Question 1

Which of the following best explains how rRNA is used to classify organisms?

Accepted Answer

rRNA gene sequences are highly conserved, allowing scientists to compare evolutionary relationships among all domains of life.

Question 2

A patient is diagnosed with tuberculosis. Which bacterium is responsible for this disease?

Accepted Answer

Mycobacterium tuberculosis

Question 3

Which of the following statements about viruses is correct?

Accepted Answer

Viruses are not composed of cells and are considered infectious particles.

Question 4

Which of the following best describes a prion?

Accepted Answer

A proteinaceous infectious particle lacking nucleic acids

Question 5

Which of the following is the most frequently used portal of entry for pathogens into the human body?

Accepted Answer

Mucous membranes of the respiratory tract

Question 6

A scientist is testing for the presence of catalase in a bacterial sample. Which type of test is being performed?

Accepted Answer

A biochemical test

Question 7

Which of the following statements about Gram-negative bacteria is correct?

Accepted Answer

They possess an outer membrane containing lipopolysaccharide (LPS).

Question 8

Which of the following best describes lysogeny?

Accepted Answer

The integration of a bacteriophage genome into the host bacterial chromosome

Question 9

A patient is prescribed a semisynthetic penicillin. Which of the following statements is true regarding its effect on eukaryotic cells?

Accepted Answer

Semisynthetic penicillins do not affect eukaryotic cells because they target peptidoglycan synthesis.

Question 10

Which of the following best explains how the overuse of antibiotics can lead to antibiotic resistance?

Accepted Answer

Overuse of antibiotics selects for bacteria with resistance genes, allowing them to survive and multiply.

Question 11

Which of the following is true about the genome of SARS-CoV-2 (Covid-19)?

Accepted Answer

It is composed of single-stranded RNA.

Question 12

Which of the following bacteria is gram-positive, facultative anaerobe, grows slowly as branching filaments, has a club shape, and is commonly found in the mouth of humans and animals?

Accepted Answer

Actinomyces

Question 13

Which of the following statements about viral spikes is correct?

Accepted Answer

Viral spikes can be found on both enveloped and non-enveloped viruses.

Question 14

Which of the following is the causative agent of stomach ulcers?

Accepted Answer

Helicobacter pylori

Question 15

A scientist is studying an infectious agent that consists only of a short piece of circular RNA and infects plants. What is this agent?

Accepted Answer

Viroid

Question 16

Which of the following statements about phage therapy is correct?

Accepted Answer

Phage therapy is an antibacterial treatment.

Question 17

Which of the following statements about endotoxins is correct?

Accepted Answer

Endotoxins are part of the lipopolysaccharide (LPS) layer of Gram-negative bacteria and can cause fever and shock.

Question 18

A new antibiotic is discovered that binds between adjacent G-C pairs in DNA. Which cellular process would this most likely affect?

Accepted Answer

Transcription

Question 19

Which of the following statements about viruses is correct?

Accepted Answer

Viruses are considered on the borderline between living and non-living because they require host cells to reproduce.

Question 20

Which of the following statements about Chlamydia trachomatis is correct?

Accepted Answer

It is a bacterium that causes sexually transmitted infections.

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