Describe the active processes (i.e. involving activation and repression mechanisms) and passive processes (i.e. not involving activation and repression mechanisms) of quorum sensing in Vibrio fisheri.
What will be an ideal response?
The phenomenon of quorum sensing was first discovered in the bacteria that are able to produce light like fireflies (Vibrio fisheri). This system involves active control of an enzyme called luciferase, which is responsible for light emission, by the passive diffusion of autoinducers into (and out of) the bacterial cell.
LuxI is the protein that makes the autoinducer. For Vibrio fisheri, it makes an autoinducer that is an acyl homoserine lactone (AHL). Those passively diffuse out into the environment. When enough V. fisheri cells are in the same place, the density of AHLs goes way up. They then passively diffuse back into the cells and bind to the second protein luxR, which is an activator protein.
This is where the active part starts: LuxR helps the RNA polymerase complex bind to beginning of the lux operon, and all the lux genes get transcribed at a high level (inducer + activator protein). lux B and luxA genes encode luciferase. Luciferase generates a redox reaction in the cell that eventually leads to light formation.
You might also like to view...
A researcher discovers a new antibody. Upon evaluating its sequence, she determines that the antibody is not the result of genomic rearrangement alone. What other processes could have produced this specific antibody? Select all correct choices
A. germ cell hypomutation B. N-nucleotide addition C. alternative mRNA splicing D. somatic hypermutation
. Which of the following is one of the four major biological macromolecule classes?
a. proteases b. hydrophilic G-proteins c. nucleic acids d. amorphous solids
The organisms originally responsible for putting oxygen in Earth's atmosphere lived around
A) 3.5 million years ago. B) 3.5 billion years ago. C) 6 billion years ago. D) 1.5 million years ago. E) 2.4 billion years ago.
Book Principles of Geology, which Darwin read on board the HMS Beagle, argued in favor of which of the following concepts?
A) Earth's surface is shaped mainly by occasional catastrophic events. B) Meteorite impacts may have been a major cause of periodic mass extinctions. C) Earth's surface is shaped by natural forces that act gradually and are still acting. D) The processes that shape Earth today are very different from those that were at work in the past.