Water Reviewer PDF
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This document reviews the properties of water, including its polarity, ability to act as a solvent, and its role in various buffer systems. It also explains the importance of buffers in maintaining a stable pH, which is crucial for biological processes.
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WATER These are made from a weak acid and its salt WATER (conjugate base) has several unique properties that make it BASIC BUFFERS essential for life...
WATER These are made from a weak acid and its salt WATER (conjugate base) has several unique properties that make it BASIC BUFFERS essential for life These are made from a weak base and its salt WATER’S POLARITY IS DUE TO THE (conjugate acid) UNEVEN DISTRIBUTION OF ELECTRONS EXAMPLES OF BUFFERS IN LIVING BETWEEN OXYGEN AND HYDROGEN ORGANISMS ATOMS. BICARBONATE BUFFER SYSTEM the predominant chemical component of living This system helps maintain the pH of blood. organisms. Its unique physical properties, The bicarbonate buffer system consists of which include the ability to solvate a wide carbonic acid (H₂CO₃) and bicarbonate ions range of organic and inorganic molecules, (HCO₃⁻), which help regulate blood pH derive from water’s dipolar structure and PHOSPHATE BUFFER SYSTEM exceptional capacity for forming hydrogen This system operates in the internal fluids of bonds. cells. It helps maintain pH by neutralizing excess H⁺ ions with hydrogen phosphate or Solvent excess OH⁻ ions with dihydrogen phosphate1 Cohesion the phosphate buffer system operates mainly Adhesion within cells. High Specific Heat High Heat of Vaporization PROTEIN BUFFER SYSTEM Density Proteins can act as buffers by accepting or Polarity-PROPERTY OF WATER ALLOWS donating H⁺ ions. For example, hemoglobin in IT TO DISSOLVE MANY SUBSTANCES red blood cells helps buffer blood pH by The Covalent Bond binding to H⁺ ions1. the strongest force that holds molecules together. Hydrophobic Interaction HEMOGLOBIN BUFFER SYSTEM refers to the tendency of nonpolar compounds Hemoglobin can bind to both oxygen and to self-associate in an aqueous environment. hydrogen ions. When the blood becomes too Electrostatic Interaction acidic, hemoglobin binds to excess H⁺ ions, between oppositely charged groups within or helping to maintain pH balance. During between biomolecules are termed salt bridges. exercise, when more H⁺ ions are produced, SOLVENT hemoglobin helps buffer these ions1. Water is known as the “universal solvent” because it can dissolve many substances. This HENDERSON-HASSELBALCH EQUATION is important for biochemical reactions in our is used to estimate the pH of a buffer solution. bodies, as it helps transport nutrients and waste equation: pH=pKa+log([HA][A−] ) products. BUFFERS Where: are crucial in maintaining the pH balance in pH: The measure of acidity or basicity of the biological systems. solution. A buffer is a solution that resists changes in pH pKa: The acid dissociation constant, a value that when small amounts of acid or base are added. indicates the strength of the acid. It usually consists of a weak acid and its pKa is used to express the relative strengths of conjugate base or a weak base and its conjugate both weak acids and weak bases using a single, acid. unified scale. Buffers can neutralize both acids and bases, A−: The concentration of the conjugate base. maintaining a stable pH by reacting with added HA :The concentration of the weak acid. H⁺ or OH⁻ ions. HOW BUFFERS WORK: The pH ACIDIC BUFFERS The term pH was introduced in 1909 by Sörensen, who defined it as the negative log of the hydrogen ion concentration: This value is also known as the power (English), puissant (French), or potennz (German) of the exponent, hence the use of the term “p.” Low pH values correspond to high concentrations of H+ and high pH values correspond to low concentrations of H+. Acids are proton donors. Strong acids (eg, HCl, H2SO4) completely dissociate into anions and protons even in strongly acidic solutions (low pH). Weak acids dissociate only partially in acidic solutions. Many biochemicals are weak acids Bases are proton acceptors. Strong bases (eg, KOH, NaOH), but not weak bases like Ca(OH)2, are completely dissociated even at high pH.