Biol 202

Front 1

Cells interact with and receive signals from their environment

Back 1

Layer sandwich of molecules
Chemical signals received by cell surface receptors.

Front 2

Downstream siganaling pathways (2 type)

Back 2

1. short term
2. Long term

Front 3

Endorine glands secrete hormones that

Back 3

affect distant target ells

Front 4

Examples

Back 4

adrenal , thymus, etc gland

Front 5

The cellular response can be short-term or long-term

Back 5

short-term: rapidly execute, rapidly inactivating, not all or nothing !
long-term:time-frames less critical and decision is more critical

Front 6

Long term decision

Back 6

switch like and decision. Make sure you don't make the wrong decision.

Front 7

Ligands bind to receptors according to chemical equilibrium
R+ L -> RL and Kd

Back 7

The physiological response is way more sensitive than the equilibrium constant.

Front 8

Adrenaline (epinephrine) is

Back 8

a hormone that triggers short-term responses:
increase cardiac contraction
Conversion of glycogen to glucose
Inhibition of glycogen synthesis
skeletal muscle convert glycogen to glucose.

Front 9

Andrenaline was discovered twice and is used as a

Back 9

vasoconstructive medicine
( cybulski & Jokichi)
counter act anaphylaxis

Front 10

G proteins

Back 10

coupled receptor ( GPCRs) respond to many hormon signal ( c1, c2 , c3 , c4), 7 helixes.

Front 11

Transmembrane domain distort which

Back 11

lead to cytolic phase of the protein. GPCR is acient.

Front 12

G-proteins are trimeric

Back 12

GTPases that transduce hormone signals
GDP-bound "off" state

Front 13

The node /click of in of switch 1 & 2 (prong)in Gtp state

Back 13

In GDP bound state: off

Front 14

Hormone binding to the GPCR recruits

Back 14

the G-proteins

Front 15

Binding of hormone induces a conformational change in receptor

Back 15

the G-protein binds to the GPCR and becomes activated

Front 16

The active G=protein transduces the signal to an

Back 16

effector protein: hormone dissociates from receptor: Gm binds to effector, activating it
Hydrolysis of GTP to GDP causes G to dissociate from effector and reassociate with G

Front 17

Adenylyl cyclase is a common effector of

Back 17

activated G-proteins and makes cAMP
cAMP is a second messenger

Front 18

cAMP in turn activateds protein kinase A

Back 18

which has regulatory subunit and catalytic subunit.

Front 19

Protein kinases A directily contrls the

Back 19

molecules of glycogen metabolism

Front 20

Multi-step activation results in aplification: 1 epinephrine = 10 cAMP

Back 20

a more sensitive responses than anticipated

Front 21

Second messengers are ca common feature

Back 21

of signaling pathways:
example: PKA, PKG, PKC,

Front 22

IP3 and DAG are produced by stimulation of phospholipase C

Back 22

different subunits of G-proteins can do the job.
Taking a fast reaction and make it fast so the effector protein can sense signal and thus a game of ping pong between the receptor and the effector

Front 23

The ball that being sent back is the

Back 23

G-alpha or beta subunit

Front 24

SInaling is a competitive balance between stmulation and inhibition

Back 24

Different inhibitory hormone: adenylyl cyclase
Stimulator hormones : epinephrine, glucogon ACTH
Inhibitory hormon: PGE1, adenosine