FORM & FUNCTION (Micronutrients) Flashcards
Vitamins and minerals:
-organic compounds that are NOT synthesized by animals
-MUST be supplied in DIET
-function as essential compounds in many biochemical functions
Deficiencies in micronutrients:
-can be associated with various metabolic conditions
B-complex vitamins:
-Thiamin
-Riboflavin
-Niacin
-Biotin
Thiamin:
-vitamin B1
-produced by microbes, found in plant and animal tissues
-not stored in the body (only when attached to enzymes)
*coenzyme
Coenzyme:
-assist in activation of an enzyme
-does NOT have activity on its own
Thiamin in metabolism:
-required for enzymes involved in glycolysis and TCA cycle
*critical for energy metabolism
>pyruvate to acetyl-CoA
>alpha-KG to succinyl-CoA
Thiamin deficiency: caused by
-imbalanced home made diets (supplemented in commercial food)
-raw fist diets in cats
>contain high levels of thiaminase=inactivates thiamin
Severe thiamin deficiencies:
-can lead to various central and peripheral neurological disorders (ex. seizures and paralysis)
*impairs aerobic metabolism ->switch to anaerobic metabolism in the brain ->excess lactic acid production (ex. metabolic acidosis)
**can be fatal if left untreated
Riboflavin:
-B2
-core component of FMN and FAD
-made by plants and microbes
Dietary source of riboflavin:
-vegetable
-yeast
-animal liver
FMN and FAD:
-riboflavin 5’-monophosphate (FMN)
-flavin adenine dinucleotide (FAD)
*synthesized in liver
FAD:
-electron carrier molecules
-is reduced to FADH2 during TCA cycle and beta-oxidation
*passes through ETC to produce 2 ATP molecule
Riboflavin deficiency:
-not life threatening
-associated with various non-specific symptoms
>mucus membrane inflammation
>dermatitis
>anemia
>cataracts
Niacin:
-B3
-forms nicotinate mononucleotide (NMN)=precursor for NAD+ and NADP+
-supplemented in animal foods
-can be made from nicotinamide which is present in most plants
Nicotinamide adenine dinucleotides (NAD+)
-electron carrier in nearly all pathways of energy metabolism
>glycolysis
>TCA cycle
>beta-oxidation
-reduced to NADH
Niacin deficiencies:
-NADH generates ATP (3 protons=3ATP)
-can lead to pellagra
-more commonly in poultry
>skin and digestive organ disorder
>weight loss, reduced egg production, decrease in hatching
Pellagra:
-dermatitis
-diarrhea
-dementia
Biotin:
-produced by plants
-found in animal tissues
-involved in carboxylation reactions
Carboxylation reactions:
-fatty acid synthesis
-gluconeogenesis (pyruvate to oxaloacetate)
-ketogenesis (from Leu)
Common elements in the body:
-macrominerals
-trace elements
-ultra trace elements
Macrominerals:
-large amount required in diet
Trace elements:
-required in smaller amounts
-serve as cofactors
Trace elements: cofactors
-enzymes
-electrolytes
-oxygen binding
-structural components
Ultra trace elements:
-almost undetectable
>high levels lead to toxicity
Role of iron:
-easily gain or lose electrons=important element for various biological processes
-Fe-sulfur cluster regulate ETC
-Heme molecules to transfer electron or coordinate oxygen binding
Ferrous iron:
-Fe2+
-reduced form
- oxidized (lose electron) to Fe3+
Ferric iron:
-Fe3+
-oxidized form
-reduction (gain electron) to Fe2+
Iron: oxygen transport
-heme group contains a ferrous (Fe2+) iron that binds to:
>proximal end of hemoglobin polypeptide chain
>oxygen molecule
Oxygen molecule:
-when heme group binds:
>it binds to the distal end of hemoglobin peptide chain
Oxygen binding:
-oxidizes Fe2+ to Fe3+
>electron is donated to O2- that facilitates distal binding
Iron-sulfur cluster: Fe-S
-core component of ETC
-electron binds to iron in heme of cytochrome c (Fe3+ to Fe2+)
-similar heme group is found in complex IV
>transfers electron to oxygen to form water (cyanide inhibits this process)
Iron deficiency:
-anemia
-important syndrome leading to weakness and lethargy
>due to decreased O2 transport and affects ETC
-young, fast growing animals are particularly vulnerable (younger=metabolism is higher)
Iron overload (excessive absorption):
-toxic leading to hemochromatosis characterized by:
>pigmentation of skin
>pancreatic damaged leading to diabetes
>liver damage leading to cirrhosis
Iodine:
-essential for mammalian thyroid hormone biosynthesis
-iodine to iodide (digestive track): 95% absorption efficiency
Thyroid hormones deficiency:
-leads to goiter formation
-usually stimulates lipid mobilization (lipolysis) and gluconeogenesis
-also stimulate diverse metabolic activities in most tissues influencing basal metabolic rate
