Biochem Exam 2 (3-4) – Flashcards

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where does the Pentose Phosphate Shunt happen?
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cytoplasm
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this is a product of PPP and it is necessary to make nucleotides and deoxynucleuotides
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Ribose-5-Phosphate
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this product of the PPP is primarily involved in reduction reactions and is most prominent in making fatty acids and dealing with oxidative damage
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NADPH
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in the liver, about ____% of liver glucose metabolism goes through the PPP but it is higher in places where you make ___________
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5-10 fatty acids (adipocytes)
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what does NADPH stand for?
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nicotinamide adenine dinucleotide-phosphate (Derived from Niacin)
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NADPH is prominent in synthesis of ______ and detoxification of
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fatty acid, cholesterol, neurotransmitter, nucleotide, reduction of oxidized glutathion e, cytochrome P450 monooxygenases
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thiamine containing enzyme that moves 2 carbon units and has been used to measure thiamine concentrations in people by measuring enzyme activity
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transketolase
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if you have a thiamine deficiency, you will develop ____________ which most often comes up in alcoholics and gives rise to ___________
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wernicke-korsakoff syndrome wet or dry beriberi
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what is the function of transaldolase?
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move 3 carbons
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the first committed step in the pathway, where regulation primarily occurs, is at _________
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glucose-6P to phosphogluconolactone by G6PDH
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in PPP, G6PDH is activated by _________ and deactivated by __________
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insulin NADPH
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since the kM of G6PDH is ______ than the concentration of [NADPH] in the committed step of PPP, this means that the reaction favors ___________ and must be inhibited
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less NADPH
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what are the names of the steps, in order, of oxygens oxidation states?
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molecular oxygen superoxide radical ion hydrogen peroxide hydroxyl radical
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what is the most reactive oxygen species? (can break DNA and lead to mutations in patients)
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hydroxyl radical
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superoxide reacts with hydrogen peroxide to produce hydroxyl radical
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haber-weiss reaction
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hydrogen peroxide reacts with iron to produce hydroxyl radical
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fenton reaction
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this is caused by a deficiency in NADPH oxidase and it results in multiple fungal infections and problems fighting pathogenic infection
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Chronic Granulomatous Disease
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hydrogen peroxide makes hydrochloric acid through ___________ which is also used to generate bleach
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myeloperoxidase
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what are the diseases thought to be associated with free radical injury?
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atherogenesis, ischemia (reperfusion injury), alcoholism, ALS, acute renal failure, emphysema
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this occurs after an ischemic attack and happens when the blood supply is restored suddenly, leading to a burst of oxygen and a shower of oxygen radicals
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reperfusion injury
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this is a major problem caused by peroxides because it disrupts membrane structures
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lipid peroxidation
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oxygen radicals can attack _____, _____, and ______
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lipids, carbs, proteins
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what vitamins/bioflaivonoids that can be used to protect ourselves from free radical damage?
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vitamin a, vitamin c, vitamin e, green tea, turmeric, chocolate
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this enzyme converts superoxide to hydrogen peroxide
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Superoxide Dismutase (SOD)
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_________ reduces peroxides into water and at the same time, it is oxidized into _______
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glutathione Peroxidase (GSH) GSS
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glutathione is a _________ containing enzyme and since it is ___________, it is responsible for the ________ environment of the cytoplasm of cells
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selenium reducing
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inside of the cell, _____ bonds are common and outside of the cell (also in the ER), ____ bonds are common
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SH SS
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NADPH produced by _____________ maintains the supply of glutathione needed to destroy peroxides
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glucose-6P-dehydrogenasee
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a deficiency in _________ is extremely common with a similar distribution as malaria and sickle cell anemia since they all affect red blood cells
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glucose-6-phosphate
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when you have a G6PDH deficiency, __________ form in RBC's when the cells are exposed to an oxidizing chemical in vitro. These form (like a precipitation of hemoglobin) due to the ________ bonds between hemoglobin molecules since there is not enough reducing activity to keep the hemoglobins in a ______ state
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heinz bodies disulfide SH
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these are immature RBC's often seen as a side effect in someone with a G6P DH deficiency
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Reticulocytes
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if you put _______ stress on a person who has a glucose-6-phosphate Dehydrogenase activity, there will be displayed symptoms. Situations that put this type of stress are...
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oxidative, sulfonamides, aspirin, NSAIDs, Quinine, Quinadine, Napthylene, Fava Beans
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in glucose-6-phosphate dehydrogenase deficiency, what change in the normal red blood cell leads to hemolytic anemia?
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decreased concentration of NADPH, defect in GSSG
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why are RBC's so sensitive to NADPH?
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they only have one way to make NADPH!
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why dont RBC's do the TCA cycle?
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they don't have a mitochondira
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glycogen is the main source of energy until about ____ hours of starvation in which ________ becomes the main source of glucose
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16 gluconeogenesis
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In Claude Bernard's Experiment, he concluded that dogs do not eat carbohydrates from looking at the portal vein which _______ the liver and has a _____ glucose conc and the hepatic vein which _______ the liver and has a _______ glucose conc
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enters low leaves high
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approximately 90 % of gluconeogenesis occurs in the ______, 10% in the ________ and the fraction of glycolysis increases in the _________ during starvation
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liver kidney kidney
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what are the precursors for gluconeogenesis?
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pyruvate, lactate, amino acids, glycerol
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this GNG precursor comes from pyruvate
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lactate
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this GNG precursor comes from pyruvate and TCA intermediates
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amino acids
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this GNG precursor comes from dihydroxyacetone phosphate
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glycerol
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the reaction of GNG that involves pyruvate carboxylase takes place in what sub-cellular location?
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mitochondria
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the reaction of GNG that involves glucose-6-phosphatase occurs in what sub-cellular location?
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ER
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what are the reactants of gluconeogenesis?
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2 Pyruvate, 4 ATP, 2 GTP, 2 NADH, 2 H
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what are the products of gluconeogenesis?
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glucose, 2 ADP, 2 GDP, 2 NAD+, 6 Pi
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oxaloacetate is converted to ______ or ______ to be transported out of mitochondria
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malate, aspartate
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in order to transport oxaloacetate out of the mitochondira, it has to be ________ to malate in the mitochondria and then ________ back to oxaloacetate in the cytoplasm
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reduced oxidized
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the mitochondria has a _______ environment and the cytoplasm has a ___________ environment
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oxidizing reducing
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oxaloacetate is converted to aspartate in the mitochondria via __________ from glutamate and then converted back to oxaloacetate in the cytoplasm by ____________
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transamination cytoplasmic transaminase
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the cofactors necessary for pyruvate carboxylase activity are _______, _______, and _______ ions and the activator necessary is ________
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biotin, magnesium, manganous, acetyl CoA
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Biotin is covalently attached to __________. When it is attached, it functions as a carrier of _________
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carboxylase protein activated CO2 (HCO3-)
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this binds biotin with a high affinity and therefor can prevent pyruvate carboxylase from converting pyruvate to oxaloacetate
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avidin
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what proteins are involved in Glucose-6-Phosphatase's complex function?
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phosphatase, translocase 1, translocase 2
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this subunit of G6Pase is on the side of the membrane that is not in direct contact with the cytoplasm. It catalyzes hydrolysis of G6P to glucose
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phosphatase
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this subunit of G6Pase mediates transport of glucose-6-phosphate from the cytoplasm to the opposite side of the ER membrane, where the phosphatase enzyme is located
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T1 (translocase 1)
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this subunit of G6Pase mediates transport of the phosphate back to the cytosol
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T2 (translocase 2)
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these are the only cells able to convert G6P back to Glucose aka the only cells with glucose-6-phosphatase activity. They are responsible for returning glucose back to circulation after its absorption from portal blood, intestinal lumen, or glomerular filtrate.
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liver, intestine, kidney .
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how is glucose-6-phosphatase in the liver different from others?
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maintains blood glucose levels, maintains supply of glucose to other tissues, rate of catalysis depends on substrate supply, not regulated by feedback inhibition
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pyruvate dehydrogenase converts pyruvate to _______ and is inhibited by ________ and _________
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Acetyl CoA NADH ATP
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pyruvate carboxylase is stimulated by high levels of __________ and ________
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pyruvate, Acetyl CoA
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pyruvate dehydrogenase is ___________ by insulin and _________ by phosphorylation of serine at its E1a subunit
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activated inhibited
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Fructose-1,6-bisphosphatase is inhibited by _________ and ________ and activated by _________
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AMP F-2,6-Bisphosphate Citrate
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conversion of PEP to Glucose is ______ by Glucagon and ________ by Insulin
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activated inhibited
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Pyruvate Carboxykinase is . activated by _______ and ________ and inhibited by _______
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glucagon steroids insulin
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Insulin targets ______ but Glucagon does NOT
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muscle
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Insulin targets ______ metabolism but Glucagon does NOT
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protein
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in gluconeogenesis, PFK2 is _______ when it is phosphorylated
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activated
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glucocorticoids increase the synthesis of __________ and __________
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PEP carboxykinase, glucose-6-phosphatase
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this is the process of transporting lactate from muscle and erythrocytes to the liver for re-synthesis of glucose. This process means that erythrocytes and muscles can . use glycolysis efficiently since they don't have to supply the energy for glucose!
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Cori Cycle
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this is when pyruvate in the muscle is transaminated into Alanine, brought to the liver, and transformed back into pyruvate, giving off its amino group for another transamination reaction
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Cahill Cycle
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what are the major metabolic problems of individuals with deficiencies . in gluconeogenic enzymes?
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hypoglycemia, acidosis (from build up of substrates such as lactate, pyruvate, and alanine)
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what are the symptoms associated with hypoglycemia or acidosis from metabolic problems with individuals in gluconeogenesis?
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adrenergic effect responses (anxiety, sweating, heart palpation) or neuroglycopenia (confusion, coma, seizures, death)
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