Inorganic Compounds Chemical Bonds Solutions and pH Cell Chemistry (I) Inorganic Compounds Chemical Bonds Solutions and pH

Introduction Approach this ppt NOT as lecture notes but as an outline of the basic chemistry that you need to know to understand physiology and ease your way into biochemistry. Most of the information can be found in Ch. 1, 2 or 3 of any college Anat. & Physiol. or college Biology textbook. This ppt is NOT a substitute for reading the book.

Chemical Bonds Review the basic facts about: Ionic bond Covalent bond Polar covalent bond Hydrogen bond The next slides illustrates some of these bonds

Some Bonds Illustrated (Marieb, Fig. 2.9)

Hydrogen Bonds Between Water Molecules (Becker Fig. 2.8)

Solubilization of NaCl (Becker Fig. 2.10)

Water: Significance in Physiology Water is essential for life It is a universal solvent in biological systems because of its: Polarity, its cohesiveness, its temperature-stabilizing capacity and its solvent properties Water molecules are held by Hydrogen bonds and these bonds account for its high surface tension, its high boiling point, high specific heat and high heat of vaporization Cells are about 75-85% water by weight and one’s body weight is about 60% water.

Terms Linking Solubility of Solutes in Water The terms hydrophilic, hydrophobic, amphipathic and oil/water partition coefficient are often used to describe the solubility of a solute in water. Hydrophilic solutes are usually polar (they have polar covalent bonds or ionic bonds) and because of their polarity dissolve readily in water Hydrophobic solutes are non-polar, therefore, not soluble in water. They are soluble in organic solvents like benzene. They are rich in non-polar covalent bonds. Amphipathic solutes have a region that is hydrophilic and another one that is hydrophobic.

Surface Tension Allows Insect to Walk on Water

Solutions Know examples of acids, bases & salts Know how to calculate, molarity, osmolarity and equivalentsK Solutions

Solutions Two components: In physiology and in all biological systems: Solvent Solute(s) In physiology and in all biological systems: the solvent is H2O The solutes are many (hundreds) like Nutrients like amino acids, glucose Electrolytes (in physiology = anions & cations) Gases like O2 and CO2 Wastes like urea, creatinine, uric acid Examples of solutions in the body Plasma Interstitial fluid Synovial fluid Urine

Concentration of Solution Concentration is a ratio of the amount of solute(s) in a given volume of solvent Amounts are often expressed in Grams (g) Milligrams (mg) Mole (m) or millimole (mM) Milliequivalent (mEq) Osmole (Osm) or milliosmole (mOsm) Volume is often expressed in Liters (L) Deciliter(100 mL) Milliliters (mL) Microliters Examples: 0.9% NaCl or 135mmole/L NaCl or 135 mEq /L GOAL: Given weight in grams, know how to calculate concentrations in molarity, osmolarity and equivalent

Units for Concentration of Solutions Percent (%): 0.9% Sodium chloride (normal saline) 153 mmole/L Sodium chloride (normal saline) ?? Do these have the same amount of NaCl? Justify your answer Other units commonly used in physiology 0.1-0.4 mg/dL creatinine 70-110 mg/dL glucose 285-295 mOsm/Kg H2O (For what? 136-142 mEq/L Sodium Units for amount of gas 80-105 mmHg Volume % Why should I care about these units? You will constantly run into them in physiology, in reading patients charts and in reading cases.

Inorganic Compounds Characteristic of ionic bonds Most of the chemical in your body and the foods that you consume are compounds that are classified as: Inorganic or Organic Inorganic compounds Small Lack carbon atom (some exceptions? ) Most are composed of minerals like K, Ca, P, Mg, Fe Their atoms are held by ionic bonds Characteristic of ionic bonds They are weak ( easily broken, no enzyme required)

Common Examples of Inorganic Compounds Significant in Physiology Sodium chloride: NaCl Calcium phosphate (Ca)3(PO4)2 Potassium iodide KI Sodium bicarbonate Na(HCO3) Hydrochloric acid HCl Sodium hydroxide NaOH Magnesium hydroxide Mg(OH)2 Calcium chloride CaCl2

Sources of Electrolytes in Physiology In physiology, anions and cations are collectively called electrolytes Salts NaCl, KI, Na(HCO3) Acids (organic and inorganic) HCl, H2CO3 Lactic acid and Acetoacetic acid Bases HCO3- OH-

Ionization of Salts, Acids and Bases In H2O the ionic bonds in acids, salts and bases break and the atoms dissociate into ions (or ionize). Examples Replace question marks with correct answer/s NaCl -> Na+ + Cl- KI -> ?? H2CO3 --> H+ + HCO3- Mg(OH)2  ??

What to Do! Look up/review significance of listed ions in physiology or cell biology. Example: I- (iodide) is essential for thyroxine (T4) synthesis by the thyroid gland. T4 regulates basal metabolic rate. Now do the same for: H+ K+ Na+ Cl- Fe++ Ca++

Questions? Which one is OR which ones are: HCl H2CO3 A) acid(s) B) base(s) C) salt(s) D) electrolytes HCl H2CO3 KI (potassium iodide) Na(HCO3) Ca3(PO4)2 NaCl Na(OH) Mg(OH)2

Inorganic Acids, Bases and Salts Acids, bases and salts in the diet are major sources electrolytes (anions and cations) in body fluids. In H2O acids, bases and salts ionize or dissociate into anions and cations. Examples: Na:Cl -> Na+ + Cl- H:Cl -> H+ + Cl- Na:OH -> Na+ + (OH)- All ions are not NAKED. They are surrounded by a “shell” of H2O (a hydration shell) Hydration shell Illustrated on next slide.

Solubilization of NaCl (Becker Fig. 2.10)

ACIDS, BASES AND PH

Acid: Definition & Examples Substances () that ionize (dissociate) into one or more Hydrogen ion (H+) PLUS one or more anion(s) H+ is also called a proton. Acids are also defined as a proton donors or substances that add proton(s) to a solution. Examples of: Inorganic acids; ---?? Organic acids: ---??

Significance of H+ in Solutions H+ concentration in a solution affects the acidity or alkalinity of the solution: pH =log 1/[H+] = -log [H+] Note log scale and inverse relationship between [H+] and acidity/alkalinity of a solution ? Fill-in blank spaces with the correct term The higher the [H+] the more ---? the solution The lower the [H+] the more ---? The solution

pH: Note Log Scale Know pH of Some Foods Household Goods

Base: Definition and Examples Substance (electrolyte) that ionizes (dissociates) into one or more hydroxide (OH-) ion(s) PLUS one or more cation(s). Also defined as substances that accept or bind to or remove free proton(s) from solutions. HCO3- (What ion is this?) is a major base in body fluids.

Salt: Definition and Examples Substance (electrolyte) dissociate into cations (??) and anions (??) neither of which (??) is H+ or (OH)- Examples of salts? Products of reaction between an acid and a base Example ofsuch a reaction Na(OH) + HCl -- NaCl + H2O

Body Fluid pH Normal body fluid pH is between 7.35 to 7.45. pH below 7.35 is a condition called acidosis pH above 7.45 is a condition called alkalosis Two organs collaborate to maintain normal body fluid pH: The lungs and the kidneys The lungs do so by regulating the excretion rate of CO2 and the kidneys, by regulating the excretion rate of HCO3- ions.

Questions Gastric juice (produced by the stomach) has a pH of 5.0 and plasma pH is 7.0. A) Which one has the lowest H+ concentration: Plasma or gastric juice? B) The difference in concentration is how many times lower? Mr. John Doe has a kidney disease that impairs excretion of HCO3-. A) Would his plasma HCO3- Concentration increase, decrease or remain within the normal range? B) Is he likely to end up with acidosis, alkalosis or neither? Justify your answer. Would you expect hyperventilation or hypoventilation to impact your body fluid pH? Justify your answer

CHEMISTRY I The end