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Questions and Answers
Which vitamins are classified as fat-soluble vitamins?
Which vitamins are classified as fat-soluble vitamins?
What is a primary source of active vitamin A?
What is a primary source of active vitamin A?
Which function does vitamin A primarily serve in the body?
Which function does vitamin A primarily serve in the body?
Which vitamin acts as a precursor to vitamin A from plant sources?
Which vitamin acts as a precursor to vitamin A from plant sources?
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What is a primary effect of vitamin A deficiency?
What is a primary effect of vitamin A deficiency?
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Which vitamin is primarily responsible for the function of rod cells in dim light vision?
Which vitamin is primarily responsible for the function of rod cells in dim light vision?
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What condition may result from a deficiency of vitamin A in the eye?
What condition may result from a deficiency of vitamin A in the eye?
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Which of the following vitamins does NOT yield energy but facilitates energy-yielding reactions?
Which of the following vitamins does NOT yield energy but facilitates energy-yielding reactions?
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What is one of the roles of retinoic acid in the body?
What is one of the roles of retinoic acid in the body?
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Which function is primarily associated with water-soluble vitamins?
Which function is primarily associated with water-soluble vitamins?
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Where can vitamin D3 be primarily obtained from?
Where can vitamin D3 be primarily obtained from?
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Which of these vitamins is primarily obtained from animal sources?
Which of these vitamins is primarily obtained from animal sources?
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Which of the following is a symptom of vitamin A deficiency?
Which of the following is a symptom of vitamin A deficiency?
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How is vitamin D3 synthesized in the skin?
How is vitamin D3 synthesized in the skin?
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What effect does retinoic acid have on bone health?
What effect does retinoic acid have on bone health?
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Which of the following fruits is known for its high levels of carotenes?
Which of the following fruits is known for its high levels of carotenes?
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What condition is primarily caused by hypercalcemia due to abnormal calcification?
What condition is primarily caused by hypercalcemia due to abnormal calcification?
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Which type of tocopherol is known to be the most potent?
Which type of tocopherol is known to be the most potent?
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What is the primary dietary source of Vitamin K1?
What is the primary dietary source of Vitamin K1?
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Which of the following is NOT a function of Vitamin E?
Which of the following is NOT a function of Vitamin E?
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What factor can lead to a deficiency of Vitamin K?
What factor can lead to a deficiency of Vitamin K?
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Which is true regarding the active forms of Vitamin A?
Which is true regarding the active forms of Vitamin A?
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What role do rods play in vision?
What role do rods play in vision?
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What forms rhodopsin in the eyes?
What forms rhodopsin in the eyes?
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Where is vitamin D primarily stored in the body?
Where is vitamin D primarily stored in the body?
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What enzyme in the liver hydroxylates vitamin D3 to 25-(OH)-D3?
What enzyme in the liver hydroxylates vitamin D3 to 25-(OH)-D3?
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Which hormone stimulates the synthesis of calcitriol in the kidney?
Which hormone stimulates the synthesis of calcitriol in the kidney?
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What does a decrease in blood calcium levels stimulate?
What does a decrease in blood calcium levels stimulate?
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Which of the following is NOT a function of active vitamin D (Calcitriol)?
Which of the following is NOT a function of active vitamin D (Calcitriol)?
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What condition is caused by vitamin D deficiency in young children?
What condition is caused by vitamin D deficiency in young children?
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Which of the following is a common cause of vitamin D deficiency?
Which of the following is a common cause of vitamin D deficiency?
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What can lead to vitamin D toxicity?
What can lead to vitamin D toxicity?
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Study Notes
Biochemistry of Vitamins
- Vitamins are organic compounds
- They are essential for human health and growth
- Vitamins are required in small amounts
- Deficiency of a vitamin can result in a specific nutrition deficiency disease
- Vitamins are not synthesized in the human body, must be obtained from the diet
- Vitamins do not participate in tissue structure like carbohydrates, fats, and proteins
- Vitamins do not yield energy, but facilitate energy-yielding chemical reactions
- Vitamins act as coenzymes
- Vitamins are classified based on their solubility into two main groups: fat-soluble and water-soluble
- Fat-soluble vitamins include vitamins A (ADEK)
- Water-soluble vitamins include the B vitamins and vitamin C
Fat-Soluble Vitamins
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Vitamin A (retinol, retinal, retinoic acid)
- Active forms of vitamin A are retinol, retinal, and retinoic acid.
- Sources: Animal sources (meat, liver, milk, butter, egg yolk, fish liver oils) as retinol esters; plant sources (carrots, sweet potatoes) as carotenoids. α, β, γ-carotenes are important carotenoids, with β-carotene having the highest activity.
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Functions:
- Vision (rhodopsin in rods for dim light, iodopsin in cones for bright light)
- Supports normal growth of bones and teeth
- Role in reproduction in males and females
- Immunostimulant
- Anticancer agent, due to antioxidant properties
- Deficiency: Night blindness, xerophthalmia (cornea drying), growth retardation, increased susceptibility to cancer and anemia, rough skin (xeroderma), and mucous membrane problems of urinary, genital, gastrointestinal, and respiratory tracts leading to infections.
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Vitamin D (cholecalciferol/ergocalciferol)
- Sources: Provitamin 7-dehydrocholesterol in animals and man; ergosterol in plants, converted to vitamin D3 (cholecalciferol) by UV exposure and vitamin D2 (ergocalciferol) by UV exposure
- Active form: calcitriol (1,25-dihydroxycholecalciferol) is formed in the liver and kidney by enzymatic hydroxylation
- Functions: Essential for calcium and phosphorus absorption in the intestines and bone mineralization.
- Deficiency: Rickets in children and osteomalacia in adults.
- Regulation: Controlled by parathyroid hormone (PTH) and blood calcium and phosphate levels.
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Vitamin E (tocopherols)
- Sources: Vegetable oils (wheat germ, cottonseed, olive, coconut), liver, egg yolk, milk, colostrum,
- Functions: Antioxidant, prevents hemolytic anemia, important for pregnancy in animals
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Vitamin K (phylloquinone/menaquinone)
- Sources: Plants (spinach, cauliflower, cabbage) as phylloquinone; bacteria in the intestines as menaquinone
- Functions: Antihemorrhagic (essential for blood clotting), activates osteocalcin in bone.
Water-Soluble Vitamins
- Information on Water-Soluble Vitamins not included in the provided text.
Vitamin Toxicity
- Vitamin D toxicity (Hypervitaminosis): Usually occurs due to self-medication. Results in hypercalcemia, leading to abnormal calcification in soft tissues (like kidney) and blood vessels, and potentially hypertension
Additional Note
- The provided text included multiple questions. Those questions are not included in the summary as the summary focused on the main topics.
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Description
Explore the essential role of vitamins in human health and growth through this quiz. Learn about their classifications, sources, functions, and the consequences of deficiencies. Discover the distinction between fat-soluble and water-soluble vitamins.
