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43 Cards in this Set
- Front
- Back
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What sugar does Vitamin C closely resemble? |
Glucose |
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Which enzyme do Humans lack to make vitamin C on their own? |
Gulnolactone oxidase |
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Only metabolically active isomer of Vit C? |
L Isomer |
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This form of Vit C is found in food |
Ascorbic acid |
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This form of Vit C is ionic |
Ascorbate |
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This form of Vit C is oxidized form found in two low levels |
Dehydroascorbic acid (DHA) |
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Is the main transporter responsible for Vit C absorption in the SI |
SVCT1 |
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SVCT1 moves molecules in which direction? |
Symporter- same |
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What downregulates SVCT1? |
Ascorbic acid |
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Does Vit C require digestion prior to absorption? |
No |
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Where does Vit C Digestion occur? |
In the SI across the brush border in the Illeum Jejunum |
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The oxidized form DHA, is absorbed by ______ and what numbers? |
GLUT 1 & 3 |
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What converts DHA back to ascorbic acid in the cell? |
Dehydroascorbic acid reductase |
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Ascorbic acid is the _____ form DHA is the ______ form |
Reduced Oxidized |
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A factor influencing the absorption is |
Intake. The more that is taken in the less is absorbed |
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Transport of ascorbic acid by SVCTs is |
Sodium dependent |
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True or false: Ascorbic acid can cross the blood-brain barrier? |
False |
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Where does Vit C enter after absorption? |
Cerebrospinal fluid through SVCT2 in the choroid plexus |
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DHA crosses the Blood-Brain barrier via? |
GLUT1 |
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There is more ascorbic acid in the organs or blood? |
Organs |
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In the kidney Ascorbic acid is excreted by and reabsored by? |
Glomerular filtration Reabsorption mediated by SVCT1 in the apical membrane No significant DHA reabsorption |
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Vit C acts as an antioxidants through _____ reactions and ___ |
Enzymatic Regeneration of other antioxidants |
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Vit C acts as a ________ factor to maintain Cu or Fe in its active state |
Reducing |
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Made of 3 polypeptides synthesize by firboblasts to form triple helix in ER |
Collagen |
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Hydroxylation of ____ and _____ are post translational mods that occur in ER |
Proline and Lysine |
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Hydroxylation in collagen syn. allows for what? |
Crosslinking of the 3 chains |
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Addition of ___ group allows further post-translational mods i.e. phosphorylation and glycosylation |
OH |
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Important for the transport of long-chain FAs to the mito for B-OX |
Carnitine |
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______ is required for 2 hydroxylation steps in carnitine syns. |
Vit C |
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Which two enzymes in Carnitine syn. require Vit C? What does Vit C convert between? |
Trimethyl lysine hydroxylase Butyrobetaine hysroxylase Converts Fe3 to Fe2 |
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__________ take a free radical electron to complete its ring |
Antioxidants |
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Unbalance between the antioxidant capacity and the generation of ROS (Reactive Oxygen Species) |
Oxidative stress |
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Convert superoxide to hydrogen peroxide |
SOD1 and SOD2 |
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Peroxidases that convert hydrogen peroxide to water |
Catalase and GPX |
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Vit C acts as an antioxidant by |
Donating electrons to free radicals Reducing Vit E |
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ViT C acts as a _____ by reducing transition metals |
Pro-oxidant Cu2--> Cu1 Fe3-- Fe2 |
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Vit C enhances the immune system and destroys ____ |
Histamin |
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Increased intake of fruits and veggies are linked with decreased risk of some ____ |
cancers |
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Vit C increases the absorption of non heme ____ in the SI |
Iron |
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Results from inadequate Vit C, < 10mg/day. Four H's |
Scurvy. Hemorrhagic signs Hyperkeratosis Hypochondriasis Hematologic abnormalities |
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Toxicity: __g per day or more causes ab pain and diarrhea, kidney stones, iron toxicity |
2 |
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Who was awarded the Nobel Prize in Physiology/Med? |
Albert Azent-Gyorgyi |
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Who was awarded the Nobel Prize in Chem? |
Walter Haworth |
