Biochemical Signaling

Question 1

What do target cells have to respond to the hormone?

Answer 1

a specific receptor for the hormone.

Question 2

What kind of hormones are pancreatic islet hormones?

Answer 2

peptide hormones

Question 3

What do pancreatic islet hormones do?

Answer 3

peptides that regulate glucose metabolism: insulin.

Question 4

What do catecholamines control?

Answer 4

controls glucose and lipid metabolisms.

Question 5

What hormone controls lipid metabolism and controls glucose?

Answer 5

catecholamines

Question 6

What are catecholamines?

Answer 6

Derivatives of tyrosine.

Question 7

What are catecholamines targets?

Answer 7

alpha and beta adrenergic receptors.

Question 8

What hormone regulates muscle function?

Answer 8

catecholamines.

Question 9

What are steroid hormones?

Answer 9

derivatives of cholesterol.

Question 10

What do steroid hormones include?

Answer 10

glucocorticoids, mineralocorticoids, and sex hormones.

Question 11

Which major class of hormones slip right through the membrane and don’t need help?

Answer 11

steroid hormones

Question 12

What are growth hormones?

Answer 12

peptide hormones targeting receptors on the bone, muscle, and connective tissue.

Question 13

Growth hormones are what kind of hormones?

Answer 13

peptides

Question 14

What hormones control the rate of growth?

Answer 14

growth hormone.

Question 15

What are the two hormonally active catecholamines that adrenal medulla synthesizes?

Answer 15

Norepinephrine (Noradrenalin) and Epinephrine (Adrenalin)

Question 16

What do adrenergic receptors contain?

Answer 16

Agonist and Antagonist?

Question 17

An agonist replicates what?

Answer 17

the effect of a hormone.

Question 18

What effect will an antagonist replicate?

Answer 18

bind on to the hormone and compete for the substrate.

Question 19

What occurs to the growth hormone receptor upon hormone binding?

Answer 19

dimerizes

Question 20

What does hormone binding induce?

Answer 20

receptor dimerization that is necessary for signal transduction.

Question 21

Describe the structure of the growth hormone?

Answer 21

a 4 helix bundle. 191 amine acids comprises it

Question 22

How does the hormone receptor get the signal across?

Answer 22

has to get transduce through the membrane inside the cell.

Question 23

What occurs in the autophosphorylation activates insulin receptor?

Answer 23

dimerization may or may not require ligand bonding and one subunit phosphorylates the other.

Question 24

What occurs to the loops in the Tyrosine Kinase Domain of Insulin Receptor?

Answer 24

Tyrosines flanking the active site and they must phosphorylate to remove inhibitory loop.

Question 25

What occurs once tyrosines phosphorylate to remove inhibitory loop?

Answer 25

the loop opens up, is free to phosphorylate other substrates.

Question 26

What are autoinhibited?

Answer 26

Unphosphorylated kinases

Question 27

What moves out the way upon phosphorylation?

Answer 27

activation loop.

Question 28

What is SH2 (Sark)?

Answer 28

a kinase involved in a signal transduction.

Question 29

SH2 binds to what?

Answer 29

Phospho-Tyr Residues

Question 30

What kind of mechanisms occur between P-Tyr and other proteins?

Answer 30

Docking mechanism

Question 31

What does SH3 do? (Sark Homology 3)?

Answer 31

Binds polyprotein sequences and other proteins. These signaling cascades get turned on this manner.

Question 32

Where is the signal amplified in the Ras Signaling Cascade?

Answer 32

amplified through this cascade of phosphorylation.

Question 33

What is the end results in RAS signaling Cascade?

Answer 33

phosphorylation and activation of transcription factors that turn on genes to alter the phenotype of the cell.

Question 34

How do you prevent promiscuous cross talk?

Answer 34

Location, Localize kinases to sites in the cell where their function is needed.

Question 35

What are crosstalks?

Answer 35

Intermingling pathways of signal transduction between pathways.

Question 36

What does the Src Structure reveal?

Answer 36

mechanism for autoinhibition.

Question 37

What relaxes the structure of the Kinase domain to open its substrate binding pocket?

Answer 37

binding of SH2 or SH3 domains to their ligands in another proteins or the dephosphorylation of Tyr527.

Question 38

What allows phosphorylation of Tyr 416?

Answer 38

The relaxation of the kinase domain to open its substrate binding pocket.

Question 39

What doe Tyr-PO4 of Tyr 416 form?

Answer 39

A salt bridge to Arg409.

Question 40

Why does a salt bridge form to Arg409?

Answer 40

to relax the activation loop to its unblocked conformation.

Question 41

What allows Glu 310 to form catalytically important salt bridge with Lys295?

Answer 41

The Arg409 relaxation of the activation loop to its unblocked conformation

Question 42

What is step 1 in the Src Activation?

Answer 42

Binding to phosphoprotein partner or dephosphorylation of Tyr527.

Question 43

Binding to the phosphorylation partner or dephosphorylation of Tyr527 does what?

Answer 43

opens the substrate binding cleft of Src.

Question 44

What is step 2 in the Src Activation?

Answer 44

Tyr 416 is phosphorylated to free activation loop of the active site of the enzyme.

Question 45

What do protein kinases often have?

Answer 45

inhibitory domains (loops) that occupy the active site when not phophorylated.

Question 46

In the activation of protein kinases the phosphorylation of the loop results in what?

Answer 46

in its conformation out of the active site of the enzyme allowing substrate access.

Question 47

What enzymes are equally important as kinases?

Answer 47

protein tyrosine phosphatases

Question 48

What isn't possible without reversal of modifications?

Answer 48

regulation

Question 49

Dephosphorylation of Src where is important for what?

Answer 49

At Tyr527 for its activation.

Question 50

Active site residue form what?

Answer 50

covalent bond to phosphate hydrolyzed.

Question 51

Ser/Thr phosphotases are similar except that?

Answer 51

their substrate binding pockets are more shallow due to reduced size of the substrate.

Question 52

What is important to know about the domains N-SH2 and C-SH2 in protein tyrosine phosphatase SHP-2?

Answer 52

These domains are autoinhibitory until bound to a substrate.

Question 53

What occurs when the domain N-SH2 and C-SH2 move?

Answer 53

the inhibitory D'E loop moves out of the active site.

Question 54

What comprises 1% of the total cellular proteins?

Answer 54

Protein phosphatase PP2A.

Question 55

What are hormones?

Answer 55

Molecules secreted by specialized glands of vertebrates and plants designed to signal specific target tissues of the body.