Question 1

In eukaryotes, RNA polymerase II
A) is the most alpha-amanitin resistant polymerase.
B) is responsible for formation of tRNAs and other small RNAs.
C) often initiates transcription at complex promoters containing enhancers, silencers and TATA sequences.
D) terminates RNA synthesis and releases the RNA chain at AATAA sequences specifying end formation and polyadenylation.
E) normally utilizes bidirectional promoters.

Accepted Answer

RNA polymerase II typically initiates transcription at complex promoters that contain enhancers, silencers, and a TATA box sequence. These sequences help to regulate the transcriptional activity of the gene.

Answer: A 
 RNA polymerase II is the least sensitive to alpha-amanitin, a toxin that specifically inhibits RNA polymerase II activity.

Answers B, D, and E are incorrect. RNA polymerase III is responsible for small RNA synthesis (like tRNAs), RNA polymerase II does not terminate RNA synthesis at specific end sequences (AATAA), and bidirectional promoters are typically utilized by RNA polymerase II and III.

Question 2

During nuclear processing of an pre-mRNA in a eukaryote, the portions discarded are
A) exons.
B) introns.
C) duplicate genes.
D) methylated regions.
E) poly A chains.

Accepted Answer

During nuclear processing of pre-mRNA in eukaryotes, the introns (non-coding sequences) are spliced out and discarded, while the exons (coding sequences) are put together to form the mature mRNA transcript. Duplicate genes, methylated regions, and poly A chains are not specifically involved in this process.

Question 3

Mammalian RNA polymerase II
A) synthesizes rRNA.
B) synthesizes mRNA.
C) synthesizes tRNA.
D) is least sensitive to alpha-amanitin.
E) None of the other answers is correct.

Accepted Answer

Mammalian RNA polymerase II synthesizes mRNA, which is responsible for carrying genetic information from DNA to the ribosome for protein synthesis.

Question 4

Splicing occurs
A) in the nucleus, by removing introns from DNA.
B) in the nucleus, prior to transcription.
C) in the nucleus, either during or subsequent to transcription.
D) in the cytoplasm, prior to translation.
E) in the cytoplasm, subsequent to translation.

Accepted Answer

Splicing occurs in the nucleus, either during or subsequent to transcription, where introns are removed from pre-mRNA to produce mature mRNA that can be exported to the cytoplasm for translation.

Question 5

If the DNA strand which is complementary to the strand of DNA which is transcribed into RNA has the following base sequence A G C T C A C T G The RNA transcribed would have which of the following sequences?
A) C A G U G A G C U
B) A G C U C A C U G
C) A G C T C A C T G
D) C A G T G A G C U
E) None of the other answers is correct.

Accepted Answer

RNA uses uracil (U) instead of thymine (T), so the complementary RNA strand would have the base sequence UCGAGUGA. The only answer option with that base sequence is B.

Question 6

Which one of the following statements is true about eukaryotic RNA polymerases?
A) polymerase I is responsible for transcription of ribosomal RNA.
B) polymerase I is located in the nucleolus.
C) polymerase III is insensitive to alpha_amanitin.
D) polymerase II requires sigma factor to initiate RNA synthesis.
E) polymerase III carries out the splicing of tRNA precursors.

Accepted Answer

The answer of Which one of the following statements is...

Question 7

Which of the following is a characteristic of transcription?
A) the reaction is driven toward product formation by hydrolysis of pyrophosphate.
B) a short primer, complementary to the DNA template, is required to initiate transcription.
C) ATP serves as the energy requirement for each new phosphodiester bond.
D) GTP serves as the energy requirement for each new phosphodiester bond.
E) the reaction is "semi_Conservative" with respect to the DNA template.

Accepted Answer

Transcription involves the synthesis of RNA from a DNA template. The energy for the formation of the phosphodiester bonds between nucleotides in the RNA molecule comes from the nucleotide triphosphates themselves (ATP, GTP, CTP, UTP). When these nucleotides are incorporated into the growing RNA chain, pyrophosphate (PPi) is released and subsequently hydrolyzed to two molecules of inorganic phosphate (Pi). This hydrolysis of pyrophosphate drives the reaction forward, making it energetically favorable.

Question 8

Which one of the following is wrong? RNA splicing.
A) is responsible for the joining of V, D, and J segments in formation of a heavy chain immunoglobulin protein.
B) is sometimes an autocatalytic reaction which can occur without added proteins.
C) is often mediated by particles called spliceosomes containing both RNAs and proteins.
D) occurs in the nucleus to form a complete, translatable mRNA with a single open reading frame.
E) often results in the excision of the intron as a structure known as a lariat.

Accepted Answer

RNA splicing is a process primarily involved in the removal of introns and joining of exons in pre-mRNA to form mature mRNA. The joining of V, D, and J segments in the formation of a heavy chain immunoglobulin protein is a process known as V(D)J recombination, which is distinct from RNA splicing and involves the rearrangement of genetic material at the DNA level, not RNA.

Question 9

The first step in eukaryotic pre-mRNA splicing is
A) ligation of the two exon sequences.
B) cleavage of the intron sequence at the branch site.
C) ligation of the branch site adenosine to the 5' end of the intron.
D) cleavage of the intron sequence at the 3' end.
E) ligation of U1 snRNA to the branch site.

Accepted Answer

The first step in eukaryotic pre-mRNA splicing involves the formation of a lariat structure, where the branch site adenosine attacks the 5' splice site, creating a loop.

Question 10

Capping of prokaryotic monocistronic mRNA's allows correct translation in a eukaryotic translation system. This result is evidence for
A) a role for 7-methyl-GpppNp in the recognition of mRNA by eukaryotic initiation factors and/or ribosomes.
B) a role for poly A in mRNA selection.
C) a role for F-met-tRNA in protein recognition.
D) a malfunctioning prokaryotic RNA-polymerase.
E) the production of monocistronic mRNA's in eukaryotes.

Accepted Answer

The capping of prokaryotic monocistronic mRNA's allows recognition by eukaryotic initiation factors and/or ribosomes through the 7-methyl-GpppNp cap. This indicates that there is a role for the cap in the translation of eukaryotic mRNA's, supporting choice A as the correct answer. Choice B (poly A) and choice C (F-met-tRNA) are not relevant to capping of mRNA, and choices D and E are not supported by the information given in the question.

Question 11

With regard to RNA polymerases of eukaryotic cells
A) polymerase I activity is highly sensitive to inhibition by alpha-amanitin.
B) polymerase II is localized primarily in the nucleolus.
C) polymerase III is responsible for tRNA and 5S ribosomal RNA synthesis.
D) polymerase I is localized primarily in the nucleoplasm.
E) polymerase II is responsible for 18S and 28S ribosomal RNA synthesis.

Accepted Answer

Polymerase III is responsible for the synthesis of tRNA and 5S ribosomal RNA in eukaryotic cells.

Question 12

Which of the following describes the function of factor rho?
A) Rho binds RNA polymerase to the promoter region.
B) Rho brings about proper initiation of transcription.
C) Rho brings about correct termination of transcription.
D) Rho binds catabolite repressor protein to the promoter region.
E) Rho increases the rate of elongation of the growing RNA chain.

Accepted Answer

Factor Rho is responsible for the termination of transcription. It binds to the nascent RNA chain and causes it to dissociate from the RNA polymerase, releasing the completed RNA molecule.

Question 13

A one nucleotide slip in the splice point on the side of the splice junction in the first intron of the beta-globin gene would result in
A) changing the reading frame of the mRNA from this point onward.
B) deletion of the rest of the beta-globin gene.
C) no change in the protein as all coding information is 5' to this junction.
D) a transition mutation.
E) a transversion mutation.

Accepted Answer

A one nucleotide slip in the splice point on the side of the splice junction in the first intron of the beta-globin gene would shift the reading frame of the mRNA, resulting in a different sequence of amino acids in the encoded protein. This is known as a frameshift mutation. This change can have significant consequences for the structure and function of the protein.

Question 14

The two largest rRNA molecules are formed
A) by partial degradation of a single, large RNA molecule.
B) on two separate genomes.
C) by condensation of two or more mRNA species.
D) by translation of mRNA.

Accepted Answer

The two largest rRNA molecules (28S and 18S) are formed by partial degradation of a single, large RNA molecule called pre-rRNA. This pre-rRNA is processed to remove non-coding sequences and fold into functional rRNA molecules.

Question 15

RNA splicing involves
A) the removal of exons.
B) the assembly of ribosomes.
C) transcription initiation factors.
D) the removal of introns.
E) DNA rearrangements.

Accepted Answer

RNA splicing involves the removal of introns from pre-mRNA. Exons are the coding regions and are retained in the mature mRNA. Assembly of ribosomes is not directly involved in RNA splicing. Transcription initiation factors are involved in initiating transcription but not splicing. DNA rearrangements are not involved in RNA splicing.

Question 16

RNA polymerases and DNA polymerases have in common the property that they both
A) require a primer for their activity.
B) have proofreading activity.
C) synthesize polynucleotides in a 5' to 3' direction.
D) have exonuclease activity.

Accepted Answer

Both RNA polymerases and DNA polymerases synthesize polynucleotides in a 5' to 3' direction. However, RNA polymerases do not require a primer for their activity, and they do not have proofreading or exonuclease activity, whereas DNA polymerases have both of these properties. Therefore, options A and D are incorrect, and option B is only true for DNA polymerases.

Question 17

Intervening sequences (introns) are
A) found in cDNA clones.
B) only found in eukaryotic DNA.
C) removed during DNA replication.
D) found in genomic DNA and hnRNA.
E) added to mRNA by the spliceosome.

Accepted Answer

Intervening sequences, also known as introns, are only found in eukaryotic genomic DNA and hnRNA (heterogeneous nuclear RNA). They are removed through the process of RNA splicing, which occurs during transcription to form mature mRNA molecules without introns. In contrast, cDNA clones are produced from mature mRNA molecules and do not contain introns. Therefore, choice D is the best answer.

Question 18

Which of the following is a correct statement about the process of transcription?
A) The process of transcription involves the formation of tRNA, rRNA, as well as mRNA.
B) transcription starts at a random DNA sequence.
C) Initiation of transcription is inhibited by actinomycinD.
D) RNA synthesized is complementary to one of the DNA strands and has the same polarity as the template strand.

Accepted Answer

Transcription involves the synthesis of mRNA, tRNA, and rRNA from a DNA template.

Question 19

All of the following are true EXCEPT which one?
A) Most eukaryotic RNA never leaves the nucleus.
B) Essentially all types of eukaryotic RNA undergo post-transcriptional modification.
C) All forms of RNA are synthesized by some RNA polymerase.
D) The preferred template of eukaryotic RNA polymerases is double-stranded DNA.
E) The direction of RNA synthesis is to 5'.

Accepted Answer

The direction of RNA synthesis is actually 5' to 3', not 5' as stated in option E. The other options are true - most eukaryotic RNA stays in the nucleus, all types of eukaryotic RNA are modified after transcription, all forms of RNA are made by RNA polymerase, and the preferred template for eukaryotic RNA polymerases is double-stranded DNA.

Question 20

Which of the following is a characteristic of transcription?
A) A short primer, complementary to the DNA template, is required to initiate transcription.
B) ATP serves as the energy requirement for each new phosphodiester bond.
C) The reaction is driven toward product formation by hydrolysis of pyrophosphate.
D) The coding information is contained within the RNA polymerase.
E) The reaction is semi-conservative with respect to the DNA template.

Accepted Answer

The transcription process is driven forward by the hydrolysis of pyrophosphate, which is released when nucleotides are added to the growing RNA chain.

Quiz 5: RNA: Transcription and Rna Processing

In eukaryotes, RNA polymerase II

During nuclear processing of an pre-mRNA in a eukaryote, the portions discarded are

Mammalian RNA polymerase II

Splicing occurs

If the DNA strand which is complementary to the strand of DNA which is transcribed into RNA has the following base sequence A G C T C A C T G The RNA transcribed would have which of the following sequences?

Which one of the following statements is true about eukaryotic RNA polymerases?

Which of the following is a characteristic of transcription?

Which one of the following is wrong? RNA splicing.

The first step in eukaryotic pre-mRNA splicing is

Capping of prokaryotic monocistronic mRNA's allows correct translation in a eukaryotic translation system. This result is evidence for

With regard to RNA polymerases of eukaryotic cells

Which of the following describes the function of factor rho?

A one nucleotide slip in the splice point on the side of the splice junction in the first intron of the beta-globin gene would result in

The two largest rRNA molecules are formed

RNA splicing involves

RNA polymerases and DNA polymerases have in common the property that they both

Intervening sequences (introns) are

Which of the following is a correct statement about the process of transcription?

All of the following are true EXCEPT which one?

Which of the following is a characteristic of transcription?