Biochem

Question 1

epinephrine (adrenaline)

Answer 1

receptor = GPCR(g-protein coupled receptor)

Question 2

cortisol hormone

Answer 2

intracellular receptor

Question 3

estradiol hormone

Answer 3

intracellular receptor

Question 4

glucagon hormone

Answer 4

GPCR

Question 5

growth hormone

Answer 5

tyrosine kinase-associated receptor

Question 6

Insulin (hormone)

Answer 6

Receptor Tyrosine Kinase

Question 7

Testosterone

Answer 7

Intracellular receptor

Question 8

Epidermal Growth Factor (EGF)

Answer 8

Receptor tyrosine kinase (RTK)

Question 9

platelet-derived growth factor (PDGF)

Answer 9

receptor tyrosine kinase (RTK)

Question 10

Nerve growth factor (NGF)

Answer 10

Receptor tyrosine kinase (RTK)

Question 11

Transforming growth factor-B

Answer 11

Serine/threonine receptor kinase

Question 12

Nitric oxide (NO)

Answer 12

permanently binds guanylyl cyclase

Question 13

Acetylcholine (ACh)

Answer 13

GPCR

Question 14

Hormones that act on GPCRs

Answer 14

Epinephrine, glucagon, Acetylcholine

Question 15

Hormones that bind to intracellular receptors

Answer 15

• cortisol, estradiol, testosterone, Thyroid hormone (T3/Thyroxine), Vitamin D3

Question 16

hormones that bind to RTKs (receptor tyrosine kinases)

Answer 16

• insulin, EGF (epidermal growth factor), PDGF (platelet-derived GF), NGF (nerve GF)

Question 17

s and i GPCR signaling

Answer 17

Effector: adenylyl cyclase
2nd mess: cAMP (S - up, I- down)
Receptors: S - beta Adrenergic, glucagon, serotonin, vasopressin RsI - alpha adrenergic, Ach Rs

Question 18

q GPCR signaling

Answer 18

effector: PLC
2nd mess: IP3, DAG
Receptor: Ach (o)

Question 19

t GPCR signaling

Answer 19

effector: cGMP phosphodiesterase
2nd mess: cGMP (down)
Receptor: rhodopsin

Question 20

NO synthesis

Answer 20

substrate: argenine
product: citrulline and NO
3 NO synthases:
- Neuronal Constitutive NOS (nNOS)
- Endothelial constitutive NOS (eNOS): in smooth mm.
- Induced NOS (iNOS): in macrophages

Question 21

Phospholipase C cascade

Answer 21

initiated by RTK, 
activates Phosphoinositide (PI) pathway (w/ GPCRs)
--> increase cytosolic Ca2+ levels 
(boost signaling w/ Ca2+)
** directly makes DAG and Ins-1,4,5-P3

Question 22

Receptor Tyrosine Kinase (RTK) mech

Answer 22

set of 2 Rs on 2 intracellular proteins w/ tyrosine kinases.
Activate when ligands bind –> auto-phosphorylate and dimerize.
ligands: EGF, FGF, insulin (growth factors!)
pathways activated: Src, Phospholipase C, MAP kinase, PI-3K

Question 23

Insulin Receptor Substrate (“IRS”)

Answer 23

Insulin-specific receptor that binds to RTK (when RTK = activated),
=> docking station for mTOR, AkT, and MAPK

Question 24

AC (adenylyl cyclase) pathway

Answer 24

AC –(activate)–> cAMP,

2 cAMP –(activate)–> PKA –> (phosphorylate target proteins or cAMP Response Element ““CREBP””)

Question 25

protein kinase C

Answer 25

family of ser/thr kinases,
used in signaling cascades to phosphorylate target molecs.
(activated by DAG&Ca2+ from GPCRS, cGMP from NPRs)
promote cell proliferation

Question 26

Major cell cycle checkpoints

(4)

Answer 26

1. restriction point (end of G1): to divide or not to divide?
2. S phase checkpoint: is DNA is damaged, and not fixable?
3. G2/M checkpoint: is replication completed?
4. Spindle assembly checkpoint (M): are chromatids properly arranged on spindles?

Question 27

Clinical disease assoc. w/ problems with heme synth pathway…

• ALA synthase
• a-ALA dehydratase
• uroporphyrinogen I synthase
• uropophyrinogen decarboxylase

Answer 27

1. ALA synthase (EtOH, barbituates, hypoxemia) => anemia
2. ALA dehydratase (Lead toxicity) => Bx changes…
3. Uroporphyrinogen I synthase (Acute intermittent pophyria) => urine darkens on standing
4. Uroporphyrinogen decarboxylase (Porphyria cutanea tarda) => photosensitivity