Questions and Answers
What is the concept of vitamins?
Vitamins are organic compounds essential for normal physiological functions and cannot be synthesized in adequate amounts by the body.
Which of the following are classes of vitamins? (Select all that apply)
What are vitamers?
Vitamers are different forms of a particular vitamin that are chemically related to one another and responsible for the physiological activity of a vitamin.
Vitamin C is also known as ______.
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Vitamins yield energy directly when consumed.
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What happens when there is a deficiency of a vitamin?
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Which of the following are recognized vitamins? (Select all that apply)
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What distinguishes vitamins from other nutrients?
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How are provitamins defined?
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Vitamin B1 is also known as ______.
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Study Notes
Course Overview
- Topics include definitions, classifications, food sources, functions, requirements, deficiency symptoms, and toxicity potential of vitamins.
Vitamins Defined
- Vitamins serve essential physiological functions but do not provide structural roles or significant energy through catabolism.
- Recognized as critical nutrients needed in small amounts, they must be activated metabolically for functional use.
Historical Context
- Early 20th Century discoveries indicated that growth failure in rats could be reversed by introducing small amounts of milk, highlighting the need for additional nutrients.
- The term "vitamine" was coined by Casimir Funk, derived from "vita" (life) and "amine," reflecting the chemical origins of the first identified vitamin.
Operating Definition of Vitamins
- Essential organic compounds not synthesized adequately by the body, leading to specific deficiency syndromes when lacking.
- Distinction from macronutrients through unique physiological functions and minimal required amounts.
Vitamin Caveat
- Certain substances function as vitamins for specific species only or under certain dietary conditions.
Vitamin Criteria
- Must not be synthesized sufficiently by the body.
- Chronic deficiency leads to observable physical symptoms, which can be restored by replenishing vitamin levels.
Recognized Vitamins
- A total of 13 substances are recognized as vitamins, which can be analogs grouped as families or precursors converted to active forms (provitamins).
- Notable vitamins:
- Vitamin A (retinols, beta-carotene)
- Vitamin B1 (thiamin)
- Vitamin B2 (riboflavin)
- Vitamin B3 (niacin)
- Vitamin B6 (pyridoxine)
- Vitamin B12 (cobalamins)
- Vitamin C (ascorbate)
- Vitamin D (calciferols)
- Vitamin E (tocopherols)
- Vitamin K (phylloquinones)
Differences Between Vitamins and Other Nutrients
- Vitamins differ structurally from carbohydrates, fats, and proteins as they exist as individual units and do not yield energy.
- Required in microgram quantities, with distinct roles as enzyme co-factors.
Vitamers and Provitamins
- Vitamers: Various chemical forms of a vitamin providing physiological activity.
- Provitamins: Substances converted into active vitamin forms post-absorption.
- Preformed vitamins: Exist in their active forms in foods.
Vitamin Classification by Solubility
- Fat-soluble Vitamins: Include A, D, E, and K, characterized by aromatic and aliphatic structures.
- Water-soluble Vitamins: Include B-complex vitamins and vitamin C, containing polar or ionizable groups.
Impact of Solubility
- Solubility affects digestion, absorption, transportation, storage, and excretion of vitamins.
Vitamin Stability
- Water-soluble vitamins susceptible to destruction by air, heat, light, water, and pH changes; generally less stable than fat-soluble vitamins.
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Description
This quiz covers the essential concepts of vitamins and their metabolic functions in the body. It includes questions on the different classes of vitamins, food sources, and the body's requirements. Test your knowledge on how vitamins contribute to overall health and metabolic pathways.
