 Upstream and downstream (transduction)

In the context of molecular biology and cellular signaling, "upstream" and "downstream" refer to the orientation of signaling pathways, processes, or gene regulation. ### Upstream - **Definition**: Upstream elements refer to components or signals that occur or act before a particular point in a pathway or process. - **Context**: In signaling pathways, upstream refers to the initial receptors, ligands, or signaling molecules that activate or regulate downstream processes.