FNDH 400 Exam 4 Questions and Answers (2022/2023) (Verified Answers)

FNDH 400 Exam 4 Questions and Answers (2022/2023) (Verified Answers) 1-Carbon Metabolism Focused on the metabolism, or movement, of methyl groups Specifically single carbon, primarily -CH3 groups Folic Acid Synthetic Monoglutamate Oxidized form Stable Folate Natural Reduced form Contains multiple glutamates in tail Heat and light sensitive True or False -- Prior to uptake, glutamates will be cleaved off of folic acid to form the monoglutamate form False -- glutamates will be cleaved off of folate not folic acid Functions of folate/folic acid Amino acid metabolism DNA base synthesis Donates a methyl group to cobalamin forming methyl-cobalamin Folate Deficiency -Macrocytic, megaloblastic anemia -Large nucleated red blood cells -Improper red blood cell division True or False -- Spina bifida is the most common neural tube defect that results from failure of the neural tube to close properly. True Which of the following is not a reason why the United States fortifies cereals, grains and some corn masa flour with folic acid? To benefit others (men, elderly etc.) who are not women of child-bearing age -- it is meant to focus specifically on women of childbearing age B12 -Spirulina and fermented soy products are NOT reliable sources -Nutritional yeast and fortified soy milk are good sources of B12 for vegetarians/vegans -Animals consume B12 produced by microorganisms within soil or it is produced by microorganisms in their GI tracts -It is found almost exclusively in animal products Vitamin B12's scientific name Cobalamin-- contains cobalt and many amine groups Do dietary cobalamins equivalents exist? No bc the different cobalamins have similar bioavailibility 2 Cofactor forms of cobalamin -Adenosylcobalamin -Methylcobalamin Most common form of cobalamin found in supplements cyanocobalamin, with some also using methylcobalamin Cyanocobalamin Synthetic form of vitamin B12 Hapatocorrin Salivary glands released by salivary glands before being degraded by proteases in the small intestine. Intrinsic Factor Stomach is produced in the stomach, but binds to B12 in the duodenum. Transcobalamin 2 Enterocyte binds to B12 after intrinsic factor is broken down in the enterocyte after uptake. True or False -- Intrinsic factor is of particular importance to vitamin B12 absorption because uptake into the enterocyte happens through intrinsic factor +B12 binding to cubulin. True Intrinsic factor is extremely important because of its role in vitamin B12 uptake into the enterocyte. Function of Vitamin B12 -Cofactor methionine synthase -Cofactor for enzyme that breaks down odd chain fatty acids -Involved in donating methyl group to homocysteine -Important for maintaining the myelin sheath 2 symptoms of B12 deficiency -Megaloblastic (Macrocytic) Anemia -Neurological abnormalities Megaloblastic (Macrocytic) Anemia -Symptom of B12 deficiency -Same anemia that occurs in folate deficiency -Fewer, enlarged, immature red blood cells -Can occur bc there is not enough cobalamin to convert 5-methyl THF to THF as it normally would -Thus THF is not available for normal DNA synthesis & red blood cells do not divide correctly Most common cause of vitamin B12 deficiency Pernicious anemia Pernicious anemia a condition of inadequate intrinsic factor production that causes poor vitamin B12 absorption common over age of 50 (atrophic gastritis) True or False -- Atrophic gastritis can lead to pernicious anemia, which can then lead to megaloblastic (microcytic anemia) even if vitamin B12 intake is adequate. True Homocysteine Sulfur containing, non-proteinogenic (not used for making proteins) amino acid Elevated circulating homocysteine Found in people with cardiovascular disease D part vitamin part hormone Why is vitamin D considered part hormone? 1) we have the ability to synthesize it 2) it has hormone like functions Synthesized vitamin D we don't synthesize. enough so we need to consume it Vitamin D is a ______ essential micronutrient conditionally Form of vitamin D produced mainly by plants and yeast D2 -- ergocalciferol Form of vitamin D produced mainly by animals D3 -- cholecalciferol Differences between D2 and D3 -D2 contains an extra double bond in its tail -D2 is primarily found in plants True or False -- Starting from cholesterol and going through the intermediate 7-dehydrocholesterol, UV light allows the synthesis of vitamin D2 in the skin which is transported by vitamin D binding protein to the liver. False -- Vitamin D3 is synthesized in humans, not vitamin D2. True or False -- Dietary vitamin D3 is taken to the liver in chylomicrons (taken up as chylomicron remnants), whereas synthesized vitamin D3 is brought there by DBP. True --