MICROANATOMY

Detailed explanation-1: -Once produced, araC acts as repressor by binding to the araI region to form a loop which prevents polymerases from binding to the promotor and transcribing the structural genes into proteins. In the absence of Arabinose and araC (repressor), loop formation is not initiated and structural gene expression will be lower.

Detailed explanation-2: -A repressor protein binding to the operator gene prevents the transcription of the structural genes for the operon in the absence of inducer.

Detailed explanation-3: -lac Repressor blocks transcribing RNA polymerase and terminates transcription.

Detailed explanation-4: -Gene expression in eukaryotic cells is regulated by repressors as well as by transcriptional activators. Like their prokaryotic counterparts, eukaryotic repressors bind to specific DNA sequences and inhibit transcription.