Bioscience and Biotechnology - A Bioresearch Protocol to Practically Learn and Engineer the Biotics: buffers buffers | Bioscience and Biotechnology - A Bioresearch Protocol to Practically Learn and Engineer the Biotics

Buffers

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<strong style="border: 0px; font-family: inherit; font-size: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">Buffer:</strong></h2>
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<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Buffers are defined as solutions which resists small change in pH by adding small amount of acid or base.</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">A buffer usually consists of a weak acid and its salt (fore eg, acetic acid and sodium acetate) or a weak base and its salt (for eg, ammonium hydroxide and ammonium chloride).</li>
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Mechanism of buffer action:</h3>
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CH3COOH  ß——à CH3COO- + H+</div>
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CH3COONa  ß—-à CH3COO- + Na+</div>
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<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">When HCL is added H+ ion combines with CH3COO- and resists change in pH. Similarly when a base (NaOH) is added H+ ion and OH- ion combines to form H2o which also rsist pH change. Hence the buffer solution resist change in pH when adding small amount of acid or base.</li>
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Buffering capacity:</h2>
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<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">The efficiency of a buffer in maintaining a constant pH on addition of acid or base is referred to as buffering capacity. It mostly depends on the concentration of buffering component. The maximum buffering capacity is achieved by keeping same concentration of acid and its salt or base and its salt.</li>
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Properties of good buffer:</h2>
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<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">The buffer should be non-toxic</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">The buffer should be able to penetrate cell membrane and should not absorbs light at UV or visible region</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Buffer should have adequate buffering capacity</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Buffer should not form insoluble complex with any anions or cations in the reaction.</li>
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<strong style="border: 0px; font-family: inherit; font-size: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;"> Role of buffer in vitro:</strong></h2>
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<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Acid-base buffer helps in tissue or organ preservation ( eg phosphate buffer)</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">In tissue culture, the optimum pH is maintained by buffers. For example HEPES buffer is widely used in cell culture because it is better at maintaining physiological pH despite change in CO2 concentration in media.</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">HEPES also maintains enzyme structure and function at low temperature</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Buffer are used in fermentation process</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">It is also used for setting correct condition for dyes used in coloring fabrics</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Buffer is used to calibrate pH meter</li>
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<strong style="border: 0px; font-family: inherit; font-size: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">Role of buffer in vivo</strong></h2>
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There are three buffer system in human body to maintain acid-balance.</div>
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<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Bicarbonate buffer</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Phosphate buffer</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Protein buffer</li>
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Bicarbonate buffer:</h3>
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<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Sodium bicarbonate and carbonic acid constitute bicarbonate buffer. It is the most predominant buffer system in plasma.</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">It is extracellular buffer</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">It helps in maintaining blood pH 7.4</li>
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Phosphate buffer:</h3>
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<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Sodium dihydrogen phosphate and disodium hydrogen phosphate constitute phosphate buffer.</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">It is intracellular buffer</li>
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Protein buffer:</h3>
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<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">The plasma protein and hemoglobin together constitute protein buffer system of blood.</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Th ebuffering capacity of protein buffer depends upon pKa of amino acids.</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">The imidazole group of histidine (pKa= 6.7) is the most effective contributor of protein buffer.</li>
<li style="border: 0px; font: inherit; margin: 0px 0px 5px; padding: 0px; vertical-align: baseline;">Hemoglobin of RBCs is also an important buffer. Hb binds to H+ ions and helps to transport CO2 as HCo3- ion with minimum change in pH. In lungs Hb combines with O2 then H+ ion is released and combine with HCO3- to form carbonic acid (HCO3-). Later carbonic acid dissociates to release CO2.</li>
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buffers Buffers

Buffer: Buffers are defined as solutions which resists small change in pH by adding small amount of acid or base. A buffer usually co...