Term
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Definition
| non protein component of an enzyme |
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Term
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Definition
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Term
| why aren't vitamins made by organisms? |
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Definition
requires energy for synthesis
control of synthesis is metabolically expensive
cheaper to get nutrients from diet |
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Term
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Definition
vitamin D, vitamin E, Vitamin A, vitamin K
absorption dependent on fat absorption pathway; fat malabsorption may cause deficience |
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Term
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Definition
thiamin, riboflavin, niacin, B-6, B-12 (cobalamin) biotin, pantothenic, folate, C (ascorbic acid), choline
dissolve in watery components of foods and the body, excreted in urine, most are not stored, generally nontoxic, have unique membrane transport proteins |
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Term
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Definition
fat soluble antioxidant, protects membrane unsaturated FA's
alpha-tocopherol (in liver transported by high affinity binding alpha-TTP)
deficiency results in HEMOLYTIC ANEMIA AND PERIPHERAL NEUROPATHY |
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Term
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Definition
most active form is Retinol and is a constituent of Retinal visual pigment
one of the few caretenoids (beta carotene) that the body can convert to retinol
in excess (polar bear liver consumption) can be lethally toxic
deficiency can lead to night blindness (quickly use retinol and can't refocus in dim lighting) and dry skin (xeroderma) |
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Term
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Definition
sunshine vitamin
intestinal Ca2+ absorption and regulation through dietary fat pathway
7-dehydrocholesterol-->D3-->25 hydroxycholecalciferol(calcidiol)--> 1,25-dihydroxycholecalciferol (active calcitriol
requires sunlight, liver and kidney processing
calcium can be absorbed paracellularly or transcellularly with vitamin D synthesis of Calcium channels, pump and exchange; also induces formation of carrier--> calbindin in duodenum
Vitamin D deficiency=rickets in children and osteomalacia in adults (soft and deformed bones) (maybe caused by diarrhea and vomiting)
tetany: involuntary muscle contraction
in excess = hypercalcemia, hypercalciuria, loss of appetite and stupor
Liver disease or kidney disease may impair the conversion to calcitriol |
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Term
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Definition
cofactor of carboxylation of glutamic acid residues, synthesis of prothrombin and other blood coagulation factors
absorbed in jejunum and ileum from plants, animals and intestinal bacteria (large intestine)
deficiency= hemorrhagic disease (rat poison) and bleeding gums
warfarin is a vitamin K antagonist (coronary artery disease) |
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Term
| disorders causing fat soluble vitamin deficiency |
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Definition
cystic fibrosis: decreased pancreatic enzymes
celiac sprue: decreased absorptive surface area
laxative abuse
steatorrhea: excess fat in feces
chronic liver disease
disorders of fat metabolism
disorders of bile secretion |
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Term
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Definition
| often work together and are present together in many of the same foods |
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Term
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Definition
thiamin is a cofactor in glycolysis, TCA cycle, HMP shunt, and BCAAD
in low concentrations it is actively transported, in high concentrations it is passively transported (jejunum and ileum)
deficiency = beriberi (polyneuritis and muscle wasting)
wernicke-korsakoff syndrome: degenerative brain disorder frequent in alcoholics
korsakoff's: amnesia and memory problems |
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Term
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Definition
used in redox reactions (NAD, NADP)
from tryptophan and requires B6 for synthesis
deficiency: pellagra (4D's dermatitis, diarrhea, dementia, death) Hartnup's Disease: inability to absorb dietary tryptophan results in niacin deficiency |
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Term
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Definition
used to synthesize DNA, purines, and thymine
PteGlu1 is absorbed by an apical folate-OH exchanger (small intestinal brush border peptidase)
deficiency =megaloblastic anemia (RBC's don't split apart)
neural tube defects: high AFP, spinal bones fail to enclose the spinal cord and spina bifida |
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Definition
| deficiency: rare and may come from avidin which binds biotin and prevents absorption; dermatitis, alopecia, enteritis |
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Term
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Definition
absorption is a multistep process: salivary glands secrete R-binder protein; low gastric pH liberates protein-bound B12 and it is bound to R binder protein in stomach; IF is released from gastric parietal cells; pancreatic proteases release B12 from R-binder; B12 binds IF in duodenum, and it is absorbed in ileum
deficiency: can occur with lack of IF or intestinal malabsorption; various symptoms= megaloblastic anemia, subacute combined degeneration of spinal cord tracts, irritability/personality change/depression
macrocytosis anemia with hypersegmentatio nof polymorphonuclear cells |
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Term
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Definition
B12 deficiency due to lack of Intrinsic factor
antibodies commonly seen : anti IF antibodies and anti parietal cell antibodies |
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Term
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Definition
| problems with synthesis of blood cells with B12 or folate deficiency |
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Term
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Definition
| deficiency of hemoglobin production; iron deficiency or thalassaemia |
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Term
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Definition
>100 macrocytic anemia
80-100 normocytic anemia
<80 microcytic anemia |
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Term
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Definition
subsequent early increase in homocysteine--> elevated risk of coronary artery disease
folate lowers homocysteine levels with B12 and B6
folate may mask B12 deficiency anemia; B12 is used to recycle folate so it can revers the anemia if folate is supplemented but there will still be neurological problems from the B12 deficiency |
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Term
| Vitamin C (ascorbic acid) |
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Definition
couples with vitamin E for antioxidant activity
keeps iron in reduced state (more absorbable)
necessary for collagen synthesis
absorbed by sodium dependent transporters
deficiency = scurvy (can't synthesize collagen properly, gum bleeding, poor wound healing, pinpoint hemorrhage) |
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Term
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Definition
| antioxidant use; free radical is absorbed by vitamin E so that it doesn't damage bonds in cell membrane and the electron is transferred to vitamin C on the other side of the membrane |
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