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Globin protects the heme (no globin Fe2 is oxidized to Fe3 and no oxygen binding) and provides another co-ordination site for FeHighly bioavailable; in the duodenum the metal porphyrin ring is split off from the globin; evidence that there is a heme-iron receptor/transporter in the enterocyte; once inside enterocyte, the heme may be split into the ferrous iron (Fe2), the released ferrous iron is then likely to enter into the low molecular weight pool of iron in the enterocte and exit enterocyte via a common pathway along with iron absorbed as nonheme ironpresent in diet as Fe2 or Fe3; rapidly oxidized in stomach to Fe3; ascorbate most important luminal accessory for iron, aids in the intestinal absorption of iron by reducing ferric iron to ferrous iron (Fe2), in stomach low pH is important for relasing iron from ligands in food, as is the action of various digestive enzymes, which destroy high molecular weight ligands and create new ones, Ca intake may inhibit iron absorptioninsoluble iron storage compound produced by the body when iron exceeds the storage capacity of ferritinessential for the delivery of oxygen to cells; hemoglobin and myoglobin are oxygen-containing proteins that contain iron; most of iron in the body is part of hemoglobincontrolled primarily at intestine; in enterocytes (3-7 day lifespan) iron can be bound to ferritin for storage; leave enterocyte and enter the bloodstream, iron must b converted from 2 to 3; iron is then transported out of the enterocyte and is bound to transferrin for transport to tissues; transferrin-iron complex must bind transferrin receptors to be taken up by cellsexpression of the gene for transferrin receptors is increased, resulting in increased transferrin receptors and expression of gene for ferritin is reducedexpression of the gene for transferrin receptors is reduced, resulting in less iron getting into cells; gene for ferritin is increased; resulting in increased iron stored in enterocyteiron deficiency anemia-hemoglobin cannot be produced which means red blood cells are microcyctic and hypochromic and unable to deliver sufficient oxygen to tissues; at risk groups- infants, children, adolescents, women of reproductive age, pregnant womencan damage intestinal lining and cause abnormalities in body pH, shock and liver failureinherited condition that allows increased iron absorption; accumulates in tissues over time and can lead to heart, liver, pancreas damageessential for growth and development; better absorbed from animal sources because zinc can be bound by plant phylates; most abundant intracellular trace element; involved in function of over 300 enzymes, including superoxide dismutase, important for protecting cells from free radical damagetransport proteins regulate amount of zinc in mucosal cells; promote transport of zinc from intestinal lumen into cell or reduce zinc by transporting zinc back into the lumen or into storage vesicles; amount of zinc can be regulated by increasing or decreasing synthesis of proteins that transport Zn in vs. those that transport Zn out of mucosal cellsmetal binding protein that regulates the amount of Zn that passes from the mucosal cell into blood; increased synthesis of this protein occurs when zinc levels are highinvolved in function of superoxide dismutase, used in enzymes that function in the synthesis of DNA and RNA, used in enzymes involved in carb metabolism and in acid-base balance; plays a role in storage and release of insulin, mobilization of vitamin A from liver and stabilization of cell membranes; influences hormonal regulation of cell division; important for immune system functionwhen there is a defect in zinc absorption and metabolism develop this zinc-deficiency diseaseppl with diets low in protein and high in phylates; individuals with kidney disease, alcoholism, and cancerpoor growth and development, skin rashes, hair loss, diarrhea, neurological changes, reduced reproduction, reduced immune function, skeletal abnormalitiesGi irritation, vomiting, loss of appetite, diarrhea, abdominal cramps, headaches; has occurred with consumption of foods and beverages contaminated with zinc that has leached from galvanized containers; main problem with Zn toxicity is Cu deficiency; metallothionien binds Cu as well as Znexists in +1 and +2 states, majority is 2, Zinc can decrease bioavailabilityCytochrome c oxidase (CCO;Cu containing enzyme) is a key component of the electron transport chain located in the inner mitochondrial membraneabout 30-40%; transported to liver bound to albumin; liver produces ceruloplasmin (binds copper and transports it to other tissues); copper is removed by excretion in bile and subsequent elimination in the fecesinfants with chronic diarrhea, pantients undergoing chronic peritoneal or renal dialysis, severe burn patients or individuals with inherited mutations of genes regulating Cu homeostasis; Menkes diseaserare genetic disorder that results in a copper deficiency due to a defect in intestinal copper absorptionAnemia that results from defective iron mobilization (only corrected by Cu supplementation); abnormalities of bone development related to Cu deficiency ; Hypertriglyceridemi and hypercholesterolemiarare genetic disorder, Wilson's disease, results in Cu overload due to inability to excrete Cu in bileconstituent of some enzymes and activator or other enzymes; manganese-requiring enzymes are involved in amino acid, carb and cholesterol metabolism, cartilage formation, urea synthesis and antioxidant protection needed for activity of a form of superoxide dismutasecontent in food depends on soil they are grown in; is the 21st amino acid (can replace sulfer in sulfur containing amino acids); essential component of 25 cysteine containing proteinsmuscular discomfort and weakness and Keshan diseaseSe deficiency and viral infection causes heart diseasenausea, diarrhea, fingernail and hair changes, fatigue and irritability; can cause death from overloadessential component of 25 Se-cysteine containing proteins:content in food depends on soil; near ocean or sea is higher; most in diet comes from iodized salt; more than half in body is found in thyroid gland; essential component of thyroid hormones including thyroxineabsorbed rapidly and completely from GI tract in form of iodide ions; essential component of thyroxine (T3) and triiodothyronin (T3) which are made from the amino acid throsine; T4 predominant in blood and converted to active form T3 by the selenoprotein iodothyronine deiodinasework by affecting gene expression in target cells; promote protein synthesis, and regulate basal metabolic rate, growth, and developmentin response to cold or stress hypothalamus releases TRH which stimulates pituitary to release TSH (also released when thyroid hormone levels are low) TSH stimulates thyroid gland to take up iodine and synthesize thyroid hormone; iodine adequate hormones made and presence turns off synthesis of thyroid stimulating hormonemultiple adverse effects on growth and development; Goiter-thyroid enlargement; as iodine intake decreases, secretion of TSH increase-TSH stimulate thyroid hypertrophy and hyperplasia;Acute iodine poisoning: GI irritation, abdominal pain, nausea, vomiting, diarrhea, cardiovascular symptoms, coma, cyanosis ( most people remarkably tolerant) large excess leads to goitermajor functions related to effects on mineralization of bone and teeth; present in small amount in all soil, water, plants and animals; flouridated water, tea, toothpast; water flouridation recommented by ADAflourosis- changes in bone, kidney, and possibly nerve and muscle damage;

Sketch a model of an atom of helium, showing the electrons, protons, neutrons, and atomic nucleus. .312 In the face of the image, zinc favors the growth and strengthening of the hair. the nucleus decays spontaneously giving off particles and energy. Vitamin B12 has a core consisting essentially of cobalt.

compound in which electrons in its covalent bonds are not shared equally.