Question 1

Which of the following statements best describes the relationship between human and bacterial cells in the typical adult human body?

Accepted Answer

The number of bacterial cells is roughly equal to the number of human cells, but if red blood cells are excluded, bacteria outnumber human cells by about 10 to 1.

Question 2

Which of the following is NOT a correct statement about the global impact of infectious diseases?

Accepted Answer

The majority of deaths worldwide are now caused by infectious diseases rather than chronic diseases.

Question 3

Which of the following best defines an 'emerging infection'?

Accepted Answer

A new, reemerging, or drug-resistant infection whose incidence in humans has increased within the past two decades or threatens to increase soon.

Question 4

Which of the following is a correct pairing of a microbe and a disease it causes?

Accepted Answer

Trypanosoma brucei – African sleeping sickness

Question 5

Which of the following characteristics is unique to Archaea compared to Bacteria?

Accepted Answer

Cell membranes can be monolayers made with isoprenoid fatty acids.

Question 6

Which of the following is a correct statement about the classification of microorganisms?

Accepted Answer

Fungi, protozoa, and algae are all eukaryotic microorganisms.

Question 7

A patient presents with a severe diarrheal illness after drinking contaminated water. Which protozoan is most likely responsible, and what is its primary mode of motility?

Accepted Answer

Entamoeba histolytica; pseudopodia

Question 8

Which of the following best explains why the conquest of microbial diseases was believed to be imminent in the 1960s?

Accepted Answer

The development of antibiotics and vaccines led to a dramatic decrease in infectious disease mortality.

Question 9

Which of the following is a distinguishing feature of fungi compared to bacteria?

Accepted Answer

Fungi are eukaryotic and obtain food from other organisms.

Question 10

Which of the following is a correct statement about bacteriophages?

Accepted Answer

Bacteriophages are viruses that infect bacteria and are more numerous than any other organism on Earth.

Question 11

Which of the following best describes the role of fungi as decomposers in the environment?

Accepted Answer

Fungi break down organic matter, recycling nutrients such as carbon and nitrogen.

Question 12

Which of the following is NOT a correct statement about algae?

Accepted Answer

Algae are classified as prokaryotes.

Question 13

A scientist is classifying a microorganism that is unicellular, lacks a nucleus, and has a cell wall containing peptidoglycan. To which group does this organism most likely belong?

Accepted Answer

Bacteria

Question 14

Which of the following is a correct statement about the three-domain system proposed by Woese?

Accepted Answer

It is based on differences in 16S ribosomal RNA sequences.

Question 15

Which of the following is a real-world example of an emerging infectious disease?

Accepted Answer

Ebola outbreak in West Africa

Question 16

Which of the following equations best represents the ratio of bacterial to human cells in the adult human body (excluding red blood cells)?

Accepted Answer

$$10:1$$

Question 17

Which of the following is a correct statement about protozoa?

Accepted Answer

Protozoa are single-celled eukaryotes that can move using pseudopodia, cilia, or flagella.

Question 18

Which of the following is a correct statement about the composition of prokaryotic cell walls?

Accepted Answer

Bacterial cell walls contain peptidoglycan, while archaeal cell walls are composed of polymers other than peptidoglycan.

Question 19

A patient is diagnosed with a fungal infection. Which of the following features would help distinguish the causative organism from bacteria under a microscope?

Accepted Answer

Presence of a nucleus and chitin in the cell wall

Question 20

Which of the following best explains why microbial diseases reemerged in the late 20th century after a period of decline?

Accepted Answer

The evolution of drug-resistant strains and the emergence of new pathogens led to an increase in infectious diseases.

Introduction to Microbiology: Microorganisms, Infectious Diseases, and Classification

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