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42 Cards in this Set
- Front
- Back
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What is the other name for vitamin K1?
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Phylloquinone
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What is one of the primary functions of Vit K?
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Blood-clotting cofactor
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What type of molecules compose the Vit K family?
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Polyisoprenoid-substituded naphthylquinones
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What exactly does Vit K do?
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Functinos as a cofactor for post=translational modification of coag factors.
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Which pathway is vit K-dependent?
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Extrinsic
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What is the function of Vit K in the extrinsic pathway?
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Gamma-carboxylation Glutamic acid residues on Fx 2, 7, 9, 10
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What enzyme is Vit K a cofactor for?
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Y-Glutamylcarboxylase
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Where does Y-Glutamylcarboxylase modify the Coag factors?
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At 9-12 Glutamate residues on the N-terminal portions.
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What else does Y-Glutamylcarboxylase act on other than clotting factors?
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-Bone proteins
-Matrix proteins |
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How does the carboxylation of G-glutamyl residues activate clotting factors 2/7/9/10?
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It allows them to bind to Phosphatidyl Serine on platelets thru a Ca2+ Bridge.
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What are coag protein complexes composed of?
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1. Proenzyme (Fx II or V)
2. Activator (IXa or Xa) 3. LMWBP (V or VIII) |
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What happens to Vit K during the y-carboxlation reaction?
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It gets convered to an epoxide
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What reduces the epoxide form of Vit K back to its original form?
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Vit K Epoxide Reductase
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What targets Vit K Epoxide Reductase?
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Dicoumarol and Warfarin (anticoagulant drugs)
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What are the 2 major symptoms of Vit K dficiency?
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-Prolonged bleeding
-Easy bruising |
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3 Main general functions of Vitamin C:
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1. Protein modification
2. Coenzyme 3. Antioxidant |
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3 Enzymes that Vit C acts as a cofactor for:
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1. Prolyl Hydroxylase
2. Lysinyl Hydroxylase 3. Dopamine B-hydroxylase |
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What are Prolyl Hydroxylase
and Lysinyl Hydroxylase for? |
Collagen post-translational modification
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What is Dopamine B-hydroxylase for?
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Norepinephrine synthesis.
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How many electrons can Ascorbate accomadate as an antioxidant?
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1 or 2
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What 2 enzymes recycle oxidized Vit C?
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1. Ascorbate Free radical reductase
2. Dehydroascorbic acid dehydrogenase |
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For which radicals is Vit C a scavenger?
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-Singlet oxygen
-Peroxy radicals -Superoxide -Hydrogen peroxide |
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What metal element is Vit C essential for?
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Iron - it reduces ferric iron to ferrous state.
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What disease is caused by Vit C deficiency?
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Scurvy
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For which 3 physiological processes is Vit C essential?
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1. Collagen synthesis
2. Tyrosine degradation 3. Catecholamine synthesis |
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What enzyme for Tyrosine degradation is Vit C used?
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p-Hydroxyphenylpyruvate Dioxygenase
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What transports IRON in the bloodstream?
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Transferrin
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How is iron stored?
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As rust inside ferritin in the liver.
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How many iron molecules are stored in the ferritin core?
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Up to 4800
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What enzymes contain iron-sulfur complexes?
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-Aconitase (TCA cycle)
-Oxidases -ETC enzymes |
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What are the important heme proteins (4)?
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1. Hemoglobin
2. Myoglobin 3. Cytochromes 4. Aldehyde oxidase |
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What results from iron
-Deficiency -Excess |
Defic: anemia
Excess: hemosiderosis |
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What vitamins are antioxidants?
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-B-Carotenes
-E -C |
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What type of molecule is the Vitamin E family made up of?
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Tocopherols (eight exist)
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What is the most active for of Vitamin E?
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a-Tocopherol
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What is the primary antioxidant fuction of Vit E?
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Prevention of oxidation of PUFAs in membranes by
-Molecular oxygen -Free radicals -Peroxides |
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What cells are especially protected by Vit E?
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Erythrocytes
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What recycles oxidized Vit E?
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Vit C
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Other than serving as an antioxidant what does Vit E do?
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-Regulates enzymes
-Regulates gene expression |
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What enzymes are regulated by Vit E?
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-Signal transduction enzymes
-Protein C kinase -Phosphoprotein Phosphatase 2A -Diacylglycerol kinase -Lipoxygenase/Cyclooxygenase |
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What genes are regulated by Vit E?
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-A-tropomyosin
-Scavenger receptors |
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What is the major effect of Vit E deficiency?
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Fragility of RBCs
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