Question 1

Which of the following best describes the Central Dogma of Molecular Biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

Which subunit of the E. coli RNA polymerase holoenzyme is primarily responsible for recognizing the promoter sequence?

Accepted Answer

The $$ \sigma $$ subunit

Question 3

A mutation in the Pribnow box of a bacterial promoter is most likely to result in which of the following?

Accepted Answer

A significant decrease in transcription initiation

Question 4

Which of the following statements about RNA polymerase in prokaryotes is FALSE?

Accepted Answer

It requires a primer to initiate RNA synthesis.

Question 5

Which of the following modifications is NOT found in prokaryotic mRNA but is essential for eukaryotic mRNA maturation?

Accepted Answer

Addition of a 5' cap and a 3' poly-A tail

Question 6

Which of the following best explains why eukaryotic mRNA is typically much smaller than the gene from which it is transcribed?

Accepted Answer

Introns are removed from the pre-mRNA during processing.

Question 7

Which of the following is a function of the 5' cap added to eukaryotic mRNA?

Accepted Answer

Protection from nuclease attack

Question 8

A researcher isolates a eukaryotic cell and finds a mutation that prevents the formation of snRNPs. Which process will be most directly affected?

Accepted Answer

Splicing of pre-mRNA

Question 9

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

Accepted Answer

It is a core promoter element that determines where RNA polymerase II binds and initiates transcription.

Question 10

Which of the following is TRUE regarding the products of the three eukaryotic RNA polymerases?

Accepted Answer

RNA polymerase I synthesizes rRNA, RNA polymerase II synthesizes mRNA and snRNA, and RNA polymerase III synthesizes 5S rRNA and tRNA.

Question 11

A bacterial gene is mutated so that its -10 region (Pribnow box) is changed from TATAAT to TATGGT. What is the most likely outcome?

Accepted Answer

Transcription initiation will be significantly reduced.

Question 12

Which of the following statements about polycistronic mRNA is correct?

Accepted Answer

It is found in prokaryotes and encodes more than one protein.

Question 13

Which of the following best describes a ribozyme?

Accepted Answer

An RNA molecule capable of catalyzing its own splicing

Question 14

During the elongation phase of transcription in E. coli, which event occurs after the synthesis of the first 8–9 nucleotides?

Accepted Answer

The $$ \sigma $$ subunit dissociates from the RNA polymerase.

Question 15

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

Accepted Answer

Eukaryotic transcription requires chromatin remodeling and multiple RNA polymerases.

Question 16

A patient is found to have a genetic disorder caused by improper removal of introns from pre-mRNA. Which cellular structure is most likely defective?

Accepted Answer

The spliceosome

Question 17

Which of the following best describes the chemical difference between ribose and deoxyribose?

Accepted Answer

Ribose has a hydroxyl group (OH) at the 2' carbon, while deoxyribose has a hydrogen (H) at the same position.

Question 18

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

Accepted Answer

Initiation of transcription

Question 19

Which of the following best explains why prokaryotic mRNA can be translated immediately after transcription?

Accepted Answer

Transcription and translation both occur in the cytoplasm without a nuclear envelope.

Question 20

A scientist discovers a new eukaryotic gene with 10 exons and 9 introns. After transcription and processing, which of the following is true about the mature mRNA?

Accepted Answer

It will contain only the 10 exons joined together.

Genetic Code and Transcription: Structure, Mechanisms, and Regulation

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