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56 Cards in this Set
- Front
- Back
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What is the first irreversible step/enzyme in gluconeogenesis? Where?
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1. Pyruvate carboxylase converts Pyruvate to OAA in mitochondria
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What is the next irreversible step/enzyme in gluconeogenesis? Where? what is needed?
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OAA -> PEP by PEP carboxykinase in the CYTOSOL; requires GTP
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What is the next irreversible step/enzyme in gluconeogenesis? Where?
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F1,6-bisphosphate -> Fructose6P by F1,6Bisphosphatase; in the cytosol
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What is the last irreversible step/enzyme in gluconeogenesis? Where?
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Glucose-6-P -> Glucose by Glucose 6 phosphatase; in the Endoplasmic Reticulum!!
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What is an acronym for the 4 enzymes required for the irreversible steps of gluconeogenesis?
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Pathway Produces Fresh Glucose
-Pyruvate Carboxylase -PEP carboxykinase -F16Bisphosphatase -Glucose6Phosphatase |
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What TISSUES contain the enzymes required for MAKING glucose via gluconeogenesis?
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-LIVER
-KIDNEY -INTESTINAL EPITHELIUM |
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What tissue is INCAPABLE OF making glucose?
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Muscle
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What will a deficiency in one of these key enzymes result in?
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Hypoglycemia
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What is the pathway that produces NADPH?
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HMP shunt - the Pentose Phosphate Pathway
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And what are 3 processes NADPH required for?
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-Steroid biosynthesis
-Fatty acid biosynthesis -GSH reductase in RBCs |
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WHERE does the HMP shunt occur?
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ALL reactions are in the CYTOSOL
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Does anything happen with ATP in the HMP shunt?
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nope
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What are 3 tissues where the HMP shunt is active?
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-Adrenals (steroid synth)
-Liver -Lactating breast |
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What are the 2 types of reactions in the HMP shunt? Which is reversible?
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-oxidative - nonreversible
-nonoxidative - reversible |
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What is the key enzyme in the OXIDATIVE/NONREVERSIBLE step of the HMP shunt? Product?
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G6P Dehydrogenase - Produces NADPH!
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And what is NADPH for?
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-Steroid synthesis
-Fatty acid synthesis -Glutathione reduction -Cytochrome P450s |
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What enzymes catalyze the NONoxidative, REVERSIBLE step in the HMP shunt? What are the products?
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Transketolases
Produces Ribose-5-Phosphate, G3P, and F6P |
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What cofactor do Transketolases require?
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Thiamine
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What is Ribose-5-P required for?
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Nucleotide synthesis
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What are G3P and F6P?
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Glycolytic intermediates
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What is the RLS step enzyme in the HMP?
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G6PD! glu-6phosphate dehydrogenase
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What does G6PD deficiency cause?
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Hemolytic anemia
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Why does G6PD deficiency cause hemolytic anemia?
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Because lack of it means GSH is not kept reduced, so free radicals build up
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What are 3 oxidizing agents that will exacerbate hemolytic anemia caused by G6PD deficiency?
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-Fava beans
-Sulfonamides -Primaquine -Tuberculosis drugs |
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In what race is G6PD deficiency more prevalent?
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Blacks
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What can be seen in RBCs that are deficient in G6PD?
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Heinz bodies
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What are Heinz bodies?
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Hemoglobin precipitates
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What is the INHERITANCE of G6PD deficiency?
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X-linked recessive!
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Why is G6PD deficiency more prevalent in blacks?
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Confers resistance to MALARIA
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What is FRUCTOSE intolerance caused by?
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Hereditary deficiency of ALDOLASE B
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What is the inheritance pattern of ALDOLASE B deficiency?
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Recessive (its a metabolic disorder)
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What accumulates in Aldolase B deficiency and what is the result?
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Fructose-1-P builds up and depletes ATP availability; inhibits Glycolysis and Gluconeogenesis!
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What are 4 symptoms of Fructose intolerance?
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-Hypoglycemia
-Jaundice -Cirrhosis -Vomiting |
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What is the treatment for Fructose intolerance?
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Decrease intake of Fructose and Sucrose!
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What is Sucrose?
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Glucose + Fructose
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What is Essential Fructosuria?
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A benign asymptomatic disorder of increased Fructose in urine due to a defect in Fructokinase
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What enzyme is deficient in Galactosemia?
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Galactose-1-phosphate uridyltransferase
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3 Symptoms of Galactosemia:
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-Mental retardation
-Hepatosplenomegaly -Cataracts |
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What are the symptoms of Galactosemia caused by?
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Accumulation of Galactose-1P and Galactitol which are toxic
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What is the treatment for Galactosemia?
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Exclude Galactose and lactose from the diet
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What is lactose?
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Galactose + Glucose
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What will deficiency of Galactokinase cause?
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Buildup of Galactose and Galactitol in serum and urine
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What is LACTASE deficiency?
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The hereditary or age-dependent intolerance to lactose due to loss of the brush border enzyme
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3 sx of Lactase deficiency:
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-Cramps
-Osmotic diarrhea -Bloating |
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2 treatments for Lactase deficiency:
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-Avoid lactate
-Lactase pills |
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What are the essential amino acids?
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PVT TIM HALL
-Phe, Val, Thr -Tryp, Ile, Met -His, Arg, Leu/Lys |
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What are the ketogenic essential amino acids?
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Leu and Lys
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What are the Glucogenic/ketogenic AA's?
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PIT
Phe, Ile, Trp |
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What are the Glucogenic AA's?
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MATHV
Met, Arg, Thr, His, Val |
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What 2 AA's are essential during periods of growth?
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Arg and His
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What are 2 acidic AA's?
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Asp and Glu
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What are Aspartate and Glutamate at body pH?
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Charged
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What are the 3 basic AA's?
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Arginine
Lysine Histidine |
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Which basic aa is most basic?
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Arginine
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Which basic AA is not charged at body pH?
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Histidine
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Which aa's are high in histones? Why?
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Arginine and lysine - they bind neg charged DNA.
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