cell communication

endocrine

movment of hormones through bloodstream across long distances

paracrine

relies on diffusion over short distances

autocrine

cell signals itself

juxtacrine

communicates through direct contact, plasmodesmata or gap junctions

steps of cell communcication

cell is stimulated, cell sends ligands to receptor protein, signal transduction pathway, response

hydrophillic receptors

rapid short lived, g protein coupled recept, receptor protein kinase, ligand gated ion channel

hydrophobic signals

slow long lived, intracellular receptor protein

secondary messangers

molecules that relay signals recieved from receptor to effector proteins

repressible operon

typically on, but can be inhibited in the presence of a molecule

inducible operon

typically off, but activated by presence of a specific molecule