Question

Genes which code for transcription factors can have a large influence on gene expression. Mutations in genes that control gene expression can have large and sudden effects on the evolution of species. A protein that binds to a site on DNA next to a gene and blocks the transcription of that gene, thus preventing the synthesis of a protein that the gene encodes is known as a:

Answer 1

A protein that binds next to the gene and blocks the transcription of that gene thus preventing the sythesis of a protein that the gene encodes in called Repressor protein or repressor element.

Step-by-step explanation:

Repressor protein is a specific type of protein that binds to the specific site of target DNA molecule such as operator site thus blocking the expression of that gene.

For example Lac I gene of lac Operon encodes a repressor protein which in absence of lactose binds to the operator site of Lac Operon thus blocking the expression of 3 structural genes Lac Z,Lac Y and Lac A of Lac Operon.