$$ \text{dNTP} \rightarrow \text{dNMP} + 2 \text{PP}_i $$

Question 1

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is replicated, transcribed into RNA, and then translated into protein.

Question 2

During DNA replication in bacteria, which enzyme is responsible for unwinding the DNA helix?

Accepted Answer

DnaB helicase

Question 3

Which of the following statements about Okazaki fragments is correct?

Accepted Answer

They are short DNA fragments synthesized on the lagging strand during DNA replication.

Question 4

A mutation changes a single base in a gene, resulting in a normal protein. What type of mutation is this?

Accepted Answer

Silent mutation

Question 5

Which of the following best explains why most bacterial cells are haploid?

Accepted Answer

They possess a single circular genome, so only one copy of each gene is present.

Question 6

Which protein is responsible for proofreading during bacterial DNA replication?

Accepted Answer

DnaQ subunit of DNA Polymerase III

Question 7

In the lac operon, which condition leads to maximal expression of the operon?

Accepted Answer

Low glucose, high lactose

Question 8

Which of the following is a function of the sliding clamp (DnaN) during DNA replication?

Accepted Answer

Increases the processivity of DNA polymerase by preventing its dislocation from DNA

Question 9

Which of the following best describes the role of sigma factor in bacterial transcription?

Accepted Answer

It recognizes and binds the promoter, enabling RNA polymerase to initiate transcription.

Question 10

A bacterial cell is exposed to rifamycin. What is the most likely effect?

Accepted Answer

Inhibition of transcription initiation by binding to RNA polymerase.

Question 11

Which of the following equations correctly represents the energy released during nucleotide incorporation in DNA replication?

Accepted Answer

$$ 	ext{dNTP} ightarrow 	ext{dNMP} + 2 	ext{PP}_i $$

Question 12

Which of the following statements about genotype and phenotype is correct?

Accepted Answer

Phenotypic changes can occur without genotypic changes, often due to environmental factors.

Question 13

Which of the following is true regarding the regulation of the arginine operon?

Accepted Answer

It is regulated by a repressor protein and a corepressor.

Question 14

Which of the following best describes the function of methyl-accepting chemotaxis proteins (MCPs) in bacteria?

Accepted Answer

They sense environmental attractants or repellents and trigger interactions with CheA and CheW.

Question 15

Which of the following is a correct description of endospore formation in bacteria?

Accepted Answer

It is a process regulated by sigma factors and results in a differentiated cell resistant to extreme conditions.

Question 16

Which of the following best explains why the lac operon is not expressed when both glucose and lactose are present?

Accepted Answer

Glucose inhibits the binding of CRP to the promoter, preventing transcription of the lac operon.

Question 17

Which of the following is a real-world example of two-component regulation in bacteria?

Accepted Answer

Sensor kinase detects environmental signal and autophosphorylates, then transfers phosphate to response regulator, which regulates transcription.

Question 18

Which of the following is a plausible consequence of a frameshift mutation in a bacterial gene?

Accepted Answer

Production of a truncated or nonfunctional protein due to altered reading frame.

Question 19

Which of the following molecules acts as an autoinducer in bacterial quorum sensing?

Accepted Answer

Acyl homoserine lactone (AHL)

Question 20

Which of the following best describes the relationship between nucleotides and nucleosides?

Accepted Answer

Nucleotides consist of a nucleoside plus one or more phosphate groups.

Central Dogma, DNA Replication, and Gene Regulation in Bacteria

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