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Chapter 9: Problem 19

The bio luminescent bacteria Vibrio fischeri produces luminescence only if the population reaches a certain density. What is the advantage of an auto inducer? a. An auto inducer allows the producer to act independently of the presence of other cells. b. An auto inducer does not diffuse away from the cell. c. An auto inducer allows a positive feedback loop, which increases the response in proportion to the population size. d. An auto inducer presents no advantage for the cell.

Short Answer

Expert verified
c. An auto inducer allows a positive feedback loop, which increases the response in proportion to the population size.

Step by step solution

01

Understand the concept of a bio luminescent bacteria

Bio luminescent bacteria, like Vibrio fischeri, produce light through a specific biochemical process. This luminescence generally occurs when the bacterial population reaches a certain density, which is detected through quorum sensing.
02

Define an auto inducer

An auto inducer is a chemical signal produced by bacteria that increases in concentration as a function of cell density. When a certain threshold concentration is reached, it triggers a response in the bacteria, often through a positive feedback loop.
03

Analyze option (a)

Option (a) states that an auto inducer allows the producer to act independently of the presence of other cells. This is incorrect because the function of an auto inducer is to gauge the density of the population, not to act independently of it.
04

Analyze option (b)

Option (b) states that an auto inducer does not diffuse away from the cell. This statement is incorrect as auto inducers generally diffuse through the environment to interact with other cells.
05

Analyze option (c)

Option (c) states that an auto inducer allows a positive feedback loop, which increases the response in proportion to the population size. This statement is correct because as the population grows, more auto inducer is produced, which in turn triggers more luminescence.
06

Analyze option (d)

Option (d) states that an auto inducer presents no advantage for the cell. This is incorrect because the auto inducer facilitates an important quorum sensing mechanism.
07

Conclude the correct option

Based on the analysis of the options, the correct answer is (c). The auto inducer allows a positive feedback loop, which increases the response in proportion to the population size.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

bio luminescent bacteria
Bio luminescent bacteria, such as *Vibrio fischeri*, have the fascinating ability to produce light through a biochemical process called bioluminescence. This phenomenon often occurs when the population of these bacteria reaches a certain density. This ability is not just for show鈥攊t's a critical part of their survival strategy. These bacteria use a communication system called quorum sensing to detect when the population has reached a specific threshold. When this density is achieved, the bacteria collectively turn on their bioluminescent capabilities.
auto inducer
An auto inducer is a chemical signal produced by bacteria that plays a crucial role in quorum sensing. The concentration of this signal increases as a function of cell density. Here's how it works:
  • As bacteria grow and multiply, they release auto inducers into their environment.
  • When the concentration of auto inducers reaches a certain threshold, it triggers a response from the bacterial cells.
  • This response can include changes in gene expression, leading to behaviors like bioluminescence.
Auto inducers are essential for bacteria to coordinate their actions, ensuring that certain behaviors only occur when they are most beneficial.
positive feedback loop
A positive feedback loop in the context of auto inducers is a mechanism where the presence of an auto inducer results in the increased production of that same inducer. This creates a loop that amplifies the response: As the population grows, more auto inducer is produced, which in turn leads to an even greater response. This is crucial for bacteria like *Vibrio fischeri* because:
  • It ensures that bioluminescence is only turned on when a sufficient population density is reached.
  • This collective behavior can be advantageous for attracting hosts or deterring predators.
  • The positive feedback loop efficiently coordinates complex group behaviors that would be impossible for individual bacteria to achieve alone.
This process of amplification ensures a strong, communal response that is finely tuned to the density of the bacterial population.

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Most popular questions from this chapter

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