Biochem: nutrition and metabolism Flashcards
vitamins that can have excess/toxicity
water: B3, C; fat: A, D
bitot spots are caused by vitamin deficiency/excess
A deficiency
pseudotumor cerebri in this vitamin def/xs
A excess
hepatic toxicity in this vitamin def/xs
A excess
beriberi in this vitamin def/xs
B1 deficiency
manifestations of beriberi
dry: polyneuritis, symmetrical muscle wasting
wet: high output cardiac failure (DCM), edema
how to dx B1 deficiency
increased transketolase activity after b1 administration
cheilosis in this vitamin def/xs
B2 (riboflavin) deficiency
this vitamin def mimics tryptophan def
B3/niacin
glossitis and pellagra in this vit def/xs
B3/niacin deficiency
Hartnup disease can cause this vitamin def/xs
B3/niacin deficiency
facial flushing (PG), hyperglycemia, and hyperuricemia in this vitamin def/xs
B3/niacin excess. note: given to lower cholesterol
this vitamin is important for co-enzyme A function
B5/pantothenic acid
INH and OCPs induce this vitamin def/xs
B6/pyridoxine deficiency
neurologic complications and sideroblastic anemia in this vitamin def/xs
B6/pyridoxine deficiency
this vitamin is important for carboxylation enzymes
B7/biotin
def/xs caused by antibiotics or excessive ingestion of raw egg whites
biotin deficiency (rare). similar sx to B5 def
def/xs caused by drugs such as phenytoin, sulfonamides, and methotrexate
B9/folate deficiency
calcium oxalate nephrolithiasis in this vitamin def/xs
C excess
increased risk of iron toxicity (in predisposed individuals) in this vitamin def/xs
C excess
def/xs can be seen in granulomatous diseases
D excess
hemolytic anemia, acanthocytosis, and neuro problems in this vitamin def/xs
E (tocopherol/tocotrienol) deficiency. neuro sx similar to B12 deficiency, but without megaloblastic anemia, hypersegmented neutrophils or elevated methylmalonic acid
neonates are injected at birth with this vitamin
K. to prevent hemorrhagic disease
deficiency in this can cause decreased adult hair
zinc deficiency. also delayed woudn healing, hypogonadism, acrodermatitis enteropathica. and may predispose to alcoholic cirrhosis
fomepizole MOA
inhibits alcohol dehydrogenase. antidote for methanol or ethylene glycol
disulfiram inhibits
acetylaldehyde dehydrogenase
RDS glycolysis
phosphofructokinase-1 (converts F6P to F16BP)
RDS gluconeogenesis
fructose-1,6-bisphosphatase
RDS TCA cycle
isocitrate dehydrogenase
RDS glycogenesis
glycogen synthase
RDS glycogenolysis
glycogen phosphorylase
RDS HMP shunt
G6PD
RDS de novo pyrimidine synthesis
carbamoyl phosphate synthetase II (first step, converts glutamine + CO2 to CP)
RDS de novo purine synthesis
PRPP
RDS urea cycle
carbamoyl phosphate synthetase I
RDS fatty acid synth
acetyl-CoA carboxylase (turns acetyl-CoA into malonyl-CoA)
RDS fatty acid oxidation
carnitine acyltransferase I (helps shuttle into/across mitocondrial membrane)
RDS ketogenesis
HMG-CoA synthase (converts acetyl-CoA into HMG-CoA)
RDS cholesterol synthesis
HMG-CoA reductase (converts HMG-CoA to mevalonate)
Hexokinase vs. glucokinase: tissue
glucokinase in liver and beta cells
Hexokinase vs. glucokinase: Km and Vmax
glucokinase has a high Km and high Vmax
Hexokinase vs. glucokinase: feedback inhibition
hexokinase is inhibited by G6P
Hexokinase vs. glucokinase: induced by insuline and associated with MODY
glucokinase
FBPase-2 promotes
gluconeogenesis. Turns F26BP (not part of main pathway) into F6P
PFK-2 promotes
glycolysis. Turns F6P into F26BP (not part of main pathway), which catalyzes conversion of F6P into F16BP (on the way to glycolysis)
F26BP promotes
conversion of F6P into F16BP (on the way to glycolysis)
glucagon effect on cAMP
increases
insulin effect on cAMP
decreases
cofactors required for pyruvate dehydrogenase
B1, B2, B3, B5, lipoic acid
name intermediates, in order, of TCA
citrate, isocitrate, aKG, succinyl-CoA, succinate, fumarate, malate, OAA
CO2 is generated after these steps of TCA
after iso citrate and after aKG
ETC inhibitor(s)
rotenone (I), antimycin (III), CO/CN (IV)
ATP synthase inhibitor(s)
oligomycin
ETC-ATP uncoupling agent(s)
2,4-dinitrophenol, aspirin, thermogenin
which chains (even or odd) can lead to gluconeogenesis
odd chains
def. in fructose intolerance
aldolase B (converts F1P into DHAP and glyceraldehyde)
def. in classic galactosemia
galactose-1-phosphate uridyl transferase