Micronutrients Flashcards
Vitamins and Minerals
- Organic compounds that are not synthesized by animals and 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 (Vitamin B1)
- Riboflavin (Vitamin B2)
- Niacin (Vitamin B3)
- Biotin
Thiamin (Vitamin B1)
- Produced by microbes, found in plant and animal tissues
- Not stored in the body except when they are attached to enzymes. (co-enzyme; assists in activation of enzyme as it does not have activity on its own)
- needed for glycolysis and TCA cycle.
What steps of glycolysis and TCA cycle is effected by Thiamin (Vitamin B1)?
Pyruvate –> Acetyl-CoA
alpha=Ketoglutarate –> succinyl-CoA
Thiamin deficiency- symptoms and metabolic reasoning
Severe deficiencies can lead to various central and peripheral neurological disorders (such as seizures and paralysis). Happens because a lack of thiamin will affect glycolysis and TCA, which in turn affects aerobic metabolism. Switch to anaerobic metabolism results in build up of lactic acid in the brain = metabolic acidosis
Thiamin deficiency- cause
Due to imbalanced home made diets (it is supplemented in commercial food) OR in raw fish diets in cats (they contain high levels of thiaminase which inactivates thiamin)
Riboflavin (Vitamin B2)
- Produced by plants and microbes. Dietary source: vegetables, yeast, animal liver)
- Core component of Riboflavin 5’-monophosphate (FMN) and Flavin adenine dinucleotide (FAD) (Both FAD and FMN synthesized in liver)
Riboflavin (Vitamin B2)- symptoms and metabolic reasoning
A lack of riboflavin means a decreased amount of FAD which is needed for electron carrier, FADH2. Results in a loss of ATP production from TCA cycle/ETC.
Symptoms: non-life threatening, mucus membrane inflammation, dermatitis, anemia, cataracts
Niacin (Vitamin B3)
Produced from nicotinamide in plants or supplemented in animal foods
- Forms NMN which is needed for NAD+ and NADP+
Niacin (Vitamin B3) deficiency- metabolic reasoning and symptoms
- Niacin forms nicotinate mononucleotide (NMN) which is a precursor of NAD+ and NADP+. Without these precursors, decrease in formation of NADH. NADH is needed for glycolysis, TCA cycle, ETC, beta-oxidation.
Symptoms: pellagra (dermatitis, diarrhea, dementia)
Commonly seen in poultry. Includes Skin and digestive organ disorder, Weight loss, reduced egg production, decrease in hatching
Biotin
Produced by plants and also found in animal tissues
Important for carboxylation reactions including Fatty acid synthesis, Gluconeogenesis (Pyruvate to oxaloacetate), Ketogenesis (from Leucine)
Common elements in the body
- macronutrients (large amounts required in the diet) Ex. Ca, O, Mg, K, Na
- ultra trace elements (almost undetectable, high levels lead to toxicity) Ex. Fl, Pb, B, Ni
- trace elements (required in small amounts but needed for cofactors for enzymes, electrocytes, oxygen binding, structural components) Ex. Zn, Fe, Cu
Role of iron
Iron can easily gain or lose electrons making it an important element for various biological processes . Allows for e- movement.
Important for ETC, and heme molecules
Iron-sulfur clusters
Regulate electron transfer (ETC).
1. e- binds to iron in heme of cytochrome c for movement between complex III and complex IV
2. Heme group also used to transfer e- (after it has been through complex IV) to oxygen to form water
3. Iron-sulphur clusters allow movement of e-‘s through complexes
Heme molecules and Iron
Transfer e- or coordinate oxygen binding. The Fe ion within the heme allows for binding by donating electrons to oxygen.
- Proximal end of hemoglobin polypeptide chain
- Oxygen molecule, which then binds to the distal end of hemoglobin peptide chain
