Hormone – biologically active molecule that is released into circulation from site of synthesis and acts at a distant sitecan be either hydrophilic (polypeptide hormone) or lipophilic (steroid) – biogenic amines can be eitherbinds specific receptor – on cell surface (hydrophilic hormones) or inside cell (lipophilic hormones)lipophilic hormones bind carrier proteins to travel in circulation; hydrophilic hormones travel freelycis-acting elements – DNA segments in the promoter region which bind trans-acting elementstrans-acting elements – molecules that impact downstream gene transcription when they bind cis-acting elements