Water‑Soluble Messenger Processes (Three Pathways)

first step in the ion-channel pathway

first messenger binds surface receptor

what happens to the ion channel during Ion Channel pathway

it opens or closes

what changes inside the cell during Ion Channel pathway

ion movement to membrane potiential calcium levels change

final result of ion channel pathway

rapid cell response

What activates the receptor’s enzyme domain? in the enzyme-linked receptor process

first messenger binding

what enzyme is usually activated? in the enzyme-linked receptor process

tyrosine kinase

function of tyrosine kinase

phosphorylates docking proteins

what do phosphyrolated docking proteins trigger?

multiple intracellular signalling steps

final result for enzyme-linked receptor process

cell response (growth, metabolism)

1st step of GPCR Pathway

first messenger binds GPCR

what happens to the G protein

GDP to GTP swap activates the alpha subunit

what does the alpha subunit do

dissociates & activates an effector protein

what does the effector protein produce

second messengers (cAMP, IP₃, DAG, Ca²⁺).

what do 2nd messengers do

amplify the signal, trigger cell response