BIOL 318 Lecture Notes - Lecture 36: Ribonuclease, Operon, Catabolism
4 Jul 2016
School
Department
Course
Professor
Document Summary
A cell must monitor two compartments in order to know when to alter gene expression and adjust its physiology: the cytoplasm within the cell and the environment outside. Intracellularly, the concentrations of vitamins, amino acids, and nucleotides must be sufficient and balanced to supply the biosynthetic and energetic needs of the cell. To achieve balance, the cell must control de novo (new) synthesis of these compounds and know what carbon and energy sources are present in order to assemble the proper catabolic pathway. Sensing conditions within the cell is relatively straightforward. Regulatory proteins bind specific small-molecular-weight compounds called ligands. The ligand, once bound, then alters the ability of the regulatory protein to latch onto specific. Dna regulatory sequences located near the promoters of target genes. Regulatory proteins come in two forms: repressors and activators (not to be confused with activator sequences). Repression - repressor proteins bind to regulator sequences and prevent the transcription of target genes.
