Question 1

Which of the following structures is found in all bacteria and is essential for maintaining cell shape and preventing lysis due to osmotic pressure?

Accepted Answer

Cell wall

Question 2

A bacterium is observed to move toward a glucose source. Which term best describes this behavior, and what is the underlying mechanism?

Accepted Answer

Positive chemotaxis; flagella rotate counterclockwise causing a run toward the attractant

Question 3

Which of the following best describes the composition and function of the bacterial glycocalyx capsule?

Accepted Answer

Composed of repeating polysaccharide units; protects against phagocytosis

Question 4

A clinical isolate is found to be resistant to boiling, drying, and many disinfectants. Which structure is most likely responsible for this resistance?

Accepted Answer

Endospore

Question 5

Which of the following statements about gram-negative bacteria is CORRECT?

Accepted Answer

They possess an outer membrane containing lipopolysaccharide (LPS), which can act as an endotoxin

Question 6

Which of the following is a function of bacterial plasmids?

Accepted Answer

Confer protective traits such as antibiotic resistance

Question 7

A bacterium is described as 'pleomorphic.' What does this mean?

Accepted Answer

It can vary in size and shape due to genetic or nutritional differences

Question 8

Which of the following best explains why Mycobacterium tuberculosis is resistant to many chemicals and dyes?

Accepted Answer

Its cell wall contains mycolic acid, a long-chain fatty acid

Question 9

Which of the following appendages is used primarily for the transfer of DNA between bacterial cells?

Accepted Answer

Pilus

Question 10

Which of the following is NOT a typical function of the bacterial cytoplasmic membrane?

Accepted Answer

Protein synthesis

Question 11

A patient presents with a wound infection caused by a bacterium that forms chains of rod-shaped cells. Which term best describes this arrangement?

Accepted Answer

Streptobacilli

Question 12

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

Accepted Answer

Unique membrane lipids and lack of true peptidoglycan

Question 13

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

Accepted Answer

Induced by nutrient depletion, leading to the formation of a resistant endospore

Question 14

Which of the following is a medically significant consequence of bacterial biofilm formation?

Accepted Answer

Protection of bacteria from host immune responses and disinfectants

Question 15

Which of the following best describes the function of porin proteins in the outer membrane of gram-negative bacteria?

Accepted Answer

Allow selective passage of small molecules

Question 16

Which of the following is the correct order of steps in the Gram stain procedure?

Accepted Answer

Crystal violet, Gram’s iodine, alcohol, safranin

Question 17

Which of the following is a correct match between a bacterial group and its cell wall characteristic?

Accepted Answer

Gracilicutes: gram-negative cell wall

Question 18

Which of the following is the best definition of a bacterial species?

Accepted Answer

A collection of bacterial cells that share an overall pattern of similar traits

Question 19

Which of the following is a function of teichoic acids in gram-positive bacteria?

Accepted Answer

Cell wall maintenance and enlargement during cell division

Question 20

A bacterium isolated from a hot spring grows optimally at 90°C and cannot grow below 50°C. Which term best describes this organism?

Accepted Answer

Hyperthermophile

Chapter 4: Bacteria and Archaea: Structure, Function, and Classification- Book Notes

Guida di studio - Domande di pratica

Study guide - Flashcard