$$5'\text{-}TTGACA\text{-}3' at $$the −35 position

Question 1

Which of the following statements best describes the difference between purine and pyrimidine ribonucleotides in RNA?

Accepted Answer

Purine ribonucleotides contain adenine or guanine bases, while pyrimidine ribonucleotides contain cytosine or uracil bases.

Question 2

During RNA synthesis, which enzyme catalyzes the formation of phosphodiester bonds between adjacent ribonucleotides?

Accepted Answer

RNA polymerase

Question 3

Which of the following is a function of the 5′ cap added to eukaryotic mRNA during posttranscriptional processing?

Accepted Answer

It facilitates the export of mRNA from the nucleus to the cytoplasm.

Question 4

A mutation in the −10 consensus sequence (Pribnow box) of a bacterial promoter would most likely result in:

Accepted Answer

Decreased binding of RNA polymerase and reduced transcription initiation.

Question 5

Which of the following best explains why eukaryotic genes can produce more proteins than the number of genes present in the genome?

Accepted Answer

Alternative splicing of pre-mRNA allows for different combinations of exons in mature mRNA.

Question 6

Which of the following sequences is recognized by the sigma subunit of bacterial RNA polymerase during promoter recognition?

Accepted Answer

$$5'	ext{-}TTGACA	ext{-}3' at $$the −35 position

Question 7

Which of the following is a direct result of intrinsic (rho-independent) termination in bacterial transcription?

Accepted Answer

The formation of a stem-loop (hairpin) structure in the mRNA followed by a string of uracils.

Question 8

Which of the following statements about eukaryotic transcription is correct?

Accepted Answer

Eukaryotic transcription factors are required for RNA polymerase II to recognize and bind to promoter sequences.

Question 9

A researcher mutates the branch point adenine in a pre-mRNA intron. What is the most likely consequence?

Accepted Answer

The intron will not be removed, resulting in abnormal mRNA.

Question 10

Which of the following best describes the function of enhancer sequences in eukaryotic gene regulation?

Accepted Answer

They bind activator proteins and increase the level of transcription by interacting with promoter-bound proteins.

Question 11

Which of the following is a key difference between bacterial and eukaryotic transcription termination?

Accepted Answer

Bacterial termination can involve rho protein, while eukaryotic termination involves the torpedo model with RNase.

Question 12

A mutation in the CAAT box of a eukaryotic promoter would most likely affect:

Accepted Answer

The efficiency of transcription initiation by RNA polymerase II.

Question 13

Which of the following is NOT a function of the 3′ poly-A tail in eukaryotic mRNA?

Accepted Answer

Initiating transcription at the promoter.

Question 14

Which of the following best explains why the genetic code is described as 'degenerate'?

Accepted Answer

Multiple codons can specify the same amino acid.

Question 15

Which of the following is a consequence of a frameshift mutation in a protein-coding gene?

Accepted Answer

All codons downstream of the mutation are altered, potentially changing the entire amino acid sequence.

Question 16

Which of the following is true regarding the role of the sigma subunit in bacterial RNA polymerase?

Accepted Answer

It confers promoter specificity to the RNA polymerase core enzyme.

Question 17

Which of the following is a real-world application of the universality of the genetic code?

Accepted Answer

Bacteria can be engineered to produce human insulin.

Question 18

Which of the following best describes the process of alternative polyadenylation?

Accepted Answer

It produces different mature mRNAs by using more than one polyadenylation signal in a gene.

Question 19

Which of the following is a function of small nuclear RNAs (snRNAs) in eukaryotic cells?

Accepted Answer

They participate in the splicing of pre-mRNA by forming part of the spliceosome.

Transcription and RNA Processing: From DNA to Functional RNA

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