Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Matter  The “stuff” of the universe  Anything that has mass and takes up space  States of matter  Solid – has definite shape and volume  Liquid – has definite volume, changeable shape  Gas – has changeable shape and volume

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Energy  The capacity to do work (put matter into motion)  Types of energy  Kinetic – energy in action  Potential – energy of position; stored (inactive) energy PLAY Energy Concepts

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Forms of Energy  Chemical – stored in the bonds of chemical substances  Electrical – results from the movement of charged particles  Mechanical – directly involved in moving matter  Radiant or electromagnetic – energy traveling in waves (i.e., visible light, ultraviolet light, and X-rays)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Energy Form Conversions  Energy is easily converted from one form to another  During conversion, some energy is “lost” as heat

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Composition of Matter  Elements – unique substances that cannot be broken down by ordinary chemical means  Atoms – more-or-less identical building blocks for each element  Atomic symbol – one- or two-letter chemical shorthand for each element

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Properties of Elements  Each element has unique physical and chemical properties  Physical properties – those detected with our senses  Chemical properties – pertain to the way atoms interact with one another

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Major Elements of the Human Body  Oxygen (O),Carbon (C),Hydrogen (H),Nitrogen (N)  Lesser elements make up 3.9% of the body and include:  Calcium (Ca), phosphorus (P), potassium (K), sulfur (S), sodium (Na), chlorine (Cl), magnesium (Mg), iodine (I), and iron (Fe)  Trace elements make up less than 0.01% of the body  They are required in minute amounts, and are found as part of enzymes

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Atomic Structure  The nucleus consists of neutrons and protons  Neutrons – have no charge and a mass of one atomic mass unit (amu)  Protons – have a positive charge and a mass of 1 amu  Electrons are found orbiting the nucleus  Electrons – have a negative charge and 1/2000 the mass of a proton (0 amu)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Models of the Atom  Planetary Model – electrons move around the nucleus in fixed, circular orbits  Orbital Model – regions around the nucleus in which electrons are most likely to be found

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Models of the Atom Figure 2.1

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Identification of Elements  Atomic number – equal to the number of protons  Mass number – equal to the mass of the protons and neutrons  Atomic weight – average of the mass numbers of all isotopes

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Identification of Elements  Isotope – atoms with same number of protons but a different number of neutrons  Radioisotopes – atoms that undergo spontaneous decay called radioactivity

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Identification of Elements: Atomic Structure Figure 2.2

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Identification of Elements: Isotopes of Hydrogen Figure 2.3

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Molecules and Compounds  Molecule – two or more atoms held together by chemical bonds  Compound – two or more different kinds of atoms chemically bonded together

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Mixtures and Solutions  Mixtures – two or more components physically intermixed (not chemically bonded)  Solutions – homogeneous mixtures of components  Solvent – substance present in greatest amount  Solute – substance(s) present in smaller amounts

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Concentration of Solutions  Percent, or parts per 100 parts  Molarity, or moles per liter (M)  A mole of an element or compound is equal to its atomic or molecular weight (sum of atomic weights) in grams

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Colloids and Suspensions  Colloids (emulsions) – heterogeneous mixtures whose solutes do not settle out  Suspensions – heterogeneous mixtures with visible solutes that tend to settle out

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Mixtures Compared with Compounds  No chemical bonding takes place in mixtures  Most mixtures can be separated by physical means  Mixtures can be heterogeneous or homogeneous  Compounds cannot be separated by physical means  All compounds are homogeneous

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Chemical Bonds  Electron shells, or energy levels, surround the nucleus of an atom  Bonds are formed using the electrons in the outermost energy level  Valence shell – outermost energy level containing chemically active electrons  Octet rule – except for the first shell which is full with two electrons, atoms interact in a manner to have eight electrons in their valence shell

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Chemically Inert Elements  Inert elements have their outermost energy level fully occupied by electrons Figure 2.4a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Chemically Reactive Elements  Reactive elements do not have their outermost energy level fully occupied by electrons Figure 2.4b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Types of Chemical Bonds  Ionic  Covalent  Hydrogen

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Ionic Bonds  Ions are charged atoms resulting from the gain or loss of electrons  Anions have gained one or more electrons  Cations have lost one or more electrons

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Formation of an Ionic Bond  Ionic bonds form between atoms by the transfer of one or more electrons  Ionic compounds form crystals instead of individual molecules  Example: NaCl (sodium chloride)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Formation of an Ionic Bond Figure 2.5a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Formation of an Ionic Bond Figure 2.5b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Covalent Bonds  Covalent bonds are formed by the sharing of two or more electrons  Electron sharing produces molecules

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Single Covalent Bonds Figure 2.7a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Double Covalent Bonds Figure 2.7b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Triple Covalent Bonds Figure 2.7c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Polar and Nonpolar Molecules  Electrons shared equally between atoms produce nonpolar molecules  Unequal sharing of electrons produces polar molecules  Atoms with six or seven valence shell electrons are electronegative  Atoms with one or two valence shell electrons are electropositive

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Comparison of Ionic, Polar Covalent, and Nonpolar Covalent Bonds Figure 2.9

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hydrogen Bonds  Too weak to bind atoms together  Common in dipoles such as water  Responsible for surface tension in water  Important as intramolecular bonds, giving the molecule a three-dimensional shape PLAY Hydrogen Bonds

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hydrogen Bonds Figure 2.10a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Chemical Reactions  Occur when chemical bonds are formed, rearranged, or broken  Written in symbolic form using chemical equations  Chemical equations contain:  Number and type of reacting substances, and products produced  Relative amounts of reactants and products

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Examples of Chemical Reactions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Patterns of Chemical Reactions  Combination reactions: Synthesis reactions which always involve bond formation A + B  AB

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Patterns of Chemical Reactions  Decomposition reactions: Molecules are broken down into smaller molecules AB  A + B

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Patterns of Chemical Reactions  Exchange reactions: Bonds are both made and broken AB + C  AC + B

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Oxidation-Reduction (Redox) Reactions  Reactants losing electrons are electron donors and are oxidized  Reactants taking up electrons are electron acceptors and become reduced

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Energy Flow in Chemical Reactions  Exergonic reactions – reactions that release energy  Endergonic reactions – reactions whose products contain more potential energy than did its reactants

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Reversibility in Chemical Reactions  All chemical reactions are theoretically reversible A + B  AB AB  A + B  If neither a forward nor reverse reaction is dominant, chemical equilibrium is reached

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Rate of Chemical Reactions  Temperature – chemical reactions proceed quicker at higher temperatures  Particle size – the smaller the particle the faster the chemical reaction  Concentration – higher reacting particle concentrations produce faster reactions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Rate of Chemical Reactions  Catalysts – increase the rate of a reaction without being chemically changed  Enzymes – biological catalysts

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Biochemistry  Organic compounds  Contain carbon, are covalently bonded, and are often large  Inorganic compounds  Do not contain carbon  Water, salts, and many acids and bases

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Properties of Water  High heat capacity – absorbs and releases large amounts of heat before changing temperature  High heat of vaporization – changing from a liquid to a gas requires large amounts of heat  Polar solvent properties – dissolves ionic substances, forms hydration layers around large charged molecules, and serves as the body’s major transport medium

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PLAY InterActive Physiology ® : Fluid, Electrolyte, and Acid/Base Balance: Introduction to Body Fluids Properties of Water  Reactivity – is an important part of hydrolysis and dehydration synthesis reactions  Cushioning – resilient cushion around certain body organs

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Salts  Inorganic compounds  Contain cations other than H + and anions other than OH –  Are electrolytes; they conduct electrical currents

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Acids and Bases  Acids release H + and are therefore proton donors HCl  H + + Cl –  Bases release OH – and are proton acceptors NaOH  Na + + OH –

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Acid-Base Concentration (pH)  Acidic solutions have higher H + concentration and therefore a lower pH  Alkaline solutions have lower H + concentration and therefore a higher pH  Neutral solutions have equal H + and OH – concentrations

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Acid-Base Concentration (pH)  Acidic: pH 0–6.99  Basic: pH 7.01–14  Neutral: pH 7.00 Figure 2.13

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Buffers  Systems that resist abrupt and large swings in the pH of body fluids  Carbonic acid-bicarbonate system  Carbonic acid dissociates, reversibly releasing bicarbonate ions and protons  The chemical equilibrium between carbonic acid and bicarbonate resists pH changes in the blood PLAY InterActive Physiology ® : Fluid, Electrolyte, and Acid/Base Balance: Acid/Base Homeostasis

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Organic Compounds  Molecules unique to living systems contain carbon and hence are organic compounds  They include:  Carbohydrates  Lipids  Proteins  Nucleic Acids

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Carbohydrates  Contain carbon, hydrogen, and oxygen  Their major function is to supply a source of cellular food  Examples:  Monosaccharides or simple sugars Figure 2.14a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Carbohydrates  Disaccharides or double sugars Figure 2.14b PLAY Disaccharides

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Carbohydrates  Polysaccharides or polymers of simple sugars Figure 2.14c PLAY Polysaccharides

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Lipids  Contain C, H, and O, but the proportion of oxygen in lipids is less than in carbohydrates  Examples:  Neutral fats or triglycerides  Phospholipids  Steroids  Eicosanoids PLAY Fats

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Neutral Fats (Triglycerides)  Composed of three fatty acids bonded to a glycerol molecule Figure 2.15a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Neutral Fats (Triglycerides)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Other Lipids  Phospholipids – modified triglycerides with two fatty acid groups and a phosphorus group Figure 2.15b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Other Lipids  Steroids – flat molecules with four interlocking hydrocarbon rings  Eicosanoids – 20-carbon fatty acids found in cell membranes Figure 2.15c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Representative Lipids Found in the Body  Neutral fats – found in subcutaneous tissue and around organs  Phospholipids – chief component of cell membranes  Steroids – cholesterol, bile salts, vitamin D, sex hormones, and adrenal cortical hormones

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Representative Lipids Found in the Body  Fat-soluble vitamins – vitamins A, E, and K  Eicosanoids – prostaglandins, leukotrienes, and thromboxanes  Lipoproteins – transport fatty acids and cholesterol in the bloodstream

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Amino Acids  Building blocks of protein, containing an amino group and a carboxyl group  Amino group NH 2  Carboxyl groups COOH

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Amino Acids Figure 2.16a–c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Protein  Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds Figure 2.17 Amino acid Dehydration synthesis Hydrolysis Dipeptide Peptide bond +N H H C R H O N H H C R CC H O H2OH2O H2OH2O N H H C R C H O N H C R C H O OH

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Structural Levels of Proteins  Primary – amino acid sequence  Secondary – alpha helices or beta pleated sheets PLAY Chemistry of Life: Proteins: Secondary Structure PLAY Chemistry of Life: Proteins: Primary Structure PLAY Chemistry of Life: Introduction to Protein Structure

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Structural Levels of Proteins  Tertiary – superimposed folding of secondary structures  Quaternary – polypeptide chains linked together in a specific manner PLAY Chemistry of Life: Proteins: Quaternary Structure PLAY Chemistry of Life: Proteins: Tertiary Structure

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Structural Levels of Proteins Figure 2.18a–c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Structural Levels of Proteins Figure 2.18b,d,e

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fibrous and Globular Proteins  Fibrous proteins  Extended and strand-like proteins  Examples: keratin, elastin, collagen, and certain contractile fibers  Globular proteins  Compact, spherical proteins with tertiary and quaternary structures  Examples: antibodies, hormones, and enzymes

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Protein Denuaturation  Reversible unfolding of proteins due to drops in pH and/or increased temperature Figure 2.19a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Protein Denuaturation  Irreversibly denatured proteins cannot refold and are formed by extreme pH or temperature changes Figure 2.19b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Molecular Chaperones (Chaperonins)  Help other proteins to achieve their functional three-dimensional shape  Maintain folding integrity  Assist in translocation of proteins across membranes  Promote the breakdown of damaged or denatured proteins

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Characteristics of Enzymes  Most are globular proteins that act as biological catalysts  Holoenzymes consist of an apoenzyme (protein) and a cofactor (usually an ion)  Enzymes are chemically specific  Frequently named for the type of reaction they catalyze  Enzyme names usually end in -ase  Lower activation energy

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Characteristics of Enzymes Figure 2.20

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Mechanism of Enzyme Action  Enzyme binds with substrate  Product is formed at a lower activation energy  Product is released PLAY How Enzymes Work

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.21 Active site Amino acids Enzyme (E) Enzyme-substrate complex (E-S) Internal rearrangements leading to catalysis Dipeptide product (P) Free enzyme (E) Substrates (S) Peptide bond H2OH2O +

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nucleic Acids  Composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus  Their structural unit, the nucleotide, is composed of N-containing base, a pentose sugar, and a phosphate group  Five nitrogen bases contribute to nucleotide structure – adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U)  Two major classes – DNA and RNA

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Deoxyribonucleic Acid (DNA)  Double-stranded helical molecule found in the nucleus of the cell  Replicates itself before the cell divides, ensuring genetic continuity  Provides instructions for protein synthesis

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Structure of DNA Figure 2.22a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Structure of DNA Figure 2.22b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Ribonucleic Acid (RNA)  Single-stranded molecule found in both the nucleus and the cytoplasm of a cell  Uses the nitrogenous base uracil instead of thymine  Three varieties of RNA: messenger RNA, transfer RNA, and ribosomal RNA

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Adenosine Triphosphate (ATP)  Source of immediately usable energy for the cell  Adenine-containing RNA nucleotide with three phosphate groups

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Adenosine Triphosphate (ATP) Figure 2.23

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.24 Solute Solute transported Contracted smooth muscle cell Product made Relaxed smooth muscle cell Reactants Membrane protein P PiPi ATP PXX Y Y + (a) Transport work (b) Mechanical work (c) Chemical work PiPi PiPi + ADP