Module 6 Flashcards
Define Signal Transduction
how the body communcates messages to eliciate responses in cell or tissue
Classes of xcellular messengers/signals and what length they travel
Hormones (distance)
Growth Factors (vaious distances)
Neurotransmitters (short)
Pheromones (secreted by one but acted upon another)
How are signals amplied
Through signal transfuction. Signals start small but amplify through signal transduction
Types of hormones and examples
Steroids (estrogen/VitD)
Proteins (HGF)
AA derivatives (epinipherine or thyroxine)
Peptides (insulin or glucagon)
How do hormones work. Give 3 examples
Secreted by endocrine glands, travel through bloodstream, bind to specific receptors
Ex. - Epinephrine, glucagon and insulin which all act as signal molecules
What are the components of signal transduction and explain shortly
Reception - of x-cellular signal
Transduction - signal from outside to inside of cell
Cellular response - response to signal
Reception. Explain it w/ example regarding epinepherine
Hormones act on their target cells by binding to receptors
Hormones and signal molecules AKA ligands
Once signal is received signal must be transduced
Ex. Epinepherine binds to B adreneric receptor which is a transmembrane protein to which epinephrine binds.
What type of a receptor is the B adgenric receptor
Transmembrane G protein coupled receptor
Transduction w/ Example of Epinephrine
Epinephrine transducer is a G protein
G protein is hetrotrimeric w/ Alpha, Beta and Gamma subunits
- Receptor + Hormone causes conformational change in receptor promoting interaction w/ G protein
- G protein + Receptor + Hormone = G protein to exchange GDP for GTP
- GDP bound to G protein = inactive
- GTP bound to G protein = Active
Active G protein disassociated from its subunits and receptor
- Active G protein activates effector, an enzyme called adenylate cyclase to elicit cellular response
Cellular Response Part 1 - Epinephrine
G protein interact w/ adenylate cyclase
Adenylate cyclase catalyzes ATP and cAMP
cAMP is a secondary messenger
Cellular Response Part 2 - Epinepherine
cAMP binds to cAMP dependent kinase A and phosphorylates it ~ activating it
Kinase A interacts with Kinase B, phosphorylation and activating it
Kinase B interacts with glygogen phosphorylase ~ phosphorylation and activating it
Glycogen phosphorylase a catalyzes breakdown of glugogen, releasing glucose 1 phosphate for degradation and ATP production
Over all signal transduction pathway of epinepherine
- Reception: The signal was epinephrine. The signal was received when it bound to the beta adrenergic receptor
- Transduction: the signal was transduced by the G protein
- Cell response:
Signal tranduction of Insulin
- Insulin receptor is a tyrosine kinase family receptor
- Tysosine Kinase family receptors have a domain that is activated due to signal/ligand reception
1) Reception: insulin is the signal, binds to its receptor,
2) Transduction: receptor activates tyrosine kinase activity resulting in cascade by which PIP3, a secondary messenger is synthesized
2) GLUT4 or glucose transporter 4 proteins are relocated from cytosol to plasma membrane and responsible for taking for taking up glucose
What are the two Glycogen phosphorylase
a = phosphoylated active b = dephosphorylated inactive form
What is energy metabolism
Pathway in generating or storing metabolic energy
