Question 1

Which of the following best describes the main ecological role of cyanobacteria in Earth's history?

Accepted Answer

They significantly increased the oxygen content of the atmosphere through oxygenic photosynthesis.

Question 2

A patient presents with a severe wound infection after a hospital stay. The causative agent is a Gram-negative, metabolically diverse bacterium with polar flagella, commonly found in soil and water. Which organism is most likely responsible?

Accepted Answer

Pseudomonas aeruginosa

Question 3

Which of the following statements about the lysogenic cycle of bacteriophage lambda is correct?

Accepted Answer

The phage DNA integrates into the host genome and is replicated along with it as a prophage.

Question 4

Which of the following fungi is used in the production of bread, wine, and the hepatitis B vaccine?

Accepted Answer

Saccharomyces cerevisiae

Question 5

A Gram-positive bacterium with a high G+C content, acid-fast cell wall, and slow growth rate is most likely:

Accepted Answer

Mycobacterium tuberculosis

Question 6

Which of the following best explains why viruses are considered obligate intracellular parasites?

Accepted Answer

They require living host cells to multiply because they lack ribosomes and ATP-generating mechanisms.

Question 7

Which of the following is a correct description of the structure and function of a fungal mycelium?

Accepted Answer

A mass of hyphae that forms the vegetative body of a fungus, responsible for nutrient absorption.

Question 8

Which of the following equations correctly represents the process of nitrogen fixation by bacteria such as Azospirillum and Rhizobium?

Accepted Answer

$$\mathrm{N_2$ + 8H^+ + 8e^- + 16ATP \rightarrow 2NH_3 + H_2$ + 16ADP + 16P_i}$$

Question 9

A patient is diagnosed with malaria. Which of the following best describes the life cycle of Plasmodium in the human host?

Accepted Answer

Sporozoites infect liver cells, undergo schizogony, and merozoites infect red blood cells, forming ring stages.

Question 10

Which of the following is a distinguishing feature of the cell wall of Mycobacterium species?

Accepted Answer

It contains a thick layer of mycolic acids, making it waxy and water-resistant.

Question 11

Which of the following best describes the function of the viral envelope?

Accepted Answer

It is a lipid, protein, and carbohydrate layer derived from the host cell membrane, aiding in attachment and entry.

Question 12

Which of the following is a correct statement about the economic importance of algae?

Accepted Answer

Brown algae are harvested for algin, a thickener used in foods.

Question 13

A patient presents with symptoms of whooping cough. Which Gram-negative, nonmotile rod is the most likely causative agent?

Accepted Answer

Bordetella pertussis

Question 14

Which of the following best explains why prion diseases are difficult to treat and control?

Accepted Answer

Prions are resistant to standard sterilization procedures because they lack nucleic acids and are misfolded proteins.

Question 15

Which of the following best describes the difference between a lytic and a lysogenic bacteriophage infection?

Accepted Answer

Lytic infection results in immediate lysis of the host cell, while lysogenic infection involves integration of phage DNA into the host genome without immediate lysis.

Question 16

Which of the following is a correct statement about the structure of a typical virus?

Accepted Answer

It contains either DNA or RNA, but never both, surrounded by a protein capsid.

Question 17

Which of the following is a correct description of the role of arthropods in the transmission of microbial diseases?

Accepted Answer

They act as vectors, transmitting pathogens via mechanical or biological transmission.

Question 18

Which of the following best describes the process of specialized transduction in bacteria?

Accepted Answer

A lysogenic phage transfers specific bacterial genes to another bacterium via a prophage.

Question 19

Which of the following is a correct statement about the reproduction of fungi?

Accepted Answer

Fungi reproduce both sexually and asexually via the formation of spores.

Study Notes: Classification and Diversity of Microorganisms (Bacteria, Archaea, Fungi, Algae, Protozoa, Helminths, Viruses, Viroids, and Prions)

Study Guide - Practice Questions

Study Guide - Flashcards