3.B.2 

      In gene regulation, the regulatory genes control to transcription of genes. Operons will be the main area of gene regulation in DNA. Repressors will bind to the operator region to prevent transcription. Promoters will begin transcription with the use of inducers all the way to the terminator. Activators will begin transcription in the enhancer region. The trip operon codes for a tryptophan, a amino acid. When there is too much tryptophan in the cell, the operon will become a repressible operon The Lac operon allows RNA polymerase by becoming a inducible operon. Eukaryotes use transcription factors to regulate genes.

      Gene regulation is involved in a number of cells with signal transmission. Cytokine signal for when cyclin must be produced during the cell cycle. In Seed germination, gibberellin signals seedling. Morphogens assist in appoint stem cells into different cell types. The P53 gene can cause disruptions in cell division if mutated or damaged.