A feedback loop is a biological event in which the output of a system amplifies the system (positive feedback) or inhibits the system (negative feedback). Living organisms are able to maintain homeostasis through these feedback loops. This is the mechanism that allows us to keep our internal environment relatively constant. Examples of negative feedback include maintaining blood glucose levels, maintaining body temperature, maintaining blood pH, etc. When a change occurs in the body (i.e. the blood glucose level increases), the nervous system detects the change and stimulates an antidote hormonal response. . While examples of positive feedback include the production of the hormone oxytocin during the birth of the baby. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay The difference between positive and negative feedback is their response to change: positive feedback amplifies change while negative feedback reduces change. This means that positive feedback will result in more of one product: more contractions or more coagulated platelets. While negative feedback will result in an inferior product: less heat, less pressure or less salt. Positive feedback moves away from a target point while negative feedback moves towards a target. In feedback control, the system outputs are measured and if they do not match the desired output, the controlled parameter is adjusted again. If the input does not change, these differences usually result from noise. The controller receives feedback from the system's output that quantifies its deviation from the desired state, regardless of what causes this difference. Feedback control is, for example, of a metabolic pathway by a metabolite of the pathway acting in the opposite direction to the metabolism flow, i.e. upstream or "earlier" in the pathway. In feedforward control, disturbances are measured and the controlled parameter is calculated based on a logic model. There is no feedback to see whether the system is actually in the desired state or whether it has significantly deviated from the desired state. If unmeasured disturbances cause the system outputs to differ from those desired, the controller will not react. Feedforward control is, for example, of a metabolic pathway by a metabolite of the pathway acting in the same direction as the metabolic flux, i.e. downstream or "later" in the pathway, for example the activation of pyruvate kinase by fructose 1,6- bisphosphate. Briefly explain the differences between negative control and positive control with suitable examples. The positive control is an experimental control that gives a positive result. It does not have the independent variable tested by the researcher. However, it shows the desired effect expected from the independent variable. The positive control is a useful test to demonstrate that the protocols, reagents and equipment are working well without errors. If experimental errors occur, the positive control will not produce the correct result. In contrast, the negative control does not give a response to treatment. In experiments, the negative control should be designed in such a way that it does not produce the desired outcome of the experiment. Controls are essential elements of an experiment. Scientific experiments include them to eliminate experimental errors and biases. The results of the control experiments are useful for a validated statistical analysis of the experiment. Therefore the reliability of the experiment can be increased by means of control treatments. In the example where the toxicity of a substance is tested, the positive control would be.