Flashcards in Biochemistry Deck (255)
Only vitamins with excess problems.
Vit A, Vit B3, Vit C, Vit D
Dermatitis, enteritis, alopecia, adrenal insufficiency
B6 f(x) and name?
Pyridoxine. Pyridoxal phosphate used for transamination, decarbox, glycogen phosphorylase. Neurotransmitter synthesis.
Peripheral neuropathy, sideroblastic anemia. Cheilosis, glossitis, dermatitis. INH --> B6 deficiency symptoms b/c chemically similar to pyridoxine and competes in synthesis of neurotransmitters while also increasing urinary excretion.
B7 f(x) and name?
Biotin. Cofactor for 1C adding rxns (acetyl-Coa carboxylase, pyruvate carboxylase, propionyl carboxylase)
Abx or excessive ingestion of egg whites. Dermatitis, alopecia, enteritis.
B9 f(x) and name?
Folic acid. Converted to THF for base synthesis. Absorbed in jejunum. Leafy green veggies. Small pool in liver.
Macrocytic, megaloblastic anemia. Inhibits dTMP synthesis. Glossitis, no NEURO. Dx - inc. homocysteine and normal methylmalonic acid. Tx w/ folate and thymidine.
B12 f(x) and name?
Cobalamin. Homocysteine methyltransferase (methionine pathway) and methylmalonyl-CoA mutase co-factor. Large reserve in liver.
Macrocytic, megaloblastic anemia. Parasthesias, subacute combined degen due to abnl myelin. UMN signs (lateral corticospinal dmg). Inc homocysteine AND methylmalonic acid. Buildup of methylmalonic acid -> myelin synthesis abnormalities. Etios - vegan, malasorption, lank of intrinsic factor, absence of terminal ileum
Vit C f(x) and name?
Ascorbic acid. Antioxidant, iron absorption, hydroxylation of collagen residues, dopamine -> NE.
Excess Vit C?
N/v, d, fatigue, calcium oxalate nephrolithiasis.
Deficient Vit C?
Scurvy - collagen syntehsis defect. Swollen gums, brusing, anemia, poor wound healing, corkscrew hair
Vit D f(x) and name?
D2 - (ergocalciferol from plants). D3 (cholecalciferon from milk). 1,25 = active form. Intestinal absorption of Ca+ AND phosphate. Inc. bone mineralization.
Deficient Vit D?
Rickets - bone pains and deformity. Osteomalacia (bone pain and weakness in adults).
Excess Vit D?
Hypercalcemia, hypercalciuria, loss of appetite, stupor. Scene in sarcoidosis.
Vit E f(x) and name?
Tocopherol/tocotrienol. Antioxidant for ERYTHROCYTES and membranes.
Deficient Vit E?
Hemolytic anemia, acanthocytosis (spiked RBCs), muscle weakness, posterior column and spinocerebellar tract demyelination. (Similar to B12 def except NO megaloblastic anemia and hypersegmented neutrophils)
Vit K f(x) and name?
Cofactor for carboxylation for Glu for Klotting. (1972, Canada-Sweden).
Deficient Vit K?
Neonatal bleeding (inc. PT and aPTT). Injection (guts can't absorb b/c sterile intestine).
Delayed wound healing, hypogonadism, dec. adult hair, dysgeusia (Taste distortion)
Alcohol dehydrogenase (cytosol); Acetalaldehyde dehydrogenase (mitochondria) producing acetate.
Limiting reagent is NAD+. Zero-order. Increases NADH/NAD+ ratio in liver ---> lactic acidosis, fasting hypoglycemia, hepatosteatosis)
What drugs affect ethanol metabolism pathway?
Disulfiram -| acetylaldehyde dehydrogenase.
Fomepizole inhibits alcohol dehydrogenase. Antidote for methanol or ethylene glycol poisoning.
Protein deficient MEAL -> Malnutrition, Edema, Anemia, Liver (large b/c of fatty change 2/2 dec. apolipoprotein to move out VLDL). Also ascites.
Total calorie malnutritions -> MUSCLE wasting.
What metabolic pathways occur in the mitochondria?
FA oxidation, acetyl-CoA production, TCA, oxidative phosphorylation; Parts of heme synthesis, urea cycle, and gluconeogenesis.
What metabolic pathways occur in cytoplasm?
Glycolysis, FA synthesis, HMP shunt, protein, steroid, cholesterol synthesis. Parts of heme, urea cycle, gluconeogenesis.
Net ATP production w/ glucose?
32 w/ malate-asp shuttle (heart and liver). 30 net w/ gylcerol-3-phosphate shuttle (muscle). 2 net if anaerobic.
Enzyme responsible for first step of glycolysis?
Hexokinase (most tissues) - high affinity, basal, feedback inhibited by glucose-6-P.
Glucokinase (liver, beta cells) - faster response, insulin induced, inhibited by fructose-6-P, implicated in MODY