Exam 3 Review (Final)-1

Exam 3 Review (Final)-1 - NST 10 Introduction to Human...

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NST-10 – Introduction to Human Nutrition University of California, Berkeley Fall 2010 Exam III Review Fat Soluble Vitamins (10/25/10) 1. Which vitamins are fat-soluble and how are they absorbed differently from water-soluble vitamins? Fat soluble vitamins require bile acids, digestive enzymes. The small intestine absorbs fat-soluble vitamins similarly. 2. True or False : The gut bacteria produce enough vitamin K that most people do not need to consume extra in their diet. 3. Vitamin A is the compound retionol , which can undergo metabolism to become a retinoid. a. List the two classes of Retinoids and their functions: Retinoic Acid: development, growth, reproduction, epithelia, immune system, nervous system Retinal: Visual cycle b. Which one does the body produce more of? Retinoic acid c. Which one is arguable more important? Why? Retinoic acid is not more important because it is teratogenic. Also, retinoids can treat better cystic acne. 4. Fill in the blanks for the mechanism of Retinoic Acid: Vitamin A is obtained through the diet by eating carrots, tomatoes, etc which contain carotenoids , or provitamin A. After digestion, retinol is absorbed through the walls of the small intestine and taken to the liver where it is converted to retinoic acid or stored. The RA activates a gene that was previously suppressed and this creates new proteins resulting in a change in cell function. 5. What is the RDA for Vitamin A and what can overdose lead to? 0.3mg to 1.3mg.
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Fat-Soluble Vitamins (Part II) (11/01/10): 1. What is the only hormone that can induce the intestine to absorb dietary Calcium? Calcitriol a. What is its precursor and where is it produced? Vitamin D3 Skin 2. The endocrine system works to maintain levels of calcium in the blood , which is important for blood clotting. The excess calcium is deposited in bone and acts as a reservoir for times when dietary calcium is low . Calcium also functions to support the structure of bone. When blood calcium levels drop, it is sensed by the , which begins to secrete . This signals enzymes in the kidney to convert Vitamin D3 into calcitriol . This hormone instructs the small intestine to absorb calcium. It also causes bone to release calcium into blood. If you have enough circulating calcium, the excess will be in the bone. 3. True or False : Because bone provides the structure for the body, it is not metabolically active. 4. The RDA for Vitamin D is anywhere from 5 to 15 micrograms and most people [ do/ do not ] get enough of this vitamin from sunlight exposure. a. Is the RDA for Vitamin D adequate? Probably not 5. What is Rickets and what is the cause? Lack of Ca++/vitamin D, failure to convert Vitamin D into calcitriol, or failure of calcitriol to regulate gene expression causes Rickets, where the bones are not calcified. 6. What are risk factors for osteoporosis?
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Exam 3 Review (Final)-1 - NST 10 Introduction to Human...

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