0521 Flashcards
(34 cards)
how does acetyl CoA act as an allosteric activator of gluconeogenesis?
increases activity of pyruvate carboxylase (pyruvate to oxaloacetate)
homocysteine is elevated in?
both folic acid and B12 defs.
whereas only methylmalonyl CoA is elevated in B12 def.
how does TNF-a induce insulin resistance?
activate serine kinases to phosphorylate insulin receptor substrate-1 serine residues (thus preventing normal tyrosine phosphorylation by insulin)
insulin tyrosine kinase activity
causes phosphorylation of “insulin receptor substrates” that then activate PROTEIN PHOSPHATASE, which dephosphorylates (activates) glycogen synthase to promote glycogen synth.
heme inhibits what step of its synthesis?
ALA synthase, which forms aminolevulinic acid from glycine and succinyl CoA.
*glucose also inhibits this step
what step of TCA cycle generates GTP?
succinyl CoA synthetase (succinyl CoA to succinate)
what step in gluconeogenesis requires GTP?
PEPCK (oxaloacetate to PEP)
repressor protein of Lac operon binds where?
to operator.
*allolactose prevents repressor protein from binding here
how does glucose inhibit activator of Lac operon?
decrease adenylyl cyclase
= decrease cAMP
= decrease catabolite activator protein (CAP) that normally positively regulates operon
why is proline important in collagen formation?
ring structure introduces bends in alpha helix
cause of wrinkles with aging
decreased synth and net loss of dermal collagen and elastin
why is ketogenic diet recommended in pyruvate dehydrogenase deficiency?
carbohydrates may aggravate lactic acidosis (pyruvate already being shunted to lactate since it can’t be converted to acetyl CoA).
ketogenic AAs: lysine, leucine.
full mutation of FMR1 gene
> 200 CGG repeats causing hypermethylation leading to gene inactivation.
manifests as Fragile X syndrome.
vs. premutation (< 200 repeats).
what bases are hypermethylated in fragile X syndrome?
cytosine
androgenetic alopecia
most common cause of hair loss in both males and females.
aka male pattern baldness.
POLYGENIC inheritance w/variable penetrance.
pathogenesis of polycythemia in COPD
COPD can cause hypoxia sufficient enough to stimulate EPO production by renal cortical cells
rubella (German measles)
febrile maculopapular rash starting on face, spread to trunk and extremities (also seen in rubeola).
rubella rash spread faster.
does not darken or coalesce.
PLUS postauricular, occipital lymphadenopathy
rubella is part of what virus family?
toga virus
how does a naked RNA molecule induce viral protein synth in host cell?
directly acts as mRNA using host’s intracellular machinery for translation-
only works for naked viruses with ss (+) RNA
TX of CF malabsorption
secondary to panc insuff-
treat with panc enz supp
where are receptors for thyroid hormones?
nucleus
initial skin lesion of Lyme disease?
erythema migrans- at the site of tick bite. begins as erythematous macule. enlarges with red border as bacteria migrate slowly through skin. may see central clearing within patch.
what causes green discoloration of pus or sputum during bact infx?
release of myeloperoxidase (MPO) from neutrophil azurophilic granules.
MPO is a blue green heme-containing pigmented molecule
sunlight catalyzes what step in vit D synth?
7-dehydrocholesterol to cholecalciferol (D3)
