Q: Which of the following equations correctly represents the calculation of the melting temperature ($$T_m) of a $$DNA duplex with the formula for short oligonucleotides?

$$T_m = 2 \times (A+T) + 4 \times (G+C)$$

Question 1

Which of the following best describes the role of the TATA box in eukaryotic transcription initiation?

Accepted Answer

It serves as a promoter element recognized by transcription factors to help position RNA polymerase II at the correct start site.

Question 2

During mRNA processing in eukaryotes, which modification is essential for mRNA stability and export from the nucleus?

Accepted Answer

Addition of a poly-A tail at the 3' end

Question 3

A mutation in the spliceosome machinery would most likely affect which process?

Accepted Answer

Removal of introns from pre-mRNA

Question 4

Which of the following equations correctly represents the calculation of the melting temperature ($$T_m) of a $$DNA duplex with the formula for short oligonucleotides?

Accepted Answer

$$T_m = 2 	imes (A+T) + 4 	imes (G+C)$$

Question 5

In prokaryotic transcription, what is the function of the sigma ($$\sigma) $$factor?

Accepted Answer

It recognizes promoter sequences and helps RNA polymerase bind to DNA.

Question 6

Which of the following is a consequence of alternative splicing in eukaryotes?

Accepted Answer

It allows a single gene to produce multiple protein isoforms.

Question 7

A patient is found to have a mutation in the polyadenylation signal sequence of a gene. Which of the following is the most likely effect?

Accepted Answer

Impaired addition of the poly-A tail, leading to unstable mRNA

Question 8

Which of the following best explains why prokaryotic mRNA can be translated while it is still being transcribed?

Accepted Answer

Transcription and translation are coupled because there is no nuclear membrane.

Question 9

Which of the following is NOT a function of the 5' cap added to eukaryotic mRNA?

Accepted Answer

Initiation of polyadenylation at the 3' end

Question 10

During translation, which site on the ribosome does the incoming aminoacyl-tRNA bind to?

Accepted Answer

A site

Question 11

A researcher is studying a gene with the following coding sequence: 5'-ATG GAA TGC TAA-3'. What is the sequence of the mRNA transcribed from this gene?

Accepted Answer

5'-AUG GAA UGC UAA-3'

Question 12

Which of the following statements about the genetic code is correct?

Accepted Answer

It is universal, with few exceptions among organisms.

Question 13

Which enzyme is responsible for charging tRNA molecules with their corresponding amino acids?

Accepted Answer

Aminoacyl-tRNA synthetase

Question 14

A mutation changes a codon from UAU (tyrosine) to UAA (stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 15

Which of the following best describes the process of RNA editing?

Accepted Answer

Addition or deletion of nucleotides in the RNA sequence after transcription

Question 16

In eukaryotic translation initiation, which of the following is required for the small ribosomal subunit to recognize the start codon?

Accepted Answer

5' cap structure

Question 17

Which of the following is a direct result of the wobble hypothesis in tRNA-codon pairing?

Accepted Answer

Some tRNAs can recognize multiple codons for the same amino acid.

Question 18

A scientist observes that a certain mRNA is rapidly degraded in the cytoplasm. Which of the following is most likely missing from this mRNA?

Accepted Answer

Poly-A tail

Question 19

Which of the following best explains the function of snRNPs (small nuclear ribonucleoproteins) in eukaryotic cells?

Accepted Answer

They catalyze the splicing of pre-mRNA by recognizing splice sites.

Question 20

A geneticist is analyzing a gene that undergoes alternative splicing, producing two different mRNAs. If the gene contains 5 exons, what is the minimum number of exons that must be present in both mRNAs for them to encode functional proteins?

Accepted Answer

At least the exons encoding the start and stop codons must be present.

Transcription and Translation in Genetics: Mechanisms and Regulation

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