Metabolism Exam Three 1 What form of vitamin D is the major circulating form with a half life of 2 For what enzyme or protein is vitamin K a necessary cofactor approximately three weeks 25 OH 2D3 Gamma glytamyl carboxylase 3 Bile is synthesized in the Liver food supply Alpha tocopherol 4 What tocopherol form provides the most vitamin E activity in the US 5 One of the targets of PTH is the kidney specifically the distal convolutes tubule What process does PTH stimulate in the distal convoluted tubule and how does this affect plasma calcium levels Increase renal absorption increase plasma calcium 6 What carotenoid has the greatest vitamin A activity 7 Which of the following is needed for the visual cycle 8 What is the primary catabolic enzyme promoting the inactivation of the Beta carotene 11 cis retinal 1 25 OH 2D3 24 alpha hydroxylase Cholecalciferol 9 Which vitamin below is believed to function like a steroid hormone 10 PTH positively regulates the expression of which enzyme in the kidney that is involved in synthesized 1 25 OH 2D3 1 alpha hydroxylase 11 Carotenoids as thought to protect against the development of cardiovascular disease by preventing the oxidation of LDL 12 Which compound is most associated with less oxidized LDL and decreased risk of development of foam cells or atherosclerotic lesion Alpha tocopherol 13 Which fat soluble vitamin appears to operate as a coenzyme or cofactor that modifies proteins to enhance calcium binding Menaquinone 14 Within the cell nucleus all trans retinoic acid and or 9 cis retinoic acid binds to Nuclear hormone receptors RAR or RXR 15 For which vitamin is the tolerable upper intake level set because of an increased risk of bleeding Vitamin E 16 Retinoic acid supports all of the following biochemical cellular or physiological processes except Vision and reproduction 17 Immediately following a balanced meal that contained tocopherol where would you most likely find the majority of the dietary tocopherol in the body In chylomicrons in the lymphatics and or general circulation 18 Which of the following nutrients plays a direct role in modulating the function and or activity of the transcription factors Trans retinoic acid 19 A common cause of vitamin K deficiency in adults is related to Prolonged use of antibiotics 20 Induction of a protein ie increasing the amount of a protein via enhanced gene expression can be accomplished by More than one of the above A E K D 21 Loss of due to a genetic deficiency can contribute to the formation of a vitamin E deficiency syndrome Alpha tocopherol transfer protein 22 What is the most well accepted and best known function of vitamin K Coagulation 23 Which of the following endogenously synthesized molecules is converted to previtamin D3 in the skin in the presence of UV radiation 7 dehydrocholesterol 24 Which of the following symptoms might be attributed to alterations in intestinal absorption in a patient with Celiac Disease Increased clotting time elevated levels of PTH decreased half life of erythrocytes night blindness 25 The main characteristic of rickets is Osteomalacia or poorly mineralized bones 26 Which of the following food is relatively rich source of tocopherol 27 What is the principle transport vehicle for vitamin E in the blood 28 is the form of vitamin K that is the byproduct of gamma glutamyl Wheat germ HDL LDL VDL carboxylase 2 3 epoxide 29 Which of the following carotenoids has little to no vitamin A Xanthophyll lycopene zeaxanthin alpha carotene 30 Warfarin and similar anticoagulants function to decrease clotting by inhibiting the enzyme Epoxide reductase 31 One of the many functions of PTH is to Promote calcium reabsorption in the kidney 32 Bone forming cells are know as the whereas the bone resorbing cells are known as Osteoblast osteoclast 33 Glucagon secreted by the cells of the endocrine pancreas is responsible for stimulating and Alpha glycogenolysis gluconeogenesis 34 Because osteoclastin is a target of VDR and required post translational modification to promote mineralization both and are essential for optimal bone health 1 25 OH 2D3 phylloquinone 35 In order to be transported as a component of a chylomicron retinol in the enterocyte is Esterified by lecithin retinol acyl transferase 36 When plasma calcium levels are low the synthesis of the hormone is stimulated in the kidney 1 25 OH 2D3 37 The active form of vitamin A that contributes to the regulation of cellular differentiation and or proliferation is Retinoic acid 38 Once in the enterocyte dietary is cleaved by 15 15 monooxygenase to produce Beta carotene retinal 2 39 As plasma levels of rise the cytochrome P450 enzyme with 25 hydroxylase activity is induced to help maintain vitamin D homeostasis 1 25 OH 2D3 40 In patients with advanced renal disease a decreased capacity to excrete phosphorus in addition to a decreased production of to synthesize active vitamin D may both contribute to a condition known as secondary hyperparathyroidism 1 alpha hydroxylase 41 Briefly describe the mechanism through which an inadequate vitamin status may contribute to an increased risk of fracture and development of osteoporosis Decreased vitamin K intake results in less carboxylation and lower calcium binding Calcium is necessary in bone matrix formation so without it the bone will become compromised resulting in increased risk of osteomalacia and osteoporosis 42 Explain the etiology of hemolytic anemia as a result of a deficiency of one of the fat soluble vitamins and identify this vitamin Hemolytic anemia is largely due to low vitamin E concentration in red blood cells RBC carry oxygen and have very unsaturated membranes which can put them at risk for oxidation If vitamin E levels are low oxidation and therefore destruction of RBC will occur 43 Name the two transport proteins that are required for retinol transport independent of lipoproteins from the liver to other extrahepatic tissues of the body RBP TTR 44 In a population of lactose intolerant individuals with limited income describe two dietary recommendations you would advise to decrease the risk of developing a sub clinical vitamin A deficiency Provide ratinonale to support your answer Carrots high in beta carotene lactose free relatively inexpensive Tuna high in vitamin A lactose free relatively inexpensive 45 The cells in the liver store the majority of vitamin A found in the hepatic tissue Stellate Bonus 1 What is the last name of the scientist employed at the University of