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33 Cards in this Set
- Front
- Back
What is the rate-determining enzyme in Glycolysis?
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Phosphofructokinase-1 (PFK-1)
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What is the rate-determining enzyme in Gluconeogenesis?
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Fructose-1,6-bisphosphatase
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What is the rate-determining enzyme in TCA cycle?
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Isocitrate dehydrogenase
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What is the rate-determining enzyme in Glycogen synthesis?
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Glycogen synthase
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What is the rate-determining enzyme in HMP shunt?
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Glucose-6-phosphate degydrogenase (G6PD)
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What is the rate-determining enzyme in Glyccogenolysis?
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Glycogen phosphorylase
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In von Gierke's Disease, you are deficient in which enzyme? Which pathway does this effect?
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Glucose-6-Phosphatase.
Effects Gluconeogenesis. |
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What do you find in Von Gierke's Disease?
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Severe fasting hypoglycemia
Increased glycogen in the liver Hepatomegaly Increased blood lactate (due to muscle anaerobic metabolism) |
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What are the glycogen storage diseases?
What enzyme is deficient? |
"Very Poor Carbohydrate Metabolism"
V: Von Gierke's disease (Glucose-6-phosphatase, the last enzyme/step req in gluconeogenesis). P: Pompe's Disease (lysosomal alpha-1,4-glucosdase) C: Cori's Disease (debranching enzyme, aka alpha-1,6-glucosidase) M: McArdle's Disease (Glycogen phosphorylase in the skeletal mm) |
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What are the finding's in Pompe's Disease?
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Cardiomegaly and system findings leading to early death by age 3.
"Pompe's trashes the Pump (heart, liver, and muscle) |
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Cori's disease is a milder form of which of the other glycogen storage diseases?
What is normal in Cori's that is increased in the worse form? |
Von Gierke's (type I)
Normal lactate levles |
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What are the findings in McArdle's Disease?
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There is an increase in glycogen in the muscles, but since this disease lacks glycogen phosphorylase, glycogen can't be broken down--> painful muscle cramps, myoglobinuria w/strenous exercise.
Think M= McArdle=Muscle |
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What are the cofactors required for the Pyruvate Dehydrogenase Complex?
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"TLC For No one"
Thiamine (B1;TPP; pyrophosphate) Lipoic Acid CoA (B5) FAD (B2, riboflavin) NAD (B5, pantothenate) |
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A deficiency in Pyruvate Dehydrogenase would result in what?
Tx? |
Substrate backup, such as pyruvate and alanine, and lactate (-->lactic acidosis).
Can be congenital or acquired i.e. B1 deficiency seen in alcoholics. Findings: Neurologic defects Tx: increase intake of ketogenic nutrients (fatty food or those w/lysine, leucine) |
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Amytal, Rotenone, and MPP will inhibit which complex of the electron transport chain?
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Complex I
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Antimycin A will inhibit which complex of the electron transport chain?
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Complex III
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What compounds or molecules will inhibit Complex IV of the electron transport chain?
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Hydrogen Sulfide (H2S), Carbon Monoxide (CO), Cyanide (CN-), and Azide (N3-)
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What is the purpose of the HMP shunt (pentose phosphate pathway)?
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To provide a source of NADPH from abundantly available glucose-6-phosphate.
Note: also yields Ribose for nucleotide synthesis, and glycolytic intermediates |
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What is NADPH for?
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For reductive reactions, such as the glutathione reduction inside RBCs that protects from oxidative insult/attack (so glutathione= antioxidant).
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What is the rate-limiting step in the Oxidative phase of the HMP shunt?
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Glucose-6-P Dehydrogenase conversion of Glucose-6-P.
*note: oxidative phase is irreversible |
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What are the products in the HMP shunt?
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CO2, Ribulose-5-P, 2NADPH
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What is/are the enzymes used in the Nonoxidative (reversible) phase of the HMP shunt?
What are the end products? |
Transketolases (start with Ribulose-5-P) which require B1 (thiamine).
Ribose-5-P, G3P, F6P |
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What drugs do you not want to give to patients with a G6PD deficiency?
Why? |
Sulfonamides, Primaquine, anti-TB drugs, fava beans.
These drugs produce oxidizing agents, which will cause hemolytic anemia in a patient w/o G6PD (see FAp.102) |
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What is the most common enzyme deficiency?
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Glucose-6-phosphate Dehydrogenase (G6PD) Deficiency, X-linked.
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What are Heinz bodies?
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Oxidized Hemoglobin precipitated within RBCs, which occurs in G6PD deficiency.
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Fructose intolerance is due to hereditary deficiency of what enzyme?
What results? S/S? |
Aldolase B deficiency.
Fructose-1-P accumulation--> decreases available phosphate--> can't undergo glycogenolysis and gluconeogensis. S/S: hypoglycemia, jaundice, cirrhosis, vomiting. |
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How do you treat Fructose intolerance?
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Decrease fructose and sucrose (which has fructose).
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What enzyme is absent in classic galactosemia?
Result? |
Galactose-1-phosphate uridyltransderase (GALT)
Accumulates toxic substances like galactitol, which accumulates in the lens of the eye |
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What are the Sx of classic galactosemia?
Tx? |
FTT, Jaundice, hepatomegaly, infantile cataracts, mental retardation
tx: exclude galactose and lactose (Galactose + glucose) |
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What is the drug of choice for inhibiting alcohol dehydrogenase and tx methanol or ethylene glycol poisoning?
What drug inhibits acetaldehyde dehydrogenase? |
Fomepizole.
Disulfiram (antabuse): accumulates acetaldehyde, contributing or promoting hangover sx. |
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What enzyme converts Ethanol to Acetaldehyde? Acetaldehyde to Acetate?
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Ethanol to acetaldehyde: Alcohol dehydrogenase
Acetaldehyde to Acetate: Acetaldehyde dehydrogenase (ASIANS have a variability of Acetaldehyde dehydrogenase, such that it may not be effective, so acetaldehyde builds up--> flushing) |
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How much energy is produced from Proteins? Carbohydrates? Fat?
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Protein and Carbs: 4kcal
Fat: 1kcal |
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Ketone bodies are formed from the metabolism of what?
What are the ketone bodies? |
Fatty acids.
Acetoacetate and beta-Hydroxybutyrate. |