Negative/Positive Regulation in Operons vs Negative/Positive Feedback Loops

[shulace]

Cliff 4th ed Chapter 9 (molecular biology) classifies the trp operon (repressible) and the lac operon (inducible) as negative regulation, both of which use repressor proteins. Cliff's also classifies glucose repression (secondary regulatory process influencing lac operon) as positive regulation using an activator protein.

I'm struggling with the concept of the differences between negative regulation and positive regulation. Are the classifications based on whether or not it uses repressor proteins or activator proteins?

Also, what is the difference between a positive/negative regulation and a positive/negative feedback loops?

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[bluemoon27]

negative feedback if after you produce a substance, that newly produced protein will block something that lead to its formation in the pathway. This is a good thing if you have limited resources. Dont want the body to make too much in excess just enough of it.

positive feedback is after you produce a substance, that newly produced protein goes back in the pathway and leads to more product to form.

Hopefully my explanation gives you an overview, google it for additional details.