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Introduction to Vitamins exam

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  • What are vitamins?
    Essential organic micronutrients required in small amounts for health.
  • Micronutrients
    Nutrients needed in small amounts, including vitamins and minerals.
  • How are vitamins different from minerals?
    Vitamins are organic (carbon-based); minerals are inorganic.
  • Fat-soluble vitamins
    Vitamins A, D, E, and K that dissolve in fat and are stored in body tissues.
  • How many essential vitamins are there?
    There are 13 essential vitamins needed by the human body.
  • Water-soluble vitamins
    B vitamins (8 types) and vitamin C, which dissolve in water and are not stored extensively.
  • Are vitamins a source of calories?
    No, vitamins are non-caloric and do not provide energy.
  • Provitamin
    An inactive precursor that must be converted to an active vitamin form in the body.
  • Preformed vitamin
    A vitamin in its active, usable form as found in food.
  • What is bioavailability?
    The percentage of a consumed vitamin that is absorbed and available for use in the body.
  • Which sources are typically less bioavailable: plant or animal?
    Plant-based vitamin sources are generally less bioavailable than animal-based sources.
  • Antioxidant
    A substance that protects cells from damage by free radicals.
  • Which vitamins act as antioxidants?
    Vitamins E and C function as antioxidants.
  • Free radical
    A highly reactive molecule with unpaired electrons that can damage cells.
  • What is oxidation in the context of vitamins?
    A chemical process where a substance loses electrons, potentially creating free radicals.
  • Why are some vitamin letters and numbers missing?
    Some were reclassified as not vitamins, and their designations were retired.
  • How are vitamin names (letters/numbers) assigned?
    Based on the order of their discovery.
  • Are all vitamins single molecules?
    No, most vitamins are groups of related molecules with the same function, except B7 and C.
  • What is the main function of vitamins in the body?
    To support various biological processes and maintain health.
  • Why is vitamin D considered essential even though the body can synthesize it?
    Because the body usually does not make enough, so dietary intake is needed.
  • What is a provitamin example?
    Beta carotene is a provitamin that is converted to vitamin A.
  • Which vitamin is found in egg yolk in its preformed state?
    Vitamin A (as retinol).
  • What does 'non-caloric' mean?
    Does not provide calories or energy.
  • Which vitamins are only required in small amounts?
    Micronutrients, including all vitamins.
  • What is the function of antioxidants like vitamin E?
    They donate electrons to free radicals, stabilizing them and preventing cell damage.
  • Which vitamin group includes thiamine?
    B vitamins (specifically, vitamin B1).
  • What is the bioavailability of beta carotene from spinach salad?
    About 30%.
  • What is the bioavailability of retinol from liver?
    About 80%.
  • Why are vitamins defined more by function than structure?
    Because most represent groups of molecules with the same biological function.