BIO 225 CORRECT EXAMS SCRIPT LATEST
QUESTIONS AND ANSWERS SURE A+
✔✔what types of hormones use cytosolic receptors w/ examples. how does it work -
✔✔hydrophobic hormones
ex. thyroid hormones, steroid hormones
ligand passes through membrane
bind to receptor in cytoplasm or nucleus
ligand-receptor complex binds to DNA sequence
recruits other transcription factors to target genes
can alter production of specific mRNAs or trigger a cascade
✔✔what types of hormones use transmembrane receptors - ✔✔hydrophilic
peptide hormones
most amine hormones
✔✔describe receptor guanylate cyclase - ✔✔ligand binds
change in receptor conformation
activates guanylate cyclase
converts GTP to cGMP (second messenger)
cGMP activates PKG
PKG phosphorylates target protein
, ✔✔describe tyrosine kinase receptors enzyme - ✔✔ligand binds
receptors dimerize
receptors autophosphorylate
activate target protein by phosphorylation
✔✔describe G-protein coupled receptors - ✔✔ligand binds
receptor changes shape
signal transferred to G protein
G protein changes shape
GDP released so GTP can bind and activate G protein
By complex dissociates from a subunit
✔✔what are the four common G protein second messengers - ✔✔cGMP
Ca2+
IP3/DAG
cAMP
✔✔what are second messengers - ✔✔Molecules that activate additional enzymes in the
cytosol
✔✔Inositol-Phospholipid Pathway - ✔✔IP3 binds to ER ca2+ channels
Ca2+ is released into cytoplasm
IP3 phosphorylates to IP4
DAG and Ca2+ activate PKC
Ca2+ activates calmodulin
✔✔how can cAMP levels increase and decrease - ✔✔Gas activates adenylate cyclase
(AC) which converts ATP into cAMP
Gai inhibits AC
✔✔adenylate cyclase pathway - ✔✔Gas activates AC
AC catalyzes ATP--> cAMP
cAMP binds PKA
active PKA phosphorylates proteins
proteins are dephosphorylated by phosphatase
✔✔hormone clearance mechanisms - ✔✔ligand removal by distant tissues
ligand taken up by nearby cell
ligand degraded by extracellular enzymes
ligand-receptor complex removed by endocytosis
receptor inactivation
inactivation of signal transduction pathway
✔✔characteristics of neuroendocrine system - ✔✔
QUESTIONS AND ANSWERS SURE A+
✔✔what types of hormones use cytosolic receptors w/ examples. how does it work -
✔✔hydrophobic hormones
ex. thyroid hormones, steroid hormones
ligand passes through membrane
bind to receptor in cytoplasm or nucleus
ligand-receptor complex binds to DNA sequence
recruits other transcription factors to target genes
can alter production of specific mRNAs or trigger a cascade
✔✔what types of hormones use transmembrane receptors - ✔✔hydrophilic
peptide hormones
most amine hormones
✔✔describe receptor guanylate cyclase - ✔✔ligand binds
change in receptor conformation
activates guanylate cyclase
converts GTP to cGMP (second messenger)
cGMP activates PKG
PKG phosphorylates target protein
, ✔✔describe tyrosine kinase receptors enzyme - ✔✔ligand binds
receptors dimerize
receptors autophosphorylate
activate target protein by phosphorylation
✔✔describe G-protein coupled receptors - ✔✔ligand binds
receptor changes shape
signal transferred to G protein
G protein changes shape
GDP released so GTP can bind and activate G protein
By complex dissociates from a subunit
✔✔what are the four common G protein second messengers - ✔✔cGMP
Ca2+
IP3/DAG
cAMP
✔✔what are second messengers - ✔✔Molecules that activate additional enzymes in the
cytosol
✔✔Inositol-Phospholipid Pathway - ✔✔IP3 binds to ER ca2+ channels
Ca2+ is released into cytoplasm
IP3 phosphorylates to IP4
DAG and Ca2+ activate PKC
Ca2+ activates calmodulin
✔✔how can cAMP levels increase and decrease - ✔✔Gas activates adenylate cyclase
(AC) which converts ATP into cAMP
Gai inhibits AC
✔✔adenylate cyclase pathway - ✔✔Gas activates AC
AC catalyzes ATP--> cAMP
cAMP binds PKA
active PKA phosphorylates proteins
proteins are dephosphorylated by phosphatase
✔✔hormone clearance mechanisms - ✔✔ligand removal by distant tissues
ligand taken up by nearby cell
ligand degraded by extracellular enzymes
ligand-receptor complex removed by endocytosis
receptor inactivation
inactivation of signal transduction pathway
✔✔characteristics of neuroendocrine system - ✔✔
