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A simple negative feedback system is descriptive, for example, of some electronic amplifiers. The feedback is negative if the loop gain AB is negative.. Negative feedback (or balancing feedback) occurs when some function of the output of a system, process, or mechanism is fed back in a manner that tends to reduce the fluctuations in the output, whether caused by changes in the input or by ...
A negative feedback loop is also known as a balancing loop, and it may be common to see oscillations in which a delayed negative feedback signal is used to maintain homeostatic balance in the system. [1] Feedback loops can be used for amplification (positive) or self-correction (negative). The right combination of positive and negative feedback ...
The CLAW hypothesis proposes a negative feedback loop that operates between ocean ecosystems and the Earth's climate. [1] The hypothesis specifically proposes that particular phytoplankton that produce dimethyl sulfide are responsive to variations in climate forcing, and that these responses act to stabilise the temperature of the Earth's atmosphere.
This is an example of a locally acting (negative feedback) mechanism. An example of upregulation is the response of liver cells exposed to such xenobiotic molecules as dioxin. In this situation, the cells increase their production of cytochrome P450 enzymes, which in turn increases degradation of these dioxin molecules.
The same principles of negative feedback control (including the ability to nullify effects of unpredictable external or internal disturbances) apply to living control systems. [4] Implications of these principle are e.g. intensively studied by biological and medical cybernetics and systems biology.
Attenuation is a second mechanism of negative feedback in the trp operon. While the TrpR repressor decreases transcription by a factor of 70, attenuation can further decrease it by a factor of 10, thus allowing accumulated repression of about 700-fold. Attenuation is made possible by the fact that in prokaryotes (which have no nucleus), the ...
The balance of nature, also known as ecological balance, is a theory that proposes that ecological systems are usually in a stable equilibrium or homeostasis, which is to say that a small change (the size of a particular population, for example) will be corrected by some negative feedback that will bring the parameter back to its original "point of balance" with the rest of the system.
The trp operon additionally uses attenuation to control expression of the operon, a second negative feedback control mechanism. The trp operon is well-studied and is commonly used as an example of gene regulation in bacteria alongside the lac operon .