AP BIOLOGY

Detailed explanation-1: -In molecular genetics, a repressor is a DNA-or RNA-binding protein that inhibits the expression of one or more genes by binding to the operator or associated silencers. A DNA-binding repressor blocks the attachment of RNA polymerase to the promoter, thus preventing transcription of the genes into messenger RNA.

Detailed explanation-2: -Repressor proteins can be DNA– or RNA-binding: DNA-binding repressors – block the binding of RNA polymerase to the promoter. As a result, the gene is prevented from being transcribed into mRNA. RNA-binding repressors – bind to mRNA, preventing protein translation.

Detailed explanation-3: -Binding of repressor to operator prevents the binding of RNA polymerase at promoter sequence, thereby not allowing gene expression.

Detailed explanation-4: -An operator is a segment of DNA adjacent to a gene; a repressor is. a protein that binds to the operator and controls the expression of. the gene.

Detailed explanation-5: -Repressor binding blocks RNA polymerase from binding with the promoter, thereby leading to repression of operon gene expression.