In the absence of tryptophan, what happens to the genes within the trp operon? a) the regulator without tryptophan-binding prevents the genes from being transcribed. b) the regulator falls off the operator and structural genes get transcribed. c) lack of tryptophan increases the level of camp high, which leads to activation of cap protein and gene expression. d) the active repressor binds to the operator and genes do not get transcribed. e) the active activator binds to the operator and transcription of structural gene takes place.

The correct answer is option b) "The regulator falls off the operator and structural genes get transcribed".

Explanation:

The trp operon is a group of genes that expresses the components for production of tryptophan. Tryptophan works as a regulator of the operon's function, therefore at low levels is activated and at high levels is silenced. In the absence of tryptophan, the regulator falls off the operator and structural genes get transcribed.

did you fail the test? xd

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.