Question

1. the function of folic acid is to prevent:

a. neural tube defects
b. visual disturbances
c. pellegra
d. dry, cracked lips

1. vitamin d is sometimes called the sunshine vitamin because:

a. the initial stage of synthesis occurs in the skin when exposed to sunlight
b. the sunlight stimulates synthesis of vitamin d in foods
c. the vitamin is degraded when exposed to sunlight
d. in its natural form the vitamin has a bright yellow appearance

1. a deficiency of vitamin d in growing children will result in the malformation of skeletal tissues called:

a. muscular dystrophy
b. osteoporosis
c. arthritis
d. rickets

1. the fat-soluble vitamin that is responsible for the synthesis of blood-clotting factors by the liver is:

a. a
b. d
c. e
d. k

1. good food sources of the vitamin k would be:

a. leafy, green vegetables
b. cereals and grains
c. vegetable oils
d. fruits

1. the possibility of toxicity is greater with fat-soluble vitamins than with water-soluble vitamins because:

a. foods are a rich source
b. they are included in all vitamin preparations
c. the body can store them
d. they remain in the food during the cooking process

Explanation:

• Question 7: Folic acid (vitamin B9) is crucial for preventing neural tube defects in fetal development. Neural tube defects occur if there is a lack of folic acid during early pregnancy. Visual disturbances are more related to vitamin A issues, pellagra is due to niacin (vitamin B3) deficiency, and dry - cracked lips can be a sign of riboflavin (vitamin B2) deficiency.
• Question 8: Vitamin D is called the sunshine vitamin because the initial stage of its synthesis occurs in the skin when exposed to sunlight. Skin cells contain a form of cholesterol that is converted to vitamin D₃ (cholecalciferol) upon UVB exposure. It is not synthesized in foods by sunlight (option b), it is not degraded by sunlight in a way that would earn it the "sunshine" name (option c), and its natural form does not have a bright yellow appearance (option d).
• Question 9: Rickets is a condition in children caused by vitamin D deficiency. Vitamin D is essential for calcium absorption and bone mineralization. Muscular dystrophy is a genetic disorder affecting muscles, osteoporosis is more common in older adults (though can have multiple causes), and arthritis is an inflammation of joints (not directly due to vitamin D deficiency in children).
• Question 10: Vitamin K is involved in the synthesis of blood - clotting factors (such as prothrombin) by the liver. Vitamin A is important for vision, immune function, etc.; vitamin D for calcium metabolism; and vitamin E is an antioxidant.
• Question 11: Leafy green vegetables (like spinach, kale) are good sources of vitamin K. Cereals and grains are not particularly high in vitamin K, vegetable oils are more of a source for vitamin E, and fruits are generally low in vitamin K.
• Question 12: Fat - soluble vitamins (A, D, E, K) can be stored in the body (in adipose tissue and liver). Water - soluble vitamins (B - complex, C) are not stored to the same extent and are excreted more readily. So, if there is an excess of fat - soluble vitamins, they can accumulate and cause toxicity. Just because foods are a rich source (option a) or they are in vitamin preparations (option b) or they remain in food during cooking (option d) does not explain the higher toxicity risk compared to water - soluble vitamins.

Answer:

1. A. neural tube defects
2. A. the initial stage of synthesis occurs in the skin when exposed to sunlight
3. D. rickets
4. D. K
5. A. leafy, green vegetables
6. C. the body can store them