FNDH 620 - Final Exam 2022 (COMPLETE SOLUTIONS)

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FNDH 620 - Final Exam 2022 (COMPLETE SOLUTIONS) True or False Vitamins: - cannot be made in the body - noncaloric - required in small amounts (mg and mcg) - ✔✔TRUE Vitamins: - cannot be ma... de in the body - noncaloric - required in small amounts (mg and mcg) What 3 forms can vitamin A take? - ✔✔- retinol (alcohol) - retinal (aldehyde) - retinoic acid (acid form from retinal) What form of vitamin A is normally found in blood and tissues? - ✔✔Retinyl Palmitate What form of vitamin A is found in plants? - ✔✔Previtamin A - carotenoid structure that includes the carotenes and xanthophylls - found in plants - needs to be converted to active vitamin A What is the most potent form of vitamin A? - ✔✔Beta carotene Where can retinyl esters be found? - ✔✔Animal Products *only* Where can vitamin A be found? - ✔✔Fortified milk and milk products Where can previtamin A carotenoids be found? - ✔✔Plant sources - orange and dark green vegetables Vitamin A containing micelles form and traverse the enterocyte plasma membrane by what type of diffusion? - ✔✔Passive Diffusion What two things are needed in the digestion of vitamin A? - ✔✔Bile and Fat Beta-carotene and other carotenoids can be converted to retinol by what means? - ✔✔Beta-carotene and other carotenoids can be converted to retinol by cleavage of the central double bond When beta-carotene is cleaved, how many molecules of retinal does it make? - ✔✔1 beta-carotene = 2 retinal Retinyl, retinyl esters, and carotenoids are packaged into what and transported where? - ✔✔Retinyl, retinyl esters, and carotenoids are packaged in *chylomicrons* and transported in the *lymphatic system*. Vitamin A and carotenoids are metabolized where and as what? - ✔✔Vitamin A and carotenoids are metabolized in the liver as chylomicron remnants. Retinoic acid is absorbed and transported to which organ bound to what protein? - ✔✔Retinoic acid is absorbed and transported to the liver bound to albumin. The liver stores 90% of which vitamin? - ✔✔vitamin A What are the functions of vitamin A & Carotenoids? - ✔✔- Improves vision - Cell differentiation & cell proliferative activity - Fights cancer - Development of embryo tissue - Synthesis of glycoproteins - Reproductive processes - Antioxidant capacity - Bone development and maintenance - Provides immunity How is vitamin A essential to our vision? - ✔✔- retinol is transformed into 11-cis retinal through a series of reactions - 11-cis retinal combines with the protein opsin forming rhodopsin - Rhodopsin + light changes the conformation of the protein which begins a cascade of events leading to the generation of an action potential - This action potential sends neural impulses to the optic center of the brain translating it into images What are the 2 nuclear receptors that work with vitamin A on a molecular level? - ✔✔RAR & RXR Vitamin A is beneficial for all cancers but... - ✔✔lung cancer Vitamin A is involved in sperm development and differentiation, without it, what happens? - ✔✔Without RARγ, males are sterile If a female is low or deficient in vitamin A, what could happen? - ✔✔deficiency: inability of implantation of the egg low: may allow implantation but may end in a miscarriage; various birth defects Vitamin A is excreted in _____ & _____. - ✔✔Vitamin A is excreted in the bile (70%) and urine (30%). RDA of vitamin A for men - ✔✔900 mcg/day RDA of vitamin A for women - ✔✔700 mcg/day 12 mcg beta-carotene = ??? mcg of retinol - ✔✔12 mcg beta-carotene = 1 mcg of retinol Vitamin A deficiency is the leading cause of ___________ in children worldwide. - ✔✔Vitamin A deficiency is the leading cause of *non-accidental blindness* in children worldwide. Diseases caused by vitamin A deficiency - ✔✔- night blindness - xerophthalmia - bitot spots Symptoms of vitamin A toxicity - ✔✔- decreased appetite - dry, itchy, flaky skin - headache - hair loss - bone/muscle pain - ataxia - nausea/vomiting - dry mouth - eye irritations - conjunctivitis - birth defects - miscarriage - learning difficulities This unique vitamin is synthesized in the body with adequate sun exposure as well as it's ability to function as a hormone. - ✔✔Vitamin D What are the two forms of vitamin D? - ✔✔D2 - ergocalciferol D3 - cholecalciferol UV light converts __________ into cholecalciferol (D2). - ✔✔UV light converts *7-dehydrocholesterol* into cholecalciferol (D2). Aside from humans being able to produce their own amounts of vitamin D, it can also be found in: - ✔✔- animal foods (eggs, liver, fatty fish, & butter) - fortified milk and dairy products - fortified margarine Vitamin D enters mucosal enterocytes by __________ diffusion. - ✔✔Vitamin D enters mucosal enterocytes by *passive* diffusion. Vitamin D becomes part of __________ and then enters the __________ circulation. - ✔✔Vitamin D becomes part of *chylomicrons* and then enters the *lymph* circulation. 40% of vitamin D is transported in chylomicrons. The remaining 60% is transported by what protein? - ✔✔D-binding Protein (DBP) - this is also the same protein that picks up vitamin D created in the skin The efficiency of binding to vitamin D is increased after two ____________. - ✔✔The efficiency of binding to vitamin D is increased after two *hydroxylations*. Both the _____ and the _____ add a hydroxyl group to the vitamin D structure. - ✔✔Both the *liver* and the *kidneys* add a hydroxyl group to the vitamin D structure. When vitamin D levels are low, what becomes more efficient? - ✔✔25-hydroxylase When light hits the skin, what is the pat [Show More]

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