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46 Cards in this Set
- Front
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List water soluble vitamins: In general, how are they stored/absorbed in the body? |
Vit B1,2,3,6,12
Vit C Folate Panthotenic acid Biotin Absorption: through intestines Storage: only B12 & B6 can be stored, rest cannot |
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List lipid soluble vitamins: In general, how are they stored/absorbed in the body? |
Vit A
Vit D Vit E Vit K Absorption: absorption through lipids, packaged in chylomicrons Storage: in liver or adipose tissue |
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Main function, coenzymes, etc Vitamin A (retinol, retinal, retinoic acid) |
function:
Vision- retinal part of rhodopsin in rod & cone cells Cell signaling- retinoic acid binds to intranuclear receptors & modulates genes expression - maintanence of epithelium (infection protection), spermatogenesis, embryonic dvlpmnt * dark-green, leafy veg, animal liver products |
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Vitamin A (retinol) toxicity
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*due to excess vitamin supplements
-dry skin, mouth sores, loss of appetite, vomiting, hepatomegaly, liver failure -teratogen (avoid excessive amounts if pregnancy is planned) |
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Vitamin A (retinol) deficiency
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-impaired vision
mild: night blindness severe: complete blindness due to keratinization of epithelial cells -increased frequency of infections decreased integrity of epithelium, leading to more pathogen invasions |
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Role of Vitamin A in vision cycle |
-beta-carotene is used to produce all-trans-retinal
-all-trans-retinal is converted to 11-cis-retinal -11-cis-retinal is combined w/ opsin producing rhodopsin -->light photon acts on rhodopsin & signal is passed through optic nerve (rhodopsin converted back to all-trans-retinal) |
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Main function, coenzymes, etc Vitamin D |
Function:
-increases calcium absorption from intestine -decreases renal calcium excretion -mobilizes calcium from bones = maintains plasma calcium levels |
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Describe Vitamin D homeostasis
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-Dietary Vitamin D3, taken into chylomicrons & absorbed into lymph, provitamin D3 in skin is converted to Vitamin D3 upon UV exposure, both sources of Vitamin D are stored in liver
-Hydroxylated 25(OH)2D3 enters circulation and may come into contact with PTH in the kidney -PTH causes further hydroxylation to 1,25(OH)2D3, this form increases bone Ca2+ release--> increasing plasma Ca2+ -PTH is secreted in response to low plasma Ca |
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Vitamin D deficiency
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soft, pliable bones (bow leg)
children: rickets adults: osteomalacia |
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Vitamin D toxicity
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-loss of appetite, nausea, thirst, stupor
-hypercalcinemia (calcium deposits in kidney & arteries |
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Main function, coenzymes, etc Vitamin E (tocopherols) |
Function:
*main fat-soluble antioxidant of human body -protects membrane-lipids from free radical damage |
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Vitamin E (tocopherol) deficiency
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-hemolytic anemia in premature infants (tocopherol stores not yet formed)
-nerve damage in older children & adults (myelin damaged) |
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Main function, coenzymes, etc Vitamin K |
Function: blood coagulation
Coenzyme for: synthesis of y-carboxylglutamate (essential for Ca2+ binding to proteins) Precursor for: glutamate carboxylation *inhibited by Warfarin (anti-coagulant, antagonist of vit K) *from intestinal bacteria, green leafy veg |
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Vitamin K deficiency
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bleeding in newborns (intestinal bacterial flora has not yet formed)
-newborns receive Vit. K injection at birth Bleeding may occur in adults if bacterial flora is killed by antibiotics |
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Main function, coenzymes, etc Vitamin B1 (thiamine) |
*thiamine-pyrophosphate (active form_
Coenzyme for: -pyruvate dehydrogenase (acetyl-CoA production) -alpha-ketoglutarate dehydrogenase (TCA) -alpha-ketoacid dehydrogenase (branched AA degradation) (^oxidative decarboxylations) -transketolase (pentose phosphate pathway) |
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Vitamin B1 (thiamine) deficiency
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neurological symptoms (bc pyruvate dehydrogenase and a-ketoglutarate dehydrogenase are important for energy source for brain)
*def assayed through RBC transketolase activity Berberi: -infantile form: tachycardia, vomiting, convulsion -adult form: dry skin, irritability, disorderly thinking, progressive paralysis Wernicke-Korsakoff syndrome (chronic alcoholism): -alcohol impairs thiamine absorption from intestines -apathy, loss of memory, confusion, inability to move eyes Deficiency can be assayed via RBC transketolase activity |
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Differentiate between the following Vitamin B1/Thiamine deficiencies:
Berberi Wernicke-Kosakoff Syndrome |
Berberi:
-severe thiamine deficiency -infantile, tachycardia, vomiting, convulsion -adult, dry skin, irritability, disorderly thinking, progressive paralysis Wernicke-Kosakoff Syndrome: -chronic alcoholism impairs intestinal thiamine absorption -apathy, loss of memory, confusion, inability to move eyes |
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Main function, coenzymes, etc Vitamin B2 (Riboflavin) |
-coenzyme in FMN & FAD form, used in ox-red
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Vitamin B2 deficiency
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rare!
cheliosis (cracked lips at corners), dermatitis, glossitis (purple smooth tongue) *Pharm- used to lower cholesterol, reduces lipolysis in adipose, reduces TG, VLDL, LDL |
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Main function, coenzymes, etc Vitamin B3 (niacin) |
-precursor for NAD & NADP
*can be subsituted by tryptophan *used as a drug for high cholesterol, reduces lipolysis in adipose & TG, VLDL, LDL, in blood |
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Vitamin B3 deficiency
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pellagra (Four D's: dermatitis, diarrhea, dementia, death)
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Vitamin B3 toxicity
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skin flushing, itching, tingling, burning sensation on skin
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Main function, coenzymes, etc Vitamin B6 (pyridoxine) |
*pyridoxal phosphate (active form)
-coenzyme for: heme synthesis, transamination, deamination, decarboxylation (dopamine, histamine, serotonin, GABA synthesis) *Isoniazid, anti-tuberculosis drug depletes pyridoxal-phosphate |
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Vitamin B6 deficiency
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rare!
hyperirritability, neuritis, convulsions |
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Vitamin B6 toxicity
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rare! from excess supplements
nerve damage |
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Main function, coenzymes, etc Vitamin C (ascorbic acid) |
-collagen synthesis
-neurotransmitter synthesis (DOP-->NORE) -tyrosine degradation -antioxidant |
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Vitamin C deficiency
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bleeding, bruising, delayed wound healing, loose teeth
extreme: scurvy |
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Vitamin C toxicity
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intestinal problems, diarrhea
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Main function, coenzymes, etc Panthotenic Acid |
-precursor for CoA
(palmitoyl-CoA, acetyl-CoA, acetoacetyl-CoA, succinyl-CoA) *def rare, no toxicity |
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Main function, coenzymes, etc Biotin |
-coenzyme in carboxylation reactions
*bioavailability, corn & soy, some in wheat |
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Vitamin B8 (Biotin) deficiency
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rare!
(avidin in egg white binds strongly, making unavailable *no toxicity |
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Differentiate btwn the roles holocarboxylase synthase & biotinidase
What enzyme deficiency causes multiple carboxylase deficiency? |
holocarboxylase synthase-
botin + enxyme ---> enzyme-biotin (covalent link) biotinidase- enzyme-biotin---> biotin + enzyme Deficiency in EITHER causes multiple carboxylase deficiency |
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Main function of the following trace element:
Iron |
-part of heme (chelated to prophyrin ring) & non heme proteins (iron-sulfur clusters)
(60-80% in hemoglobin) -toxic if not bound to proteins |
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Explain the role of the following enzymes in iron metabolism:
Hepcidin Ferritin Ceruloplasmin Transferrin |
Hepcidin- regulates absorption in liver
Ferritin- iron storage in liver (as Fe3+) Ceruloplasmin- controls oxidation (converts Fe2+ to Fe3+ allowing storage) Transferrin- transports Fe3+ (albumin transports Fe2+) |
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Iron deficiency
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Anemia
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Iron toxicity
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hemochromatosis (iron overload), liver and pancreatic damage, heart problems, arthritis, impotence
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Main function of the following trace element:
Copper |
-necessary for the stability of ceruloplasmin
*transported in circulation 90% by ceruplasmin (10% albumin) |
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Differentiate btwn the following copper transporters
CRT1 ATOX1 ATP7A ATP7B |
CRT1- membrane transporter
ATOX1- intracellular transporter (chaperon) ATP7A- intestinal pump, ATP dependent ATP7B- liver pump, ATP dependent |
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Diseases of copper metabolism
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Menkes Disease (deficient ATP7A):
Deficient Cu INTESTINAL UPTAKE neurological effects, growth retardation, hypopigmentation, laxity of skin TX- copper-histadine Wilson's Disease (deficient ATP7B): Deficient Cu EXCRETION; cirrhosis, liver failure, neurological defects, psychiatric symptoms TX- copper restricted diet, chelators, oral zinc *both lead to low blood ceruloplasmin |
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Main function of the following trace element:
Zinc |
-essential for many enzyme/protein functions
-wound healing, skin integrity, spermatogenesis, pancreatic function *stored in metallothioneine (high levels induce production of metallothioneine) |
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Zinc deficiency
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Acrodermatitis enteropathica (deficient zinc transporter):
red and inflamed patches of dry, scaly skin that becomes blistered lesions; hair loss; diarrhea |
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Main function of the following trace element:
Iodine |
thyroid hormone synthesis
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Iodine deficiency
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Goiter (lack of iodine in diet --> enlarged thyroid gland)
Cretinism (mother lacked iodine intake during pregnancy --> mental and growth retardation) |
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Main function of the following trace element:
Selenium |
-present in selenocysteine & selenomethionine
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Selenium toxicity
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brittle nails and hair, intestinal problems, garlic-like body odor, neurological problems
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Selenium deficiency
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Keshan disease (China): cardiomyopathy
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