BIOMINERALISATION

BIOMINERALISATION

1. GURUNANAK KHALSA COLLEGE INORGANIC CHEMISTRY (PAPER-2) BY SAKSHI MISHRA M.Sc. PART-2 (SEM-3)

2. BIOMINIRALIZATION

3. WHAT IS BIOMINIRALIZATION The synthesis of inorganic crystalline or amorphous mineral-like materials by living organisms. Among the minerals synthesized biologically in various forms of life are: fluoroapatite,( C a 5 (PO 4 ) 3 (F,OH), hydroxyapatite, magnetite (fe3o4) and calcium carbonate

4. TYPES OF BIOMINIRALIZATION Biologically controlled mineralization (BC M ): cellular activity controls growth, morphology and location of deposition of the mineral. Biologically induced mineralization (BI M ) modification of chemical environment like change in pH, or redox potential etc. Leads to mineralization

5. CALCIUM CARBONATE BIOMINERAL Marine organisms such algae, sponges, corals, molluscs form MgCO 3 containing calcium carbonate in large amounts as a photosynthetic activity. When CO 2 dissolved in water is photosynthetically assimilated the pH value of the surrounding medium rises according to the concentration of CO 3 increases and equillibrium in shifted towards the precipitation of CaCO 3 .

6. Calcium carbonate is most abundant crystalline biomineral in nature. In nature calcium carbonate exists in several forms, calcite and aragonite as the most common ones. examples: carbonates in vertebrates, and calcium phosphates and carbonates in vertebrates. These mineral often form structural features such as sea shells and the bone in mammals and birds.

7. IRON BIOMINERALS The biomineralization of iron oxides is a relatively well documented field of bio-inorganic chemistry. IN ADDITION TO THE IRON (III) HYDROXIDE CONDENSATION PRODUCTS, BIOGENIC IRON OXIDE ALSO EXISTS IN THE FORM OF MAGNETITE (Fe 3 O 4 ). This Fe III,II – containing mineral was detected in the magnetotactic bacteria, in chitos, molluscs, pigeons, bees, fishes and even in humans .

8. CONT… In magnetotactic bacteria under an electron microscope, dark, membrane-coated iron-containing particles i.e. Magnetosomes observed. The magnetosomes are normally arranged as chains along the direction of bacterial movement so that this string of particles may function as biomagnetic compass. TO FORM MAGNETOSOMES IRON IS TAKEN AS CHELATED Fe +3 AND THEN MADE AVAILABLE THROUGH REDUCTION TO Fe +2 . After controlled oxidation a water containing iron(III) oxide precipitates, dehydration first leads to ferrihydrite, and then under partial reduction to magnetic

9. EXAMPLES OF BIOGENIC MINERALS INCLUDE Apatite in bones and teeth Aragonite, calcite , fluorite in vestibular systems (part of the inner ear) of vertebrates Magnetite and greigite formed by Magnetotactic bacteria.

10. Pyrite and marcasite in sedimentary rocks quartz and diamonds formed from bacterial action on fossil fuels (gas, oil, coal) hydroxylapatite formed by mitochondria

11. REFRENCES vogel’s Qualitative Inorganic Analysis 7 th Edition Heinz A. LOWENSTAM, STEPHEN WEINER, OXFORD UNIVERSITY PRESS. D.F. SHRIVER, P.W.ATKINS AND C.H. LANGFORD, INORGANIC CHEMISTRY, 3 RD EDITION OXFORD UNIVERSITY PRESS. Inorganic Chemistry By Gary L. Miessler , 3 rd Edition INTERNET WEBSITES .