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Flashcards in Biochem metabolism Deck (129)
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During pyruvate metabolism, What processes occur in the cytosol? Mitochondria?

Alanine & lactate are produced in cytosol;
Oxaloacetate & Acetyl-CoA are produced in the mitochondria


Where does the TCA cycle reactions occur?



ETC & oxidative phosphorylation has a main function of what?

put H+ into inter membrane space to use as a gradient to power ATPase


What drug(s) inhibits complex 1 of ETC?

rotenone, barbituates, amytal, MPTP (synthetic demorol) => parkinson cause


What drug(s) inhibits complex 3 of ETC?

Antimycin A


What drug(s) inhibits complex 4 of ETC?

Cyanide, CO, NH3-, H2S


What drug(s) inhibits complex 5 of ETC?



What drug(s) inhibits CoQ of ETC



Name ETC inhibitors along w/ action

rotenone, CN, antimycin A, CO => Directly inh electron transport leading to decreased proton gradient & ATP synthesis block


Name ATP synthase (complex 5) inhibitors along w/ action

Oligomycin=> directly inhibits mitochondrial ATPsynthase leading to increased proton gradient => NO ATP PRODUCED bc electron transport stops


Describe how uncoupling agents affect the ETC

increase permeability of inner Mt membrane leading to decreased proton gradient & increased O2 consumption => ATP synthesis stops but electron transport continues so HEAT IS PRODUCED


What are uncoupling agents of ETC?

2,4 DNP (wood preserver);
Aspirin (overdose fever);
thermogenin (brown adipose - baby fat)


What are the irreversible enzymes of gluconeogenesis? name location & substrate/product

pyruvate CB in Mt (biotin, ATP, acetyl-CoA)= pyruvate to OAA;

PEP CB in cytosol (GTP) = oxaloacetate to phosphoenolpyruvate;

F-1,6-BPase in cytosol = F-1,6-BP to Fructose-6-P;

G-6-Pase in ER = Glucose-6-P to glucose


Where does gluconeogenesis occur primarily? where can it not occur?

occurs in liver

cannot in muscle bc it has no G-6-Pase


What type of FA chains can serve as glucose sources? Why?

Odd bc yields 1 propionyl-CoA during metabolism to enter TCA (succinyl-CoA) to undergo gluconeogenesis

Even only yield acetyl-CoA so cannot make new glucose


What is the purpose of the HMP shunt?

provide NADPH from G-6-P for reductive rxn then produces ribose for nucleotide syn & glycolytic intermediates


Where do the 2 phases of HMP shunt occur? what is the difference in them?

Oxidative is irreversible using G-6-P DH (rate limiter) & NADP+to produce CO2, NADPH, Ribulose-5-P for PRPP generation for nucleotide syn

Nonoxidative is reversible & requires Thiamine & transkelotases to produce ribose-5-P, G3P, F6P


What cells can use respiratory burst (oxidative burst)? What is involved?

Neutrophils & monocytes activate membrane bound NADPH oxidase for immune response & release of ROI


What are the basic roles of NADPH?

create AND neutralize ROIs


Where in the neutrophil or monocyte does respiratory burst occur?



What is the result if NADPH oxidase is deficient?

chronic granulomatous disease


How does a WBC of pt w/ chronic granulomatous disease make ROI?

utilize H2O2 that is generated by invading organism (bacterial catalase) & convert it to ROI


If a patient is deficient in G6PD or NADPH oxidase, what type of infection risk is present?

catalase positive (S. aureus, Aspergillus) bc they neutralize own H2O2 leaving WBCs w/o ROI to fight infection


What is the MC human enzyme deficiency? How is it inherited & who shows the most prevalence?

XLR of G6PD deficiency that is MC in blacks assoc w/ increased malarial resistance


What is the result of G6PD deficiency in RBCs?

NADPH is decreased so cannot keep glutathione reduced therefore free rad & peroxides occur leading to damage & hemolytic anemia


What will be seen on a blood smear in a pt w/ G6PD deficiency?

Heinz bodies => oxidized Hgb precipitated w/in RBCs
Bite cells result from splenic macs taking out heinz bodies thus leading to hemolytic anemia


What can induce a person w/ G6PD deficiency leading to hemolytic anemia?

fava beans (mediteranean food); sulfonamides, Primaquine, anti-TB; infection


Essential fructosuria has a defect in what and how is it inherited? What will diagnose & what Sx?

AR benign defect in fructokinase will lead to fructose in blood & urine
rare osmotic diarrhea


Fructose intolerance has a defect in what and how is it inherited?

AR deficiency in aldolase B leading to accumulation of F1P which binds phosphate resulting in inhibition of glycogenolysis & gluconeogenesis


Sx & Tx for fructose intolerance?

Sx are hypoglycemia, jaundice, cirrhosis, vomit;
Tx is to decrease intake of both fructose & sucrose (glucose+fructose)