Question 1

Which of the following best describes the flow of genetic information in a cell according to the central dogma of molecular biology?

Accepted Answer

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

Question 2

During DNA replication in E. coli, which enzyme is primarily responsible for synthesizing the new DNA strand, and in which direction does this synthesis occur?

Accepted Answer

DNA polymerase III; 5' to 3' direction

Question 3

Which of the following statements about plasmids is TRUE?

Accepted Answer

Plasmids are generally beneficial for the cell, often carrying genes such as those for antibiotic resistance.

Question 4

A segment of DNA that can move from one site to another within the genome, sometimes inserting itself into other DNA molecules, is known as:

Accepted Answer

A transposable element

Question 5

Which of the following best explains why the lagging strand is synthesized in fragments during DNA replication?

Accepted Answer

DNA polymerase can only synthesize DNA in the 5' to 3' direction, so the lagging strand is made discontinuously as Okazaki fragments.

Question 6

Which of the following is NOT a function of RNA polymerase during transcription?

Accepted Answer

Proofreading the newly synthesized RNA for errors

Question 7

In bacteria, what is the role of the sigma factor during transcription initiation?

Accepted Answer

It helps RNA polymerase recognize and bind to the promoter region.

Question 8

Which of the following best describes a polycistronic mRNA?

Accepted Answer

An mRNA that encodes multiple proteins, typically found in prokaryotes.

Question 9

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

Accepted Answer

Eukaryotic mRNA often undergoes capping, polyadenylation, and splicing, while prokaryotic mRNA does not.

Question 10

Which of the following codons is a start codon in the genetic code?

Accepted Answer

AUG

Question 11

A mutation causes a shift in the reading frame of an mRNA by one nucleotide. What is the likely consequence of this frameshift mutation?

Accepted Answer

The amino acid sequence downstream of the mutation will be altered, potentially resulting in a nonfunctional protein.

Question 12

Which of the following best describes the 'wobble' hypothesis in tRNA-codon pairing?

Accepted Answer

The third base of the codon can form non-standard base pairs with the tRNA anticodon, allowing one tRNA to recognize multiple codons.

Question 13

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

Accepted Answer

A site

Question 14

Which of the following is the correct sequence of events during protein synthesis?

Accepted Answer

Initiation, elongation, termination

Question 15

Which of the following statements about stop codons is TRUE?

Accepted Answer

Stop codons do not code for any amino acid and signal the termination of translation.

Question 16

A researcher isolates a bacterial mRNA that encodes three proteins from a single transcript. What is this genetic organization called, and what is its advantage?

Accepted Answer

An operon; it allows coordinated expression of functionally related genes.

Question 17

Which of the following best explains the function of the Shine-Dalgarno sequence in prokaryotic mRNA?

Accepted Answer

It helps the ribosome recognize the correct start site for translation.

Question 18

Which of the following processes requires a primer to begin synthesis?

Accepted Answer

DNA replication

Question 19

In eukaryotic cells, which of the following modifications occurs to pre-mRNA before it becomes mature mRNA?

Accepted Answer

Addition of a 5' cap and a 3' poly(A) tail, and removal of introns

Question 20

A patient is infected with a bacterium that is resistant to multiple antibiotics. Which genetic element is most likely responsible for this resistance?

Accepted Answer

A plasmid carrying antibiotic resistance genes

Ch. 6. Molecular Information Flow and Protein Processing in Microbiology

Study Guide - Practice Questions

Study Guide - Flashcards