Question 1

Which of the following statements best describes the difference between a gene, a chromosome, and a genome?

Accepted Answer

A gene is a specific sequence of DNA that codes for a protein or RNA; a chromosome is a DNA molecule with associated proteins; a genome is the entire genetic material of an organism.

Question 2

During DNA replication, which enzyme is responsible for joining Okazaki fragments on the lagging strand?

Accepted Answer

DNA ligase

Question 3

Which of the following best explains why DNA replication is described as 'semiconservative'?

Accepted Answer

Each new DNA molecule consists of one original strand and one newly synthesized strand.

Question 4

A mutation that results in a premature stop codon is called:

Accepted Answer

A nonsense mutation

Question 5

Which of the following is a key difference between prokaryotic and eukaryotic chromosomes?

Accepted Answer

Prokaryotic chromosomes are usually circular and found in the nucleoid, while eukaryotic chromosomes are linear and found in the nucleus.

Question 6

If a gene codes for a protein that is 5 amino acids long, how many nucleotides are required to code for this protein (excluding the stop codon)?

Accepted Answer

$$5 	imes 3 = 15$$

Question 7

Which of the following best describes the function of a plasmid in bacteria?

Accepted Answer

A plasmid is a small, circular DNA molecule that replicates independently and can carry genes for antibiotic resistance or virulence.

Question 8

Which of the following is NOT a difference between DNA and RNA?

Accepted Answer

DNA is found only in the cytoplasm, while RNA is found only in the nucleus.

Question 9

Which of the following is a correct sequence of events in the central dogma of molecular biology?

Accepted Answer

DNA $$\rightarrow$$ RNA $$\rightarrow$$ Protein

Question 10

A bacterium is exposed to UV light, which causes adjacent thymines to bond together. What type of mutation is this, and what is the result?

Accepted Answer

Nonionizing radiation causes thymine dimers, which distort the DNA and block replication and transcription.

Question 11

Which of the following best describes the process of transformation in bacteria?

Accepted Answer

Uptake of naked DNA from the environment by a competent cell.

Question 12

Which of the following is true about Okazaki fragments?

Accepted Answer

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

Question 13

Which of the following is a function of DNA methylation in bacteria?

Accepted Answer

Control of genetic expression, initiation of DNA replication, protection against viral infection, and DNA repair.

Question 14

Which of the following is a correct match between a type of mutation and its effect?

Accepted Answer

Frameshift mutation: alters the reading frame, changing all downstream amino acids.

Question 15

Which of the following is a key feature of eukaryotic DNA replication that distinguishes it from prokaryotic DNA replication?

Accepted Answer

Eukaryotic chromosomes have thousands of origins of replication, while prokaryotic chromosomes have only one.

Question 16

Which of the following best describes the role of tRNA during translation?

Accepted Answer

tRNA delivers the correct amino acid to the ribosome by matching its anticodon to the mRNA codon.

Question 17

Which of the following is a real-world example of horizontal gene transfer in bacteria?

Accepted Answer

A bacterium acquires antibiotic resistance by receiving a plasmid from another bacterium via conjugation.

Question 18

Which of the following is a correct description of a transposon?

Accepted Answer

A segment of DNA that can move from one location to another within a genome, potentially disrupting genes.

Question 19

Which of the following best explains why gene expression is regulated in bacteria?

Accepted Answer

To conserve energy by only producing proteins when needed.

Question 20

Which of the following is a difference between generalized and specialized transduction?

Accepted Answer

Generalized transduction transfers random DNA segments; specialized transduction transfers only specific genes near the prophage insertion site.

Microbial Genetics: Structure, Replication, Transcription, and Translation

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