Question 1

Which of the following best describes a microbial biofilm?

Accepted Answer

A collection of microbes living on a surface in a complex community, often embedded in a self-produced matrix.

Question 2

Which process allows bacteria within a biofilm to coordinate their activities and behave as a community?

Accepted Answer

Quorum sensing

Question 3

Why are biofilms often more resistant to antimicrobial agents than planktonic (free-living) bacteria?

Accepted Answer

The extracellular matrix and close community structure protect bacteria from harmful agents.

Question 4

Which of the following is a real-world example of a biofilm causing a problem in a medical setting?

Accepted Answer

Biofilm formation on catheters leading to persistent infections.

Question 5

Which of the following statements about colonies and biofilms is correct?

Accepted Answer

A colony arises from a single parent cell, while a biofilm is a community of microbes living on a surface.

Question 6

Which of the following is NOT a function of the extracellular matrix in a biofilm?

Accepted Answer

Increasing the rate of binary fission in individual cells.

Question 7

A patient develops a persistent infection on a heart valve after surgery. Which property of biofilms most likely contributes to the difficulty in treating this infection?

Accepted Answer

Biofilms can shelter bacteria from both antibiotics and immune responses.

Question 8

Which of the following best explains why biofilms are commonly found in natural environments?

Accepted Answer

Biofilms allow bacteria to survive harsh conditions by providing protection and facilitating nutrient sharing.

Question 9

Which of the following is a key step in the initial formation of a biofilm?

Accepted Answer

Bacteria attach to a surface and produce an extracellular matrix.

Question 10

Which of the following statements about quorum sensing in biofilms is TRUE?

Accepted Answer

Quorum sensing is a process by which bacteria detect and respond to population density by gene regulation.

Question 11

A researcher observes that bacteria in a biofilm are able to survive exposure to an antibiotic that kills the same species in planktonic form. Which mechanism best explains this observation?

Accepted Answer

The biofilm's extracellular matrix limits antibiotic penetration and facilitates the exchange of resistance genes.

Question 12

Which of the following is NOT a typical location where biofilms are found?

Accepted Answer

Sterile surgical instruments immediately after autoclaving.

Question 13

Which of the following best describes the role of water currents in biofilm structure?

Accepted Answer

They help distribute nutrients and remove waste products within the biofilm.

Question 14

Which of the following is a major reason why biofilms are important in the environment?

Accepted Answer

They dominate the structure of most natural environments and facilitate nutrient cycling.

Question 15

Which of the following is a correct sequence of events in biofilm development?

Accepted Answer

Attachment, matrix production, quorum sensing, detachment.

Microbial Nutrition and Growth: Colonies, Biofilms, and Environmental Requirements

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