Question 1

Which of the following best describes a plasmid in bacterial cells?

Accepted Answer

A circular auxiliary genetic element that can be transmitted between cells and often encodes useful genes.

Question 2

During Sanger sequencing, what is the role of dideoxynucleotide triphosphates (ddNTPs)?

Accepted Answer

They terminate DNA synthesis at specific nucleotides, allowing the sequence to be determined.

Question 3

Which of the following is a key difference between DNA and RNA molecules?

Accepted Answer

RNA contains ribose and uracil.

Question 4

A bacterial gene is transcribed from the following DNA template strand: $$3' - ATCGGCTAGTG - 5'. $$What is the resulting mRNA sequence?

Accepted Answer

$$5' - UAGCCGAUCAC - 3'$$

Question 5

What is the function of the sigma factor in bacterial transcription?

Accepted Answer

It recognizes promoter sequences and helps RNA polymerase initiate transcription.

Question 6

Which of the following best describes an operon in bacteria?

Accepted Answer

A group of genes transcribed together as a single polycistronic mRNA, usually involved in a shared metabolic pathway.

Question 7

Which process allows ribosomes to begin translating mRNA while it is still being synthesized in bacteria?

Accepted Answer

Transcription-translation coupling

Question 8

Which of the following is true about Rho-dependent transcription termination in bacteria?

Accepted Answer

It involves the Rho protein binding to the rut site on the RNA and using ATP hydrolysis to release RNA polymerase.

Question 9

Which sequence is most commonly recognized by the TATA-binding protein (TBP) in archaeal and eukaryotic promoters?

Accepted Answer

A 6–8 base pair 'TATA' box located 18–27 nucleotides upstream of the transcriptional start site.

Question 10

Which of the following statements about next-generation sequencing (NGS) is correct?

Accepted Answer

NGS allows millions of DNA strands to be sequenced in parallel, using principles similar to Sanger sequencing.

Question 11

Which of the following best explains why bacterial mRNA does not require splicing before translation?

Accepted Answer

Bacterial genes lack introns, so splicing is unnecessary.

Question 12

Which of the following is a unique feature of eukaryotic transcription compared to bacterial transcription?

Accepted Answer

Eukaryotes have three different RNA polymerases, each responsible for transcribing different types of genes.

Question 13

A mutation in the sigma factor gene of a bacterium would most likely result in which of the following?

Accepted Answer

Inability to recognize promoter sequences, leading to reduced or absent transcription initiation.

Question 14

Which of the following best describes the directionality of RNA synthesis by RNA polymerase?

Accepted Answer

Synthesizes RNA in the 5’ → 3’ direction, reading the template 3’ → 5’.

Question 15

Which of the following is a real-world application of understanding bacterial operons?

Accepted Answer

Designing antibiotics that target polycistronic mRNA to disrupt bacterial metabolic pathways.

Question 16

Which of the following is a plausible consequence if the rut site in a bacterial gene is mutated so that Rho protein cannot bind?

Accepted Answer

Transcription termination will fail, resulting in abnormally long mRNA transcripts.

Question 17

Which of the following statements about archaeal transcription is correct?

Accepted Answer

Archaea use a single RNA polymerase that is more similar to eukaryotic RNA polymerases than to bacterial RNA polymerase.

Question 18

Which of the following best describes the process of splicing in eukaryotic cells?

Accepted Answer

Removal of introns and joining of exons in the nucleus by the spliceosome.

Question 19

Which of the following is a critical insight gained from the E. coli genome clock experiment?

Accepted Answer

The physical relationship of genes on the chromosome can be mapped based on the time required for gene transfer during conjugation.

Genomes, Genes, and Transcription in Microbiology

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