communication and signalling Flashcards
what do multicellular organisms signal between?
cells using extracellular signalling molecules
describe receptor molecules of target cells?
proteins with a binding site for a specific signal molecule
what does binding change?
the conformation of the receptor, initiates a response within the cell
why do different cell types produce specific signals?
because they can only be detected and responded to by cells with the specific receptor
what is signal transduction?
transmembrane proteins
convert an extracellular signal to a specific intracellular signal
what can hydrophobic signalling do?
pass through membranes, receptor molecules so it can be within the nucleus
It can directly influence transcription of genes
what is an example of hydrophobic signalling
thyroxine and steroid hormones
what do transduced hydrophilic signals often involve?
g proteins or cascades of phosphorylation by kinase enzymes
what does phosphorylation cascades allow?
more than one intracellular signalling pathway to be activated
what does binding of the peptide hormone insulin to its receptor result in?
intracellular signalling cascade that triggers the recruitment of GLUT 4
what does exercise in type 2 diabetes trigger?
recruitment of Glut4 it can improve uptake of glucose to fat and muscle cells
why do hydrophobic signalling molecules diffuse diffuse through the phospholipid bilayer?
so it can bind to intracellular receptors
Why in multicellular organism do only target cells respond to a specific signal?
only target cells have receptor molecules for the signalling molecule
what os type 1 caused by?
insufficient production of insulin
