Question 1

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

Accepted Answer

Information flows from DNA to RNA to protein.

Question 2

During DNA replication, which enzyme is primarily responsible for synthesizing the new DNA strand in E. coli?

Accepted Answer

DNA polymerase III

Question 3

Which of the following statements about DNA structure is correct?

Accepted Answer

Adenine pairs with thymine via two hydrogen bonds.

Question 4

What is the role of tRNA during translation?

Accepted Answer

It brings amino acids to the ribosome according to the mRNA codon.

Question 5

Which of the following best explains why negative supercoiling is predominantly found in nature?

Accepted Answer

It underwinds the DNA, facilitating strand separation for replication and transcription.

Question 6

A plasmid is best described as:

Accepted Answer

A genetic element that replicates independently of the host chromosome and is usually circular.

Question 7

Which of the following is NOT a function of the sigma factor in bacterial transcription?

Accepted Answer

Binding to the ribosome to start translation.

Question 8

Which process is described by the equation $DNA \rightarrow RNA$?

Accepted Answer

Transcription

Question 9

In the context of the genetic code, what is meant by 'wobble'?

Accepted Answer

Irregular base pairing allowed at the third position of the codon, enabling one tRNA to recognize multiple codons.

Question 10

Which of the following is a consequence of codon bias?

Accepted Answer

Genes from one organism may not be efficiently translated in another due to differences in tRNA availability.

Question 11

Which enzyme is responsible for removing RNA primers and replacing them with DNA during replication?

Accepted Answer

DNA polymerase I

Question 12

What is the function of the Rho protein in transcription termination?

Accepted Answer

It recognizes specific DNA sequences and causes RNA polymerase to pause, leading to termination.

Question 13

Which of the following best describes the role of the Shine-Dalgarno sequence?

Accepted Answer

It ensures proper reading frame by aligning the ribosome with the start codon on mRNA.

Question 14

Which of the following statements about protein secretion systems is correct?

Accepted Answer

Types I, III, IV, and VI do not require Sec or Tat pathways for protein export.

Question 15

Which of the following is true regarding Okazaki fragments?

Accepted Answer

They are short DNA fragments synthesized discontinuously on the lagging strand.

Question 16

Which of the following is a function of chaperone proteins?

Accepted Answer

They assist in the proper folding of newly synthesized polypeptides.

Question 17

Which of the following is a correct description of an operon?

Accepted Answer

A group of related genes co-transcribed to a polycistronic mRNA, allowing coordinated expression.

Question 18

Which of the following is a direct result of the proofreading activity of DNA polymerase?

Accepted Answer

High fidelity and low error rates in DNA replication.

Question 19

Which of the following is true about the directionality of nucleic acid synthesis?

Accepted Answer

Both DNA and RNA synthesis proceed in the 5' to 3' direction.

Question 20

Which of the following best explains the function of aminoacyl-tRNA synthetase?

Accepted Answer

It attaches the correct amino acid to its corresponding tRNA using ATP.

Molecular Microbiology: Genetic Elements, Central Dogma, and DNA Structure

Study Guide - Practice Questions