The phosphate buffer consists of phosphoric acid H
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Question: Buffer solutions are necessary to keep the correct pH for enzymes in many organisms to work. Many enzymes work only under very precise conditions; if the pH moves outside of a narrow range, the enzymes slow or stop working and can denature. Research and describe a situation where a buffer solution is necessary in the human body. Buffers are truly amazing as they are able to maintain the pH of a person’s body even with the addition of acids or bases allowing a person's body to function properly.There are many specific buffer systems in the human body, one of them being the phosphate buffer. The internal environment of all cells contain the phosphate buffer, so how does our body maintain intracellular pH? Phosphate is an effective physiological buffer because its pKa is near physiological pH. The pK for the phosphate buffer is 6.8, which allows this buffer to function within its effective buffering range at physiological pH. The phosphate buffer system consists of dihydrogen phosphate ions as the hydrogen ion donor ( acid ) and hydrogen phosphate ion as the ion acceptor ( base ) . Along with dihydrogen phosphate ion (H2PO4-) and H+ the phosphate buffer consists of phosphoric acid (H3PO4) in equilibrium. If additional hydroxide ions enter the cellular fluid, they are neutralised by the dihydrogen phosphate ion. If extra hydrogen ions enter the cellular fluid, then they are neutralised by the hydrogen phosphate ion. Phosphate buffer is the most predominant buffer in urine. The developing urine contains NaH2PO4 in the same concentration as present in blood plasma. NaH2PO4 is actually the salt in the urine. In the developing urine the ratio of H2PO4-/HPO4 -2 is 1:4, therefore the right side of the equilibrium is favored. When the urine is acidified (hydrogen ions added), the increase in H+ ion causes the equilibrium to shift left to form H2PO4-. Phosphates are found in the blood in two forms: sodium dihydrogen phosphate (Na2H2PO4−), which is a weak acid, and sodium monohydrogen phosphate (Na2HPO42-), which is a weak base. When Na2HPO42- comes into contact with a strong acid, such as HCl, the base picks up a second hydrogen ion to form the weak acid Na2H2PO4− and NaCl. When Na2HPO42− (the weak acid) comes into contact with a strong base, such as sodium hydroxide (NaOH), the weak acid reverts back to the weak base and produces water. Acids and bases are still present, but they hold onto the ions. The phosphate buffer only plays a minor role in the blood because H3PO4 and H2PO4- are found in very low concentration in the blood, so this allows for phosphate buffer to work with other buffer systems to maintain the pH of the blood during activities such as exercise. Buffers are able to effectively adapt to the slight changes in pH of the body allowing the body’s other systems such as the circulatory system to function. Bibliography: http://chemistry.elmhurst.edu/vchembook/262kidbuffer.html http://chemistry.elmhurst.edu/vchembook/262kidbuffer.html http://www.chemistry.wustl.edu/~edudev/LabTutorials/Buffer/Buffer.html Download 7.86 Kb. Share with your friends:
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