted Answer

The answer of Which is NOT true of ribosomes?&#10;a.They are...

Question 12

What kind of RNA functions in splicing and is associated with the spliceosome?&#10;a.transfer RNA tRNA)&#10;b.ribosomal RNA rRNA)&#10;c.small nuclear RNA snRNA)&#10;d.none of the above

Accepted Answer

The answer of What kind of RNA functions in splicing...

Deck 10: From DNA to Proteins: Transcription and Rna Processing