40 Questions
What are vitamins classified into two categories based on their solubility?
Fat-soluble and water-soluble
What is the primary function of water-soluble vitamins?
To act as coenzymes for enzymes in intermediary metabolism
Which vitamin is essential for the biosynthesis of several compounds?
Folic acid
What happens when vitamins A and D are consumed in excess of the Dietary Reference Intakes (DRIs)?
They can lead to accumulation of toxic quantities of these compounds
What is the result of a lower than normal concentration of hemoglobin in the blood?
Anemia
What is the primary function of tetrahydrofolate?
To receive one-carbon fragments from donors
Which population is particularly susceptible to folic acid deficiency?
Pregnant women and alcoholics
What is the compound synthesized in the presence of folic acid?
Thymidine mono phosphate (TMP)
Which of the following is a primary source of pantothenic acid?
Yeast
What is the main function of retinoic acid in the body?
Mediating most of the actions of retinoids
What is the term for the family of molecules related to retinol (vitamin A)?
Retinoids
What is the result of the oxidation of retinol?
Retinal
What is the function of retinal in the body?
Vision
What is the result of the oxidative cleavage of β-carotene in the intestine?
Two molecules of retinal
What is the role of the intestinal mucosa in the absorption of vitamin A?
Hydrolyzing retinyl esters
What is the form in which vitamin A is transported from the intestine to the liver?
Retinyl esters
What is the role of 11-cis retinal in the visual cycle?
It combines with opsin to form rhodopsin
Which symptom is an early sign of vitamin A deficiency?
Night blindness
Which vitamin A form is inactive in maintaining reproduction and the visual cycle?
Retinoic acid
What is the recommended dietary allowance (RDA) of vitamin A for adult females?
700 RAE
Why are animals given vitamin A only as retinoic acid from birth blind and sterile?
Retinoic acid is inactive in maintaining reproduction and visual cycle
What role do yellow and dark green vegetables play in vitamin A nutrition?
They are precursors of vitamin A
What is the role of vitamin A in the maintenance of epithelial cells?
Promoting mucus secretion
How is vitamin A used in clinical treatments?
Retinol and retinyl esters treat vitamin A deficiency
What are FMN and FAD bound to in flavoenzymes?
tightly or covalently
What are common symptoms of riboflavin deficiency?
cheilosis and glossitis
What role does biotin play in carboxylation reactions?
Carrying activated carbon dioxide
What glycoprotein in raw egg whites prevents the absorption of biotin?
avidin
Why does biotin deficiency not naturally occur?
It is synthesized by intestinal bacteria
What component of coenzyme A (CoA) carries acyl compounds?
A thiol group
What is required to induce a biotin deficiency syndrome with a normal diet?
20 eggs/day
What deficiency frequently accompanies riboflavin deficiency?
Other vitamin deficiencies
Why is it recommended that all newborns receive a single intramuscular dose of vitamin K?
As prophylaxis against hemorrhagic disease
What can prolonged administration of large doses of synthetic vitamin K (menadione) cause in infants?
Hemolytic anemia and jaundice
Which of the tocopherols is the most active form of vitamin E?
Alpha-tocopherol
What is the primary function of vitamin E?
Acting as an antioxidant
Which foods are rich in vitamin E?
Vegetable oils
What is the recommended dietary allowance (RDA) for alpha-tocopherol in adults?
15 mg
Who is most likely to experience vitamin E deficiency?
Premature infants
Why is vitamin E not recommended for the prevention of chronic diseases like coronary heart disease or cancer?
Clinical trials have been disappointing
This quiz covers the basics of vitamins, including their classification, functions, and importance in human health. Learn about the different types of vitamins and their roles in the body.
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