Question

Which of the following best describes what occurs as the density of a QS bacterial population increases?

a) The concentration of QS signaling molecules decreases, eventually triggering a change in gene expression throughout the bacterial population.
b) The concentration of QS signaling molecules increases, eventually triggering a change in gene expression in a few members of the bacterial population.
c) The concentration of QS signaling molecules decreases, eventually triggering a change in gene expression in a few members of the bacterial population.
d) The concentration of QS signaling molecules increases, eventually triggering a change in gene expression throughout the bacterial population.

Please choose the most appropriate answer.

Answer 1

The correct answer is d) The concentration of QS signaling molecules increases, causing changes in gene expression throughout the population. This process of quorum sensing allows bacteria to coordinate activities like virulence and biofilm formation when a critical density is reached.

Step-by-step explanation:

When considering what occurs as the density of a QS bacterial population increases, the correct answer is d) The concentration of QS signaling molecules increases, eventually triggering a change in gene expression throughout the bacterial population. This phenomenon, known as quorum sensing (QS), involves bacteria producing and releasing chemical signals, known as autoinducers, to detect the population density and consequently regulate gene expression. As bacterial density increases, the concentration of signaling molecules also increases. When these molecules reach a threshold concentration, they bind to specific receptors, triggering a cascade of signaling events that lead to changes in gene expression. This cooperative behavior among bacterial cells can initiate various group behaviors such as bioluminescence, virulence factor production, biofilm formation, and more.