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72 Cards in this Set
- Front
- Back
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What is the Km difference between gluokinase and hexokinase?
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Glukokinase: High Km, low affinity, high capacity
Hexokinase: Low Km, high affinity, low capacity. |
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Name three ways to decrease blood cholesterol levels.
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1. Statins
2. Lifestyle, cholesterol/fat intake. 3. Decrease LDL receptors |
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What are the metabolic effects of LXR?
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Liver X receptors; Regulate cholesterol homeostasis, glucose homeostasis and FA homeostasis. They are nuclear receptors.
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What is the enzyme in carbohydrate metabolism that is responsible for regulating insulin secretion from Pancreatic B-cells?
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Glucokinase
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What happens to the rate of glycolysis during hypoxia?
(increase/decrease/not sure) |
Decrease
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What enzyme determines the rate of glycolysis in this state?
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Lactate dehydrogenase
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What regulates this (hormone) – must mean enzyme, or what hormones regulate it?
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NADH/NAD ratio.
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What are the allosteric activators and inhibitors of PFK-1?
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Activators; Fr-2,6-BP and AMP
Inhibitors; ATP, Citrate |
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What enzyme produces GTP in the TCA?
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Succinyl-CoA synthase/succinyl thiolase
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What are the substrates, products and coenzymes of methylmalonyl CoA racemate?
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D-methylmalonyl Coa → L-methylmalonyl CoA.
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What are the substrates, products and coenzymes of methylmalonyl CoA mutase?
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L-methylmalonyl CoA → Succinyl CoA.
Coenzyme; Vit B12. |
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What are the substrates and products of PDH?
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Pyruvate + CoA-SH + NAD → AcetylCoa + NADH + C02
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What organs, tissues primarily use glucose from glycolysis for energy?
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Skeletal muscle, brain, RBC.
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What organs will be affected by glycogen storage disease?
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Liver and Skeletal muscle.
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Name an inhibitor of mitochondrial ATP synthase
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Oligomycin
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What are the substrates, products and cofactors for IMP dehydrogenase?
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IMP + H2O + NAD → Xanthosine monophosphate + NADH + H+
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What is the major protein for LDL?
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Apo B-100
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Explain the monosaccharide unit/bond between them in Glycogen
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Glucose units, linked a(1 4) in glycosidic bonds. Branches with a(1 6) glycosidic bond
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Explain the monosaccharide unit/bond between them in sucrose
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Components are Glucose and Fructose linked by glycosidic bond, ether bond from C1 on glucose and C2 on fructose.
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Explain the monosaccharide unit/bond between them in lactose
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Components are glucose and galactose linked by glycosidic B (1 4) bonds
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Position of OH group in primary bile acids
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Hydroxyl at 3, 7 and 12 position
(in the deoxy bile acids only at 3 and 7 |
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What is the substrate, product and coenzyme of Threonine dehydratase
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Threonine → a-ketobutyrate + NH3
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What is the substrate, product and coenzyme of IMP dehydrogenase
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IMP + NAD + H2O → Xanthosine momophosphate + NADH + H+
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What is the substrate, product and coenzyme of Glycogen phosphorylase
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Glycogen + Pi → Glucose – 1 – Phosphate.
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What are precursors of LDL? Via what enzyme?
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Precursors IDL
Enzyme is hepatic lipase. |
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What are PFK-1 Activators and inhibitors?
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Activators, AMP and Fr 2,6 BP
Inhibitors, ATP and Citrate |
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How many ATP can be made from the citric acid cycle?
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3 NADH can give 7.5 ATP
1 FADH can give 1.5 1 GTP produced. Ca 10 ATP |
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What is the intermediate in FA synthesis? Prosthetic group? *must mean fatty acid synthase.
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Prosthetic groups are Phosphopantethein residue and cysteine residue.
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What enzyme in FA synthesis reduces NADPH
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B-ketoacyl reductase and crotonyl reductase (enzyme step 3 & 5)
(enoyl reductase will oxidise NADP) |
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What is the cofactor of complex 1 in oxidative phosphorylation?
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FMN, Fe-S and NADH dehydrogenase.
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What does PP1 do?
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When it is phosphorylated (glucagon) it will phosphorylate glycogen phosphorylase (activate) and glycogen synthase (inactivate)
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What does phosphoglucomutase do?
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Glucose-1-P → glucose-6-P.
It is a transfer or interconversion of where P sits. |
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Which enzyme in the glucose metabolism is in the ER membrane?
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Glucose-6-Phosphatase
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What happens to fatty acids in the intestine lumen.
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LCFA – taken up via chylomicrons
MCFA – directly absorbed |
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Terminal electron acceptor of electron transport chain?
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oxygen
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What is hormone sensitive lipase? Where is it found? What is its substrate and product?
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Found in adipose tissue.
Will hydrolyze TAG → Free fatty acids. |
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Bile acids, where are the OH group, and what is its configuration?
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Hydroxyl group found on 3,7 (and 12). Configuration is that the OH- groups are pointed upwards (same way as carbon tail), so that it is amphipatic.
important for emulgatic function of Bile salts. |
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What is the substrate, product and cofactor of threonine dehydratase?
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Threonine → a-ketobutyric acid + NH3
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What is the substrate, product and cofactor of mehtylmalonyl CoA mutase?
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L-methylmalony coa → succinyl-CoA
Cofactor is Vit B12 |
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What is the committed step of glycolysis?
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Fructose-6-P → fructose-1,6-P
Enzyme is PFK-1 |
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What are the enzymes that yield NADH in the TCA?
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Isocitrate dehydrogenase
a-ketoglutarate dehydrogenase malate dehydrogenase. |
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Which coenzymes are needed for bile acid synthesis?
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Cytochrome P-450
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Explain the monosaccharides in the following compounds, and their linkage (3 points):
- Glycogen - Sucrose - Lactose |
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Where is LXR (liver X receptor) located?
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LXRα - Mainly liver, kidney, intestines, adipose tissue, macrophages, spleen and lungs.
LXRβ - Almost all tissues. |
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Draw the reaction of Thr dehydratase + Coenzyme
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Threonine → Alpha-Ketobutyrate + NH4+
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Precursor of LDL and which enzyme is responsible for this transformation?
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IDL and VLDL, degraded by hepatic lipase
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2 enzymes in Glycolysis that create product with high group transfer potential (not ATP!!)
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- Glyceraldehyde 3-phosphate dehydrogenase (Glyceraldehyde 3-phosphate → 1,3 bisphosphoglycerate, hig E acyl-P).
- Enolase (2-phosphoglycerate → Phosphoenol pyruvate, high E enolic-P). |
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Which hormone activate FA release from the adipose tissue?
Which enzyme is phosphorylated? |
Glucagon → PKA → Phosphorylate Hormone sensitive lipase (HSL) → Cleaves fatty acids from triacylglycerols in the adipocytes (at C1 and C3).
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Cofactor of glycogen phosphorylase
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PLP (pyrodoxal phosphate/active vit B6)
glycogen + Pi → glycogen + glucose-1-P |
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Which reaction does UMP synthase catalyze, and which cofactors are used:
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UMP synthase is also called orotidine 5’-phosphate decarboxylase. It catalyzes the following reaction:
Orotidine monophosphate → Uridine monophosphate + CO2. |
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Which reaction does phosphoribosyl pyrophosphate synthetase catalyze:
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Ribose 5-phosphate + ATP → Phosphoribosyl pyrophosphatase + AMP.
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Glutaminase
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Glutamine + H2O → Glutamate + NH4+.
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What are the receptors involved in the pathomechanism of atherosclerosis?
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PCSK9, ScavengerR, LOX-1 (?)
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Enzyme related to Andersen disease:
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Andersen disease is the name for glycogen storage disease type IV (amylopectinosis). The enzyme which is deficient is amylo-1,4-1,6-transglucosidase.
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What is the reaction with aspartate catalyzed by aminotransferase, what is the cofactor.
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Aspartate + α-Ketoglutarate → Oxaloacetate + Glutamate. Cofactor is pyridoxal phosphate.
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Which enzyme catalyzes the reaction where acetyl CoA are joined with oxaloacetate:
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Citrate synthase.
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Where are the hydroxyl groups located on bile acids, and in which direction are they (and why):
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3, 7 and 12. In an outward position to get a polarized appearance – emulsifying effect.
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How is cholesterol transported to the extrahepatic tissue:
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VLDL.
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Which molecules in the glycolysis have higher group transfer potential than ATP.
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Phosphoenolpyruvate, 1,3-Bisphosphoglycerate.
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Deficiency of which enzyme cause McArdles disease?
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Glycogen phosphorylase in skeletal muscle
during excersize -> no glucose -> no glycolysis -> no lactate -> no ph drop => painful cramps |
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Genetic mutation of which enzyme cases hereditary fructose intolerance?
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deficiency of Aldolase B (liver)
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Intake of which dietary constituents provoke the symptoms of hereditary fructose intolerance?
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*
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Which enzyme is defective in essential fructosuria?
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fructokinase (=> high fructose conc)
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List the names of the enzymes which are necessary to convert citrulline to ornithine!
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(urea cycle) arginine succinate synthase, arginine succinate lyase, arginase
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Name the substrates, products and coenzymes of
n-acetyl glutamate synthetase! |
NH3+Co2 -> Carbamoyl-P, coenzyme carbamoyl synthetase I (CPS1) (?)
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Name the Sub, enz, (if) coenz of glutamate DH
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a-ketoglutarate -> glutamate, by oxidative deamination
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Name the sub, enz, (if) coenz of alanine amino transferase!
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Pyruvate + NH3 -> alanine, PLP coenzyme
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Name all the lipoproteins transporting lipids in the circulation in theorder of the smallest to the highest density!
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-chylomicron
-VLDL -LDL -HDL -IDL |
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What are the major intracellular target of statins?
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*
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Give the names of the ketone bodies that are synthesized in the human body!
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acetone, acetoacetate, B-hydroxybutarate
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How many FADH2 are produced by 1mol palmitate?
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palmitate = c16, so 14FADH(x2), 7 NADH (x3), 8 AcCOa(x12)
-> 14 FADH, 96 AcCOa, 21 NADH => 131 ATP (-2ATP for FA activation) => 129 ATP |
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Which enzymes perform substrate level phosphorylase in the glycolysis (2 points)
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1st: phosphoglycerate kinase, 2nd: Pyruvte kinase
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