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14 Cards in this Set
- Front
- Back
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What is vitamin C the generic descriptor factor for? |
It is the generic descriptor for all compoundsexhibiting qualitatively the biological activity of ascorbic acid. |
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What are the two forms of Vitamin C?
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Ascorbic acid and dehydroascorbic acid (oxidizedform) (double present). |
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Where is Vitamin C found? |
Vitamin C is widely found in both plants andanimals, occurring as both ascorbic acid and dehydroascorbic acid (oxidizedform) (double present). It can be acquired from dietary sources ofplants and animals. In foods, Vitamin C is mostly as ascorbic acid,but a small amount is also in the dehydroascorbic acid form. |
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Can we make Vitamin C? Why or why not? What can make Vitamin C and why? |
Ascorbic acid is a 6-carbon compound derivedfrom glucose, but humans cannot make it due to the lack of gluconolactoneoxidase, the last enzyme in the Vitamin C synthetic pathway. Plants have theenzyme, gluconolactone oxidase, and can convert glucose into ascorbic acid. |
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What is the stability of Vitamin C like? |
Vitamin C is destroyed by heat, light, oxidationand alkaline solutions but stable in acidic solutions. Cooking and storage may affect the Vitamin Ccontent of foods. For practical reasons, fruits are a good sourceof Vitamin C as they are generally eaten raw. Ingestion of Iron or Copper with Vitamin C mayalso cause oxidative destruction of Vitamin C. |
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Does Vitamin C need digestion prior to absorption? |
Vitamin C does not require digestion in orderfor it to be absorbed into the enterocytes. |
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How does Ascorbic acid enter the enterocyte? |
Ascorbic acid absorption occurs through Na+-dependentVitamin C transporters (SVCT) 1 and 2. |
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How does Dehydroascorbic acid enter the enterocyte? |
Dehydroascorbic acid absorption occurs throughglucose transporters- mainly GLUT 1 and 3 –once absorbed into the enterocyte,dehydroascorbic acid is recycled into ascorbic acid by the enzymedehydroascorbic acid reductase. |
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What is the intake of vitamin C like? |
70-90% of Vitamin C is absorbed if the dietaryintake of Vitamin C is within 30-180 mg/day. |
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What happens at higher intake of Vitamin C? |
Absorption is drastically reduced with higherintakes- ex: Only 16% is absorbed at high intakes (approx. 12g/day). |
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How is Vitamin C transporter in the blood? |
Vitamin C is transported freely in the blood andor bound to the protein albumin. |
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What is the blood Vitamin concentration range? |
Normal blood plasma ascorbic acid concentrationranges from 0.4-1.7 mg/dL. |
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Where is Vitamin C most found in? Where else is Vitamin C found? |
In tissues, highest concentration of Vitamin C isfound in the adrenal and pituitary glands (30-50 mg/100g of wet tissue), alsoeyes, brain and red blood cell. Tissues with intermediate levels of Vitamin Care the liver, spleen, heart, kidneys, lungs, pancreas, and muscle. |
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Vitamin C was initially associated with what? |
Scurvy
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