Question 1

Which of the following best describes the main advantage of biofilm formation for bacteria in a medical context, such as on a catheter or implant?

Accepted Answer

Biofilms provide a protective matrix that increases resistance to antibiotics and immune responses.

Question 2

During which stage of the biofilm life cycle are bacteria most easily removed by rinsing or light cleaning?

Accepted Answer

Initial Attachment (Reversible)

Question 3

A patient with cystic fibrosis develops a chronic lung infection. Which property of biofilms most contributes to the persistence of this infection?

Accepted Answer

Biofilms allow bacteria to evade immune responses and resist antibiotics.

Question 4

Which of the following chemical signals is primarily used by Gram-negative bacteria for quorum sensing?

Accepted Answer

Acyl-homoserine lactones (AHLs)

Question 5

What is the main function of persister cells within a mature biofilm?

Accepted Answer

To enter a dormant state, increasing resistance to antibiotics and harsh conditions.

Question 6

Which of the following best explains why synthetic fabrics like polyester are more prone to 'permastink' compared to cotton?

Accepted Answer

Polyester traps oils and provides microscopic spaces for biofilm formation.

Question 7

A researcher wants to disrupt bacterial communication in a mixed-species biofilm. Which signaling molecule should they target to affect both Gram-positive and Gram-negative bacteria?

Accepted Answer

AI-2 (Autoinducer-2)

Question 8

Which of the following is a correct sequence of the biofilm life cycle stages?

Accepted Answer

Initial attachment → Irreversible adhesion → Maturation I → Maturation II → Dispersion

Question 9

Which of the following best describes the role of quorum sensing in biofilm formation?

Accepted Answer

It coordinates gene expression and group behaviors once a threshold cell density is reached.

Question 10

A hospital is experiencing recurring infections on catheters despite regular cleaning. Which property of biofilms most likely explains this phenomenon?

Accepted Answer

Biofilms can form a protective matrix that resists removal and antibiotic treatment.

Question 11

Which of the following strategies is an example of quorum quenching?

Accepted Answer

Applying enzymes that degrade signaling molecules to disrupt bacterial communication.

Question 12

In the context of Pseudomonas aeruginosa, which quorum sensing system is considered the 'master regulator' and typically activates the others?

Accepted Answer

Las system

Question 13

Which of the following equations best represents the positive feedback loop in quorum sensing, where $$S is $$the concentration of signaling molecules and $$N is $$the number of bacteria?

Accepted Answer

$$\frac{dS}{dt} = aN + bS$$

Question 14

A patient presents with a chronic wound infection that does not respond to standard antibiotics. Which combination of treatments is most likely to be effective against a biofilm-forming pathogen like Pseudomonas aeruginosa?

Accepted Answer

Physical removal of the biofilm, enzymatic disruption, and combination antibiotics.

Question 15

Which of the following is a real-world example of a beneficial biofilm in the human body?

Accepted Answer

Lactobacilli biofilms in the vagina preventing harmful microbes from growing.

Question 16

Which of the following best explains why regular detergents often fail to remove 'permastink' from synthetic fabrics?

Accepted Answer

Detergents cannot break down the sticky biofilm matrix that protects odor-causing bacteria.

Question 17

Which of the following is NOT a function coordinated by quorum sensing in bacterial biofilms?

Accepted Answer

DNA replication during cell division

Question 18

A new laundry product claims to eliminate 'permastink' by using enzymes. What is the most likely mechanism by which these enzymes work?

Accepted Answer

They break down the biofilm matrix, allowing detergents to remove bacteria and residues.

Question 19

Which of the following best describes the division of labor in a mature biofilm?

Accepted Answer

Cells differentiate into roles such as matrix producers, persister cells, and disperser cells based on their position and local environment.

Question 20

Which of the following is a correct statement about the role of water channels in mature biofilms?

Accepted Answer

They provide pathways for nutrients and oxygen to reach cells and for waste removal.

Biofilms: Structure, Life Cycle, and Clinical Significance

Study Guide - Practice Questions

Study Guide - Flashcards