mechanisms of hormone action

Question 1

what is neuroendocrine signaling

Answer 1

nerve cell to blood vessel going to a target cell

halfway between endocrine and neurotransmitters

Question 2

adrenaline effect on alpha receptors

Answer 2

vessel constricts

Question 3

adrenaline effect on beta receptors

Answer 3

vessel dilates

Question 4

define an endocrine gland

Answer 4

ductless system

secretes hormone into blood stream

Question 5

describe the synthesis of chonesterol hormones

Answer 5

cholesterol taken up by the cell
stored in cell in esterified form
transported into mitochondria
cytochome P45 cleaves enzyme removing side chain
its now pregnenolone
this is metabolised to form further cholesterol hormones

Question 6

describe the synthesis of peptide hormones

Answer 6

translated in the RER
pre-pro hormone
sent to golgi
further processed to make active form

Question 7

what kind of post-translational modifications occur to peptide hormones

Answer 7

glycosylation
disulphide bond formation
subunit assembely
endopeptidase cleavage
dimerisation

Question 8

how are steriod hormones transported

Answer 8

with a carrier binding protein

eg albumin

Question 9

where do water soluble hormones have their receptor

Answer 9

on cell surface

extracelular

Question 10

where do water insoluble hormone have their receptor

Answer 10

intracellular

diffuse through the membrane

Question 11

define hormone

Answer 11

chemical messenger secreted by specific cells and tissues that travel ( often in the blood) to act on specific high affinity receptors on a target cell

Question 12

define a ligand

Answer 12

a molecule that binds to a specific site on a protein or other molecule
eg a hormone binding to a receptor

Question 13

main property of a steriod hormone

Answer 13

hydrophobic

Question 14

main properly of a peptide hormone

Answer 14

hydrophillic

Question 15

main properties of hydrophobic hormone

Answer 15

water hater 
insoluble in water
needa  carrier molecule/protein
intracellular receptor
synthesis on demand
resistant, longer half life

Question 16

main properties on hydrophillic hormones

Answer 16

water loving
soluble in water and blood
degraded quickly so short half life
extracellular receptor

Question 17

give two examples of amino acid hormones

Answer 17

thryioxine and adrenaline

Question 18

properties of thyrioxine

Answer 18

hydrophobic
stored in thyriod
small and potent
intracellualr receptor
long half life in circulation

Question 19

properties of adrenaline

Answer 19

hydrophillic
blood soluble
easily degraded in circulation
extracellular receptor

Question 20

hormones that use intracellular receptors

Answer 20

cortisol
estradiol
testosterone
progesterone
thyroxine

Question 21

explain briefly GPCRs

Answer 21

G protein coupled receptors
singla binds to extracellular receptor, GPCR changes conformation
GDP is swapped for GTP
subunits of GPCR now active
this can now regulate downstream effets using 2nd messegers

Question 22

examples of hormones using enzyme couples receptors

Answer 22

insulin
growth hormone
epidemal growth factor

Question 23

briefly describe enzyme couples receptors

Answer 23

singple cytoplasmic domain with enzymatic activity in cytoplasm
hormone binds causing dimerisation activating enzyme
catalytic activity inside cytosol such as kinase

Question 24

give an enzyme of an enzyme coupled receptor

Answer 24

receptor tyrosin kinases

Question 25

kinase

Answer 25

enzyme to add phosphates

Question 26

phosphatases

Answer 26

enzyme to remove the phosphates

Question 27

describe the molecular swtich by phosphoylation model

Answer 27

protein kinase uses ATP to add a phosphate to the molecule turning it on protein phosphate can then remove the phosphate turning the signal back off

Question 28

example of a second messenger

Answer 28

cAMP DAG IP3 Ca2+

Question 29

decribe the process of adrenaline from binding to its receptor to its celular effects

Answer 29

binds to GPCR conformational change, GDP to GTP now active activated adenylyl cyclase which uses ATP to make cAMP this activated protein kinase A leds to inibition of glycogen synthsis and promites glyogen breakdown

Question 30

how are ligands regulated?

Answer 30

the secretion | the proccessing eg prohomones need to be conveterted to active before being used as a ligand

Question 31

how are receptors regulated?

Answer 31

isoforms expression pattern receptor number receptor affinity

Question 32

where are beta adrenergic receptors found?

Answer 32

adrenaline receptors | surface of skeletal muscle

Question 33

where are alpha adrenergic receptors found

Answer 33

gut lining

Question 34

how is receptor number regulated

Answer 34

eg the insluin receptor receptors on cell surface are cycled internally changing the number encodytosed internally, some destroyed or stored in a vesile before being cycled back up again

Question 35

name normones with an intracellular receptor

Answer 35

cortisol testosterone progesterone

Question 36

name hormones with an extracellular receptor

Answer 36

adrenaline glucagon oxytocin ADH

Question 37

why are some hormones more potent that others?

Answer 37

some can cause more amplification than others

Question 38

what shoukd you include to begin of an essay

Answer 38

define hormone define cell communication define hormone signalling