Question 1

Which of the following best describes the role of transcription in the central dogma of molecular biology?

Accepted Answer

Transcription copies DNA into an RNA molecule, which can then be translated into protein.

Question 2

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

Accepted Answer

It recognizes and binds to the promoter region, guiding RNA polymerase to the correct initiation site.

Question 3

Which of the following statements correctly compares prokaryotic and eukaryotic promoters?

Accepted Answer

Prokaryotic promoters typically have -10 and -35 consensus sequences, while eukaryotic promoters often contain a TATA box around -25.

Question 4

A mutation in a gene's enhancer region affects the binding of a transcription factor. This transcription factor is best described as:

Accepted Answer

A trans-acting factor

Question 5

Which of the following is a key difference between transcription initiation in prokaryotes and eukaryotes?

Accepted Answer

Eukaryotes require assembly of a pre-initiation complex with multiple general transcription factors, while prokaryotes rely mainly on the sigma factor.

Question 6

Given the following DNA template strand: 3'-TACGGTACG-5', what is the corresponding mRNA sequence?

Accepted Answer

5'-AUGCCAUGC-3'

Question 7

Which of the following best describes polycistronic mRNA?

Accepted Answer

An mRNA that contains multiple coding regions, each translated into a different protein.

Question 8

Which of the following is NOT a post-transcriptional modification of eukaryotic pre-mRNA?

Accepted Answer

Attachment of the Shine-Dalgarno sequence

Question 9

A patient has a mutation that prevents the addition of a 5' cap to mRNA. Which of the following is a likely consequence?

Accepted Answer

The mRNA will be rapidly degraded and inefficiently translated.

Question 10

Which of the following statements about the spliceosome is correct?

Accepted Answer

The spliceosome is a complex of snRNAs and proteins that removes introns from pre-mRNA.

Question 11

Alternative splicing allows for which of the following?

Accepted Answer

The production of multiple protein isoforms from a single gene.

Question 12

Which of the following best describes the function of the rho ($$\rho) $$factor in prokaryotic transcription?

Accepted Answer

It terminates transcription by binding to the rut site and causing dissociation of the RNA transcript.

Question 13

If the coding (non-template) DNA strand of a gene is 5'-ATGCGTACC-3', what is the sequence of the mRNA transcribed from this gene?

Accepted Answer

5'-AUGCGUACC-3'

Question 14

Which of the following is a requirement for RNA polymerase activity during transcription?

Accepted Answer

A DNA template and ribonucleotide triphosphates (NTPs)

Question 15

A eukaryotic gene contains four exons (E1, E2, E3, E4) and three introns. Which of the following mRNA isoforms could result from alternative splicing?

Accepted Answer

E1-E3-E4

Question 16

Which of the following is true regarding cis-acting elements?

Accepted Answer

They are DNA sequences that regulate the expression of genes located on the same DNA molecule.

Question 17

A researcher mutates the -10 region of a prokaryotic promoter. What is the most likely effect on transcription?

Accepted Answer

Transcription initiation will be reduced or abolished due to poor sigma factor binding.

Question 18

Which of the following equations correctly represents the direction of RNA synthesis during transcription?

Accepted Answer

$$5' \rightarrow 3'$$

Question 19

A prokaryotic operon produces a single mRNA that encodes three enzymes involved in lactose metabolism. This mRNA is best described as:

Accepted Answer

Polycistronic

Question 20

Which of the following is a direct consequence of improper splicing of pre-mRNA in eukaryotes?

Accepted Answer

The mature mRNA may contain introns, potentially resulting in a nonfunctional protein.

Transcription and RNA Processing Study Guide – Step-by-Step Genetics Guidance

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