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Basic Chemistry Chapter 2 Introduction • Since chemicals compose the body, & the sum of the chemical reactions that takes place in the body is called metabolism, it is important to be familiar with basic chemistry. Matter • Anything that has mass & occupies space • 3 States – solid, liquid, gas Energy • Capacity to do work • 2 Types – kinetic (motion) & potential (stored) • 4 Forms the body uses – Chemical – stored in bonds of chemicals food • Electrical – movement of charged particles – ions • Mechanical – moving matter - muscles • Radiant – travels in waves – EM spectrum Copyright Pearson Prentice Hall Elements A chemical element is a pure substance that consists entirely of one type of atom. 112 elements are known with certainty. 96% of the mass of a human is made up of Carbon, Hydrogen, Oxygen, and Nitrogen. Atoms Copyright Pearson Prentice Hall The study of chemistry begins with the basic unit of matter, the atom. Protons and Neutrons Copyright Pearson Prentice Hall The subatomic particles that make up Electrons atoms are • Protons (+) • Neutrons (0) • Electrons (-) Copyright Pearson Prentice Hall The number of protons in an atom of an element is the element's atomic number Mass number is the number of protons and neutrons in the nucleus of an atom Copyright Pearson Prentice Hall Atoms of the same element that differ in the number of neutrons they contain are known as isotopes. Copyright Pearson Prentice Hall Because they have the same number of electrons, all isotopes of an element have the same chemical properties. Radioisotopes • Isotopes that exhibit radioactive behavior • Used to tag biological molecules so that they can be traced through the body for medical diagnosis and treatment • Xrays, Nuclear Medicine, PET Scans, CT Scans, MRI Molecules Compounds • two or more atoms held together by chemical bonds. • H (atom) + H (atom) → H2 (molecule) • two or more different elements, the atoms of which are chemically united • 4H + C = CH4 (methane) Chemical Bonds Copyright Pearson Prentice Hall The atoms in compounds are held together by chemical bonds. The electrons that are available to form bonds are called valence electrons. Copyright Pearson Prentice Hall The main types of chemical bonds are: • ionic bonds • covalent bonds An ionic bond is formed when one or more electrons are transferred from one atom to another. These positively and negatively charged atoms are known as ions. Ionic bonds are common in salts. Copyright Pearson Prentice Hall Ionic Bonds • double bond • triple bond Copyright Pearson Prentice Hall A covalent bond forms when electrons are shared between atoms. • single covalent bond Weak bonds that bind water molecules or different parts of the same molecule. They are common in large, complex organic molecules (proteins & nucleic acids). Copyright Pearson Prentice Hall Hydrogen Bonds Patterns of Chemical Reactions 1. Synthesis – A+B = AB; Two or more atoms form a larger atom 2. Decomposition - AB→ A+B; Molecules are broken down 3. Exchange – AB + C →AC + B; A switch is made Factors Increasing the Rate of Reactions 1. Increase Temperature 2. Increase Concentration of reacting particles 3. Decrease particle size 4. Presence of Catalyst Biochemistry • Inorganic • Lack Carbon • Small, simple molecules • Ex: Water, Salts, Acids, Bases • Organic • Have Carbon • Fairly large, covalently boned molecules • Carbohydrates, Lipids, Proteins, Nucleic Acids Water • Most abundant inorganic compound in the body • Accounts for about two-thirds of body weight • Properties • High heat capacity • Polarity/solvent properties • Chemical reactivity • Cushioning Salts • Ionic compound that dissociates into charged particles (other than hydrogen or hydroxyl ions) when dissolved in water • Called electrolytes • Vital to body functioning A water molecule is neutral, but can react to form hydrogen and hydroxide ions. H2O H+ + OHpH – measure of how acidic or basic a solution is Copyright Pearson Prentice Hall Acids, Bases, and pH Acids and Bases • Like salts, acids and bases are electrolytes. • That is, they ionize and then dissociate in water and can then conduct an electrical current. Chemists devised a measurement system called the pH scale to indicate the concentration of H+ ions in solution. The pH scale ranges from 0 to 14. Copyright Pearson Prentice Hall The pH scale The pH Scale Acid below 7; more H+ than OHBase above 7; less H+ than OH- Copyright Pearson Prentice Hall At a pH of 7, the concentration of H+ ions and OH- ions is equal - Neutral Buffers • Living cells are extraordinarily sensitive to even slight changes in pH; and acid-base balance is carefully regulated by the kidneys, lungs, and a number of chemicals called buffers, which are present in body fluids. • Buffer - a substance or substances that help to stabilize the pH of a solution. Types of Organic Compounds • 4 main types of organic compounds are: Carbohydrates – known as sugars, polar molecules, most dissolve in water Lipids – fats, nonpolar, do not dissolve in water Nucleic acids – DNA and RNA Proteins – amino acids, muscles, enzymes and hair 3 Types of Carbohydrates • Monosaccharide: one simple sugar. Examples are glucose, fructose(fruit sugar), galactose(milk sugar) • The formula for glucose is C6H12O6. Plants use this during photosynthesis 3 Types of Carbohydrates Disaccharide: two simple sugars joined by a saccharide bond. ◦ Examples are sucrose(table sugar), lactose(milk sugar), and maltose (malt beverage sugar) Polysaccharide: three or more monosaccharides combined. ◦ Examples are cellulose(cell walls), chitin (exoskeleton), glycogen (stores glucose in liver cells), starch (stores glucose in roots of plants) Lipids Lipids are fats, waxes, phospholipids, and steroids. Lipids contain carbon, hydrogen and oxygen but have fewer oxygen atoms than carbohydrates Building blocks are glycerol and three fatty acids. Lipids are used for protection, cushion, structure, insulation, and energy storage. Fats ◦ Saturated contains the maximum amount of hydrogens – solid at room temperature – animal fats ◦ Unsaturated does not contain maximum amounts of hydrogen so double bonds exists – liquids at room temperature- oils Phospholipids make up cell membranes ◦ Consists of two fatty acids and a phosphate group Steroids contain a 4-ringed backbone ◦ Examples: cholesterol and steroids (hormones) Waxes – used to form waterproof coverings on leaves, skin, or fur ◦ Example: beeswax, ear wax Proteins are composed of carbon, hydrogen, oxygen, and nitrogen (sulfur is found in two amino acids) The building blocks of protein are amino acids held together by a peptide bond. Proteins Proteins Function in immunity, building structures, hormones, enzymes, transporting substances Examples of proteins are antibodies, muscles, ligaments, tendons, and hair. • Enzymes are made of proteins • Enzymes biological catalysts that enables chemical reactions to take place in the body • End in –ase • Enzymes speed up chemical reactions that take place in cells Enzyme Nucleic Acids Copyright Pearson Prentice Hall polymers assembled from individual monomers known as nucleotides. Nucleic Acids Nucleotides consist of three parts: • a 5-carbon sugar (Carbon, hydrogen, & oxygen) • a phosphate group • adenine, cytosine, guanine, and thymine for DNA and adenine, cytosine, guanine, and uracil for RNA Copyright Pearson Prentice Hall • a nitrogenous base Nucleic acids store and transmit hereditary, or genetic information. Examples: ribonucleic acid (RNA) Copyright Pearson Prentice Hall deoxyribonucleic acid (DNA) ATP • a modified nucleotide; it consists of an adenine base, ribose sugar, and three phosphate groups • the universal energy compound used by all cells of the body