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Biochemistry

Monosaccharides: Aldoses (e.g., glucose) have an aldehyde at one end

They are classified acc to the number of carbon atoms present

Trioses, tetroses, pentose ( ribose, deoxyribose), hexoses  (glucose, galactose, fructose) Heptoses (sedoheptulose)

Glyceraldehyde simplest aldose

Ketoses (e.g., fructose) have a keto group, usually at C 2.

Dihydroxyacetone simplest Ketoses

The higher sugar exists in ring form rather than chain form

Furan  : 4 carbons and 1 oxygen

Pyrans : 5 carban and 1 oxygen

 These result from formation of hemiacital linkage b/w carbonyl and an alcohol group

Biotin

 Biotin helps release energy from carbohydrates and aids in the metabolism of fats, proteins and carbohydrates from food.

RDA The Adequate Intake (AI) for Biotin is 30 mcg/day for adult males and females

Biotin Deficiency Biotin deficiency is uncommon under normal circumstances, but symptoms include fatigue, loss of appetite, nausea, vomiting, depression, muscle pains, heart abnormalities and anemia.

FLUORIDE

The safe limit of fluorine is about 1PPM in water. But excess of fluoride causes Flourosis

Flourosis is more dangerous than caries. When Fluoride content is more than 2 PPM, it will cause chronic intestinal upset, gastroenteritis, loss of weight, osteosclerosis, stratification and discoloration of teeth

Carbohydrates (glycans) have the  basic composition

  • Monosaccharides - simple sugars,  with multiple hydroxyl groups. Based on the number of carbons (e.g., 3, 4, 5, or 6) a monosaccharide is a triose, tetrose, pentose, or hexose, etc.
  • Disaccharides - two monosaccharides covalently linked
  • Oligosaccharides - a few monosaccharides covalently linked.
  • Polysaccharides - polymers consisting of chains of monosaccharide or disaccharide units

LIPOPROTIENS

Lipoproteins Consist of a Nonpolar Core & a Single Surface Layer of Amphipathic Lipids

The nonpolar lipid core consists of mainly triacylglycerol and cholesteryl ester and is surrounded by a single surface layer of amphipathic phospholipid and cholesterol molecules .These are oriented so that their polar groups face outward to the aqueous medium. The protein moiety of a lipoprotein is known as an apolipoprotein or apoprotein,constituting nearly 70% of some HDL and as little as 1% of Chylomicons. Some apolipoproteins are integral and cannot be removed, whereas others can be freely transferred to other lipoproteins.

There  re five types of lipoproteins, namely chylomicrons, very low density lipoproteins(VLDL)  low density lipoproteins (LDL), high density Lipoproteins (HDL) and free fatty acid-albumin complexes.

Role of Coenzymes

The functional role of coenzymes is to act as transporters of chemical groups from one reactant to another.

Ex. The hydride ion (H+ + 2e-) carried by NAD or the mole of hydrogen carried by FAD;

The amine (-NH2) carried by pyridoxal phosphate

Enzymes are protein catalyst produced by a cell and responsible ‘for the high rate’ and specificity of one or more intracellular or extracellular biochemical reactions.

Enzymes are biological catalysts responsible for supporting almost all of the chemical reactions that maintain animal homeostasis. Enzyme reactions are always reversible.

The substance, upon which an enzyme acts, is called as substrate. Enzymes are involved in conversion of substrate into product.

Almost all enzymes are globular proteins consisting either of a single polypeptide or of two or more polypeptides held together (in quaternary structure) by non-covalent bonds. Enzymes do nothing but speed up the rates at which the equilibrium positions of reversible reactions are attained.

 In terms of thermodynamics, enzymes reduce the activation energies of reactions, enabling them to occur much more readily at low temperatures - essential for biological systems.

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