Question 1

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

Accepted Answer

DNA leads to mRNA, which leads to protein

Question 2

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

Accepted Answer

Helicase

Question 3

A mutation changes a codon from UAU (tyrosine) to UAA (stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 4

Which of the following statements about bacterial chromosomes is correct?

Accepted Answer

They are circular and found in the cytoplasm

Question 5

What is the role of Okazaki fragments in DNA replication?

Accepted Answer

They are short DNA fragments synthesized on the lagging strand

Question 6

Which process describes the transfer of genetic material from one bacterium to another via a bacteriophage?

Accepted Answer

Transduction

Question 7

Which of the following is true about inducible operons such as the lac operon?

Accepted Answer

They are turned on by the presence of an inducer

Question 8

A chemical mutagen causes adenine to pair with cytosine instead of thymine. Which mutagen is responsible for this?

Accepted Answer

Nitrous acid

Question 9

Which of the following best explains why frameshift mutations are often more severe than point mutations?

Accepted Answer

They shift the reading frame, altering all downstream amino acids

Question 10

In eukaryotic cells, what is the function of small nuclear ribonucleoproteins (snRNPs)?

Accepted Answer

They remove introns and splice exons together in mRNA processing

Question 11

Which of the following statements about plasmids is correct?

Accepted Answer

They are self-replicating circular DNA molecules

Question 12

Which enzyme is responsible for joining Okazaki fragments during DNA replication?

Accepted Answer

DNA ligase

Question 13

Which of the following is an example of horizontal gene transfer?

Accepted Answer

A bacterium acquiring DNA from another bacterium in the same generation

Question 14

Which of the following best describes the function of microRNAs (miRNAs) in gene regulation?

Accepted Answer

They base pair with mRNA, making it double-stranded and targeting it for destruction

Question 15

Which of the following is a direct result of UV radiation on DNA?

Accepted Answer

Formation of thymine dimers

Question 16

A bacterium is exposed to a mutagen that causes the insertion of a single nucleotide into a gene. What is the most likely outcome?

Accepted Answer

A frameshift mutation

Question 17

Which of the following best describes the role of the operator in an operon?

Accepted Answer

It is the segment of DNA that controls transcription of structural genes

Question 18

Which of the following is NOT a characteristic of transposons?

Accepted Answer

They are always beneficial to the host cell

Question 19

Which of the following equations correctly represents the hydrolysis of ATP to provide energy for DNA replication?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy}$$

Question 20

A patient is infected with a bacterial strain that has acquired antibiotic resistance through a plasmid. Which genetic process most likely contributed to this resistance?

Accepted Answer

Horizontal gene transfer via conjugation

Microbial Genetics: Structure, Function, and Regulation

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