cell communication Flashcards
animal cells communicate by:
same cell
direct contact
local distance
long distance
same cell communication
autocrine
some cancer cells release their own growth hormone
direct contact cell communication
juxtacrine
gap junctions
plasmodesmata
local distance cell communication
paracrine
growth factors, neurotransmitters
long distance cell communication
endocrine
hormones
3 stages of cell signaling
reception
transduction
response
reception
detection of a signal molecule (ligand) coming from outside the cell
transduction
convert signal to a form that can bring about a cellular response
response
cellular response to the signal molecule
binding in reception
between signal molecule (ligand) and receptor
HIGHLY SPECIFIC
2 types of receptors
plasma membrane receptor
intracellular receptors
plasma membrane receptors are
water-soluble ligands
intracellular receptors are
in the cytoplasm, nucleus?
hydrophobic or small ligands
3 steps in reception
ligand binds to receptor protein
protein changes shape
initiates transduction signal
3 types of plasma membrane receptors
g-protein coupled receptors (GPCR)
tyrosine kinase
ligand-gated ion channels
GPCR
7 transmembrane segments in membrane
G protein + GTP activates enzyme, triggers cell response
tyrosine kinase
attaches (P) to tyrosine
activates multiple cellular responses at once
ligand-gated ion channels
signal receptor changes shape
regulates flow of specific ions (Ca2+, Na+)
function of transduction
cascades of molecular interactions relay signals from receptors to target molecules
protein kinase
enzyme that phosphorylates and activates proteins at next level in transduction
what happens when protein kinase phosphorylates
Attached a phosphate group (PO4) to a protein to activate
Only 3 amino acids can be phosphorylated- Threonine (Thr), Serine (Ser), and Tyrosine (Tyr)
purpose of phosphorylation cascade
enhance and amplify signal
second messengers
small, non-protein molecules or ions that can relay signal inside cell
cAMP
cyclic adenosine monophosphate