ch02_APR_lecture_ppt.pptx

Chapter 02 Lecture Outline See separate PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes. ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom...

Chapter 02 Lecture Outline See separate PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes. ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Introduction Biochemistry – The study of the molecules that compose living organisms – Carbohydrates, fats, proteins, and nucleic acids – Useful for understanding cellular structures, basic physiology, nutrition, and health ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  2.1 Atoms, Ions, and Molecules Expected Learning Outcomes – Identify the elements of the body from their symbols. – Distinguish between elements and compounds. – State the functions of minerals in the body. – Explain the basis for radioactivity and the types of hazards of ionizing radiation. – Distinguish between ions, electrolytes, and free radials. – Define the types of chemical bonds. ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  The Chemical Elements 1 Element—simplest form of matter to have unique chemical properties Atomic number of an element—number of protons in its nucleus – Periodic table Elements arranged by atomic number Elements represented by one- or two-letter symbols – 24 elements have biological role 6 elements = 98.5% of body weight – Oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus Trace elements in minute amounts, but play vital roles ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  The Chemical Elements 2 Minerals—inorganic elements extracted from soil by plants and passed up food chain to humans – Ca, P, Cl, Mg, K, Na, and S – Constitute about 4% of body weight – Important for body structure (Ca crystals in teeth, bones, etc.) – Important for enzymes’ functions – Electrolytes—mineral salts needed for nerve and muscle function ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Atomic Structure Neils Bohr proposed planetary model of atomic structure in 1913 Nucleus—center of atom – Protons: single (+) charge; mass = 1 atomic mass unit (amu) – Neutrons: no charge; mass = 1 amu – Atomic mass is approximately equal to total number of protons and neutrons Electrons—in concentric clouds surrounding nucleus – Electrons: single (-) charge, very low mass An atom is electrically neutral, as number of electrons equals number of protons Valence electrons orbit in the outermost shell and determine chemical bonding properties of an atom ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Copyright © McGraw-Hill Education. Permission required for reproduction or display. Carbon (C) Nitrogen (N) ,, ,, Atomic number Atomic number = 6 = 7 Atomic mass = Atomic mass = 12 14 Sodium (Na) ,, Atomic number Bohr Planetary Models of = 11 Atomic mass = Elements 23 Figure 2.1 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Isotopes and Radioactivity 1 Isotopes—varieties of an element that differ only in the number of neutrons – Extra neutrons increase atomic weight – Isotopes of an element are chemically similar because they have the same number of valence electrons Atomic weight (relative atomic mass) of an element accounts for the fact that an element is a mixture of isotopes ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Isotopes Copyright © McGraw-Hill Education. Permission required for reproduction or display. of Hydrogen Hydrogen (, , Deuterium Tritium (, , ) ) (, , ) Figure 2.2 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Isotopes and Radioactivity 2 Radioisotopes – Unstable isotopes that decay and give off radiation – Every element has at least one radioisotope Intense radiation can be ionizing (ejects electrons, destroys molecules, creates free radicals) and can cause genetic mutations and cancer – Examples: UV radiation, X-rays, alpha particles, beta particles, gamma rays Physical half-life of radioisotopes – Time required for 50% to decay to a stable state Biological half-life of radioisotopes – Time required for 50% to disappear from the body ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Isotopes and Radioactivity 3 Unit of radiation dosage in sievert (Sv) – 5 Sv or more is usually fatal – Background radiation = natural sources such as radon gas and cosmic rays 2.4 millisieverts (mSv) per year is average background exposure – Artificial sources of radiation = X-rays, color TVs, etc… 0.6 mSV is average exposure from artificial sources – U.S. government sets standard acceptable exposure at 50 mSv per year ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Radiation and Madame Curie First woman to Copyright © McGraw-Hill Education. Permission required for reproduction or display. receive Nobel Prize (1903) First woman in world to receive a Ph.D. – Coined term radioactivity – Discovered radioactivity of polonium and radium – Trained physicians in use of X-rays and pioneered radiation therapy as cancer treatment © Science Source Died of radiation poisoning at age 67 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior Ions, Electrolytes, and Free Radicals 1 Ion—charged particle (atom or molecule) with unequal number of protons and electron Ionization—transfer of electrons from one atom to another Anion—particle that gains electron(s) (net negative charge) Cation—particle that loses electron(s) (net positive charge) Ions with opposite charges are attracted to each other ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Copyright © McGraw-Hill Education. Permission required for reproduction or display. Ionization 1) Transfer of an electron from a sodium atom to a chlorine atom Figure 2.4 2) The charged sodium ion and chloride ion that result ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior Ions, Electrolytes, and Free Radicals 2 Electrolytes—substances that ionize in water and form solutions capable of conducting electric current Electrolyte importance – Chemical reactivity, osmotic effects, electrical excitability of nerve and muscle – Electrolyte balance is one of the most important considerations in patient care (imbalances can lead to coma or cardiac arrest) ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior Ions, Electrolytes, and Free Radicals 3 Free radicals—short-lived particles with an unusual number of electrons – Produced by normal metabolic reactions, radiation, certain chemicals – Trigger reactions that destroy molecules, and can cause cancer, death of heart tissue, and aging Antioxidants – Chemicals that neutralize free radicals – Superoxide dismutase (SOD) is an antioxidant enzyme in the body – Selenium, vitamin E, vitamin C, and carotenoids are antioxidants obtained through the diet ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Molecules and Chemical Bonds 1 Molecule—chemical particle composed of two or more atoms united by a chemical bond Compound—molecule composed of two or more different elements Molecular formula—identifies constituent elements and how many atoms of each are present Structural formula—identifies location of each atom Isomers—molecules with identical molecular formulae but different arrangement of their atoms ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Structural Isomers, Ethanol and Ethyl Ether Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.5 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Molecules and Chemical Bonds 2 The molecular weight (MW) of a compound is the sum of the atomic weights of its atoms. Calculate: MW of glucose Molecular weight (MW) 180 amu ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Molecules and Chemical Bonds 3 Chemical bonds—hold atoms together within a molecule or attract one molecule to another Most important types of chemical bonds: ionic bonds, covalent bonds, hydrogen bonds, van der Walls forces Ionic bonds Attractions between anions and cations (example, NaCl) Electrons donated from one atom to another Easily broken by water ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Single Covalent Bond Copyright © McGraw-Hill Education. Permission required for reproduction or display. (a ) Figure 2.6a ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Double Covalent Bond Copyright © McGraw-Hill Education. Permission required for reproduction or display. Carbon dioxide molecule (b ) Figure 2.6b ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Molecules and Chemical Bonds 4 Nonpolar bond: electrons shared equally (strongest bond) Polar bond: electrons shared unequally (spend more time near oxygen) ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Nonpolar and Polar Covalent Bonds Copyright © McGraw-Hill Education. Permission required for reproduction or display. Nonpolar covalent bond (a ) Polar covalent bond (b ) Figure 2.7 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Molecules and Chemical Bonds 5 Hydrogen bond—a weak attraction between a slightly positive hydrogen atom in one molecule and a slightly negative oxygen or nitrogen atom in another – Water molecules are attracted to each other by hydrogen bonds – Large molecules (DNA and proteins) shaped by hydrogen bonds within them – Important to physiology ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Hydrogen Bonding of Water Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.8 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Molecules and Chemical Bonds 6 Van der Waals forces—weak, brief attractions between neutral atoms – Fluctuation in electron density within an atom creates polarity for a moment, and attracts adjacent atom for a very short time – Only 1% as strong as a covalent bond, but important in physiology (example, protein folding) ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  2.2 Water and Mixtures Expected Learning Outcomes – Define mixture and distinguish between mixtures and compounds. – Describe the biologically important properties of water. – Show how three kinds of mixtures differ from each other. – Define acid and base and interpret the pH scale. – Discuss some ways in which the concentration of a solution can be expressed, and the kinds of information we can derive from the different units of measure. ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Water and Mixtures Mixtures—physically blended but not chemically combined Body fluids are complex mixtures of chemicals Most mixtures in our bodies consist of chemicals dissolved or suspended in water Water is 50% to 75% of body weight – Depends on age, sex, fat content, etc. ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Water 1 Polar covalent bonds and a V-shaped molecule give water a set of properties that account for its ability to support life. – Solvency – Cohesion – Adhesion – Chemical reactivity – Thermal stability ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Water 2 Solvency—ability to dissolve other chemicals Water is called the universal solvent – Hydrophilic—substances that dissolve in water Molecules must be polarized or charged (e.g., sugar) – Hydrophobic—substances that do not dissolve in water Molecules are nonpolar or neutral (e.g., fats) Metabolic reactions depend on solvency of water ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Water and Hydration Spheres Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.9 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Water 3 Attractions to water molecules overpower the ionic bond in NaCl – Water forms hydration spheres around each ion and dissolves them – Water’s negative pole faces , its positive pole faces ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Water 4 Adhesion—tendency of one substance to cling to another – Water adheres to large membranes reducing friction around organs Cohesion—tendency of like molecules to cling to each other – Water is very cohesive due to its hydrogen bonds – Surface film on surface of water is due to molecules being held together by surface tension ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Water 5 Chemical reactivity—ability to participate in chemical reactions – Water ionizes into and – Water ionizes many other chemicals (acids and salts) – Water is involved in hydrolysis and dehydration synthesis reactions ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Water 6 Water’s thermal stability helps stabilize the internal temperature of the body – Water has high heat capacity—the amount of heat required to raise the temperature of 1 g of a substance by 1°C – Calorie (cal)—the amount of heat that raises the temperature of 1 g of water 1°C Hydrogen bonds inhibit temperature increases by inhibiting molecular motion – Effective coolant 1 mL of perspiration removes 500 calories ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior Solutions, Colloids, and Suspensions 1 Solution—consists of particles called the solute mixed with a more abundant substance (usually water) called the solvent Solute can be gas, solid, or liquid Solutions are defined by the following properties: – Solute particles under 1 nm – Solute particles do not scatter light – Will pass through most membranes – Will not separate on standing ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior A Solution, a Colloid, and a Suspension Copyright © McGraw-Hill Education. Permission required for reproduction or display. (a-d): © Ken Saladin Figure 2.10 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior Solutions, Colloids, and Suspensions 2 Colloids in the body are often mixtures of protein and water – Many can change from liquid to gel state within and between cells Colloids are defined by the following physical properties: – Particles range from 1–100 nm in size – Scatter light and are usually cloudy – Particles too large to pass through semipermeable membrane – Particles remain permanently mixed with the solvent when mixture stands ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior Solutions, Colloids, and Suspensions 3 Suspension – Defined by the following physical properties: Particles exceed 100 nm Too large to penetrate selectively permeable membranes Cloudy or opaque in appearance Separates on standing – Example: blood cells are suspended in plasma Emulsion – Suspension of one liquid in another Example: fat in breast milk is an emulsion ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Acids, Bases, and pH 1 An acid is a proton donor (releases ions in water) A base is a proton acceptor (accepts ions) – Many bases release pH is a measure derived from the molarity of – a pH of 7.0 is neutral pH – a pH of less than 7 is acidic solution – a pH of greater than 7 is basic solution ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Acids, Bases, and pH 2 pH—measurement of molarity of ([H+]) on a logarithmic scale – thus A change of one number on the pH scale represents a 10-fold change in concentration – A solution with pH of 4.0 is 10 times as acidic as one with pH of 5.0 Buffers—chemical solutions that resist changes in pH – Maintaining normal (slightly basic) pH of blood is crucial for physiological functions ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  The pH Scale Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.11 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Other Measures of Concentration 1 How much solute in a given volume of solution? Weight per volume – Weight of solute in a given volume of solution IV saline: 8.5 g NaCl per liter of solution Common biology units: milligrams per deciliter (mg/dL) – Example: serum cholesterol may be 200 mg/dL Percentages – Might be weight of solute (solid) per volume Example: 5% dextrose solution has 5 g solute in 100 mL solution – Might be volume of solute (liquid) per volume of solution ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Other Measures of Concentration 2 Electrolytes are crucial for heart, nerve, muscle Measured in equivalents (Eq) – 1 Eq is the amount of electrolyte that will neutralize 1 mole of or ions – Often expressed as milliequivalents (mEq/L) – Multiply molar concentration x valence of the ion ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  2.3 Energy and Chemical Reactions Expected Learning Outcomes – Define energy and work, and describe some types of energy. – Understand how chemical reactions are symbolized by chemical equations. – List and define the fundamental types of chemical reactions. – Identify the factors that govern the speed and direction of a reaction. – Define metabolism and its two subdivisions. – Define oxidation and reduction, and relate these to changes in the energy content of a molecule. ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Energy and Work 1 Energy—capacity to do work – To do work means to move something – All body activities are forms of work Potential energy—energy stored in an object, but not currently doing work – Example: water behind a dam – Chemical energy—potential energy in molecular bonds – Free energy—potential energy available in a system to do useful work ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Energy and Work 2 Kinetic energy—energy of motion, doing work – Example: water flowing through a dam, generating electricity – Heat—kinetic energy of molecular motion – Electromagnetic energy—the kinetic energy of moving “packets” of radiation called photons ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Classes of Chemical Reactions 1 Chemical reaction—a process in which a covalent or ionic bond is formed or broken Chemical equation—symbolizes the course of a chemical reaction – Reactants (on left) products (on right) Classes of chemical reactions – Decomposition reactions – Synthesis reactions – Exchange reactions ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Classes of Chemical Reactions 2 Decomposition reactions—large molecule breaks down into two or more smaller ones – AB A + B Synthesis reactions—two or more small molecules combine to form a larger one – A + B AB Exchange reactions—two molecules exchange atoms or group of atoms – AB+CD ABCD AC + BD Stomach acid (HCl) and sodium bicarbonate from the pancreas combine to form NaCl and ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Decomposition Reaction Copyright © McGraw-Hill Education. Permission required for reproduction or display. (a) Decomposition reaction Figure 2.12a ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Synthesis Reaction Copyright © McGraw-Hill Education. Permission required for reproduction or display. (b) Synthesis reaction Figure 2.12b ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Exchange Reaction Copyright © McGraw-Hill Education. Permission required for reproduction or display. (c) Exchange reaction Figure 2.12c ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Classes of Chemical Reactions 3 Reversible reactions – Can go in either direction under different circumstances – Symbolized with double-headed arrow – Example: An important reaction in respiratory, urinary, digestive physiology – Law of mass action—direction of reaction determined by relative abundance of substances on either side of equation More abundant substances serve as reactants – Reach equilibrium when ratio of products to reactants is stable ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Reaction Rates Reactions occur when molecules collide with enough force and correct orientation Reaction rates increase when… – the reactants are more concentrated – the temperature rises – a catalyst is present Enzyme catalysts bind to reactants and hold them in orientations that facilitate the reaction Catalysts are not changed by the reaction and can repeat the process frequently ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior Metabolism, Oxidation, and Reduction Metabolism—all chemical 1 reactions of the body Catabolism – Energy-releasing (exergonic) decomposition reactions Breaks covalent bonds Produces smaller molecules Anabolism – Energy-storing (endergonic) synthesis reactions Requires energy input Production of protein or fat ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior Metabolism, Oxidation, and Reduction Oxidation 2 – A chemical reaction in which a molecule gives up electrons and releases energy – Molecule oxidized in this process – Electron acceptor molecule is the oxidizing agent Oxygen is often involved as the electron acceptor Reduction – Any chemical reaction in which a molecule gains electrons and energy – Molecule is reduced when it accepts electrons – Molecule that donates electrons is the ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior Metabolism, Oxidation, and Reduction 3 (redox) reactions Oxidation-reduction – Oxidation of one molecule is always accompanied by reduction of another – Electrons are often transferred as hydrogen atoms ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  2.4 Organic Compounds Expected Learning Outcomes – Explain why carbon is especially well suited to serve as the structural foundation of many biological molecules. – Identify some common functional groups of organic molecules from their formulae. – Discuss the relevance of polymers to biology and explain how they are formed and broken by dehydration synthesis and hydrolysis. – Discuss the types and functions of carbohydrates, lipids, and proteins. – Explain how enzymes function. – Describe the structure, production, and function of ATP. – Identify other nucleotide types and their functions; and the principal types of nucleic acids. ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Carbon Compounds and Functional Groups 1 Organic chemistry—the study of compounds containing carbon Four categories of carbon compounds – Carbohydrates – Lipids – Proteins – Nucleic acids ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Carbon Compounds and Functional Groups Carbon has four valence2electrons – Binds with other atoms that can provide it with four more electrons to fill its valence shell Carbon atoms bind readily with each other to form carbon backbones – Form long chains, branched molecules, and rings – Form covalent bonds with hydrogen, oxygen, nitrogen, sulfur, and other elements Carbon backbones carry a variety of ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Carbon Compounds and Functional Groups 3 clusters of Functional groups—small atoms attached to carbon backbone Determine many of the properties of organic molecules Examples: hydroxyl, methyl, carboxyl, amino, phosphate ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Functional Groups of Organic Molecules Copyright © McGraw-Hill Education. Permission required for reproduction or display. Name Structur Occurs in and e Symbol Hydroxyl Sugars, alcohols Methyl Fats, oils, steroids, amino acids Carboxyl Amino acids, sugars, proteins Amino Amino acids, proteins Phospha Nucleic Figure te acids, ATP 2.13 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Monomers and Polymers 1 Macromolecules—very large organic molecules with high molecular weights Polymers—macromolecules made of a repetitive series of identical or similar subunits (monomers) – Starch is a polymer of about 3,000 glucose monomers Polymerization—joining monomers to form a polymer ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Monomers and Polymers 2 Dehydration synthesis (condensation) is how living cells form polymers – A hydroxyl (-OH) group is removed from one monomer, and a hydrogen (-H) from another Producing water as a by-product – Monomers covalently bind together to form a polymer with the removal of a water molecule Hydrolysis—digestion; the opposite of dehydration synthesis – A water molecule ionizes into –OH and -H – The covalent bond linking one monomer to the other is broken – The -OH is added to one monomer – The -H is added to the other – Splitting a polymer by the addition of a water molecule ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior Dehydration Synthesis and Hydrolysis Reactions Copyright © McGraw-Hill Education. Permission required for reproduction or display. (a) Dehydration synthesis (b) Hydrolysis Figure 2.14 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Carbohydrates 1 Hydrophilic organic molecule – Examples: sugars and starches General formula – , n = number of carbon atoms – Glucose, n = 6, so formula is – 2:1 ratio of hydrogen to oxygen Names of carbohydrates often built from the root “sacchar-” and the suffix “-ose” both meaning sugar, sweet ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Carbohydrates 2 Three important monosaccharides – Glucose, galactose, and fructose – Same molecular formula: All isomers of each other – Produced by digestion of complex carbohydrates Glucose is blood sugar ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  The Three Major Monosaccharides Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.15 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Carbohydrates 3 Disaccharide—sugar made of two monosaccharides Three important disaccharides – Sucrose—table sugar Glucose + fructose – Lactose—sugar in milk Glucose + galactose – Maltose—grain products Glucose + glucose ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  The Three Major Disaccharides Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.16 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Carbohydrates 4 Oligosaccharides—short chains of 3 or more monosaccharides (at least 10) Polysaccharides—long chains of monosaccharides (at least 50); three key examples: – Glycogen—energy storage in cells of liver, muscle, brain, uterus, vagina – Starch—energy storage in plants that is digestible by humans – Cellulose—structural molecule in plants that is important for human dietary fiber (but indigestible to us) ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Glycogen Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.17 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Carbohydrates 5 Carbohydrates are a quickly mobilized source of energy – All digested carbohydrates converted to glucose – Oxidized to make ATP Conjugated carbohydrate—covalently bound to lipid or protein moiety – Glycolipids External surface of cell membrane – Glycoproteins External surface of cell membrane Mucus of respiratory and digestive tracts – Proteoglycans—more carbohydrate than protein Gels that hold cells and tissues together Gelatinous filler in umbilical cord and eye Joint lubrication and cartilage texture ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Lipids 1 Lipids are hydrophobic organic molecules with a high ratio of hydrogen to oxygen Have more calories per gram than carbohydrates Five primary types in humans – Fatty acids – Triglycerides – Phospholipids – Eicosanoids – Steroids ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Lipids 2 Fatty acids – Chains of 4-24 carbon atoms with carboxyl group on one end and methyl group on the other – Saturated fatty acids have a lot of hydrogen – Unsaturated fatty acids contain some double bonds between carbons in chain (potential to add hydrogen) Polyunsaturated fatty acids have multiple double bonds between carbons in chain – Essential fatty acids must be obtained from food ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Lipids 3 Triglycerides (Neutral Fats) – Three fatty acids linked to glycerol – Each bond formed by dehydration synthesis – Broken down by hydrolysis Triglycerides at room temperature – When liquid, called oils Often polyunsaturated fats from plants – When solid, called fat Saturated fats from animals Primary function: energy storage – Also help with insulation and shock absorption (adipose tissue) ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Triglyceride (Fat) Synthesis 1 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Palmitic acid (saturated) Stearic acid (saturated) Linoleic acid (unsaturated) Figure 2.18a ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Triglyceride (Fat) Synthesis 2 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.18b ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior Trans Fats and Cardiovascular Health Trans-fatty acids – Two covalent single bonds angle in opposites (trans, “across from each other”) on each side of the double bond – Resist enzymatic breakdown in the human body, remain in circulation longer, deposits in the arteries; thus, raises the risk of heart disease Cis-fatty acids – Two covalent single bonds angle in the same direction adjacent to the double bond ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Trans- and Cis- Fatty Acids Copyright © McGraw-Hill Education. Permission required for reproduction or display. (a) A trans-fatty acid (elaidic acid) (b) A cis-fatty acid (oleic acid) Figure 2.19 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Lipids 4 Phospholipids—similar to neutral fats except one fatty acid is replaced by a phosphate group Structural foundation of cell membrane Amphipathic – Fatty acid “tails” are hydrophobic – Phosphate “head” is hydrophilic ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Lecithin, a Representative Phospholipid Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.20 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Lipids 5 Eicosanoids – 20-carbon compounds derived from arachidonic acid Hormone-like chemical signals between cells Includes prostaglandins – Role in inflammation, blood clotting, hormone action, labor contractions, blood vessel diameter Copyright © McGraw-Hill Education. Permission required for reproduction or display. ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Lipids 6 Steroid—a lipid with 17 carbon atoms in four rings Cholesterol—the “parent” steroid from which the other steroids are synthesized – Important for nervous system function and structural integrity of all cell membranes – 15% of our cholesterol comes from diet – 85% is internally synthesized (mostly in liver) Other steroids: cortisol, progesterone,estrogens, testosterone, and bile acids ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Cholesterol Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.22 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  “Good” and “Bad” Cholesterol There is only one kind of cholesterol – Does more good than harm “Good” and “bad” cholesterol refer to droplets of lipoprotein in the blood – Complexes of cholesterol, fat, phospholipid, and protein HDL (high-density lipoprotein): “good” cholesterol – Lower ratio of lipid to protein – May help to prevent cardiovascular disease LDL (low-density lipoprotein): “bad” cholesterol – High ratio of lipid to protein – Contributes to cardiovascular disease ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Proteins 1 Protein—a polymer of amino acids – Amino acid—central carbon with three attachments – Amino group (NH2), carboxyl group , and radical group (R group) – 20 amino acids used to make the proteins are identical except for the radical (R) group – Properties of amino acid determined by R group ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Amino Acids Copyright © McGraw-Hill Education. Permission required for Some nonpolarreproduction amino or display. Some polar amino acids acids Methionine Cystein e Amino acids differ only in the R group Figure 2.23a Tyrosin e Arginine ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Proteins 2 Peptide—any molecule composed of two or more amino acids joined by peptide bonds Peptide bond—joins the amino group of one amino acid to the carboxyl group of the next – Formed by dehydration synthesis Peptides named for the number of amino acids – Dipeptides have 2 – Tripeptides have 3 – Oligopeptides have fewer than 10 or 15 – Polypeptides have more than 15 – Proteins have more than 50 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Peptide Bond Formation Copyright © McGraw-Hill Education. Permission required for reproduction or display. Dehydration synthesis creates a peptide bond that joins the amino acid of one group to the carboxyl group of the next. ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Protein Structure 1 Conformation—unique, three- dimensional shape of protein crucial to function – Proteins can reversibly change conformation and thus function Important examples seen in muscle contraction, enzyme catalysis, membrane channel opening Denaturation – Extreme conformational change that destroys function Extreme heat or pH Example: when you cook an egg ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Protein Structure 2 Primary structure – Protein’s sequence of amino acids which is encoded in the genes Secondary structure – Coiled or folded shape held together by hydrogen bonds – Hydrogen bonds between slightly negative and slightly positive groups – Most common secondary structures are: Alpha helix—spring-like shape Beta helix—pleated, ribbon-like shape ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Protein Structure 3 Tertiary structure – Further bending and folding of proteins into globular and fibrous shapes due to hydrophobic-hydrophilic interactions and van der Waals forces Globular proteins—compact tertiary structure for proteins within cell membrane and proteins that move freely in body fluids Fibrous proteins—slender filaments suited for roles in muscle contraction and strengthening of skin and hair Quaternary structure – Associations of two or more polypeptide chains due to ionic bonds and hydrophobic-hydrophilic interactions – Occurs only in some proteins – Example: hemoglobin has four peptide chains ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Four Levels of Protein Structure Copyright © McGraw-Hill Education. Permission required for reproduction or display. Primary structure Sequence of amino acids joined by peptide bonds Secondary structure Alpha helix or beta sheet formed by hydrogen bonding Tertiary structure Folding and coiling due to interactions among R groups and between R groups and surrounding water Quaternary structure Association of two or more polypeptide chains with each other Figure 2.24 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Protein Structure 4 Conjugated proteins contain a non–amino acid moiety called a prosthetic group Hemoglobin contains four complex iron- containing rings called a heme moiety – see previous slide ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Protein Functions 1 Structure – Keratin—tough structural protein of hair, nails, skin surface – Collagen—contained in deeper layers of skin, bones, cartilage, and teeth Communication – Some hormones and other cell-to-cell signals are proteins Ligand—a molecule that reversibly binds to a protein – Receptors to which signal molecules bind are proteins Membrane transport – Channel proteins in cell membranes govern what passes – Carriers—transport solutes to other side of membrane Catalysis – Most enzymes are globular proteins ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Protein Functions 2 Recognition and protection – Glycoproteins are important for immune recognition – Antibodies are proteins Movement – Motor proteins—molecules with the ability to change shape repeatedly Cell adhesion – Proteins bind cells together Example: sperm to egg – Keeps tissues from falling apart ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Enzymes and Metabolism Enzymes—proteins that function as biological catalysts – Permit reactions to occur rapidly at body temperature Substrate—substance enzyme acts upon Naming convention – Named for substrate with -ase as the suffix Amylase enzyme digests starch (amylose) Enzymes lower activation energy— energy needed to get reaction started ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Effect of an Enzyme on Activation Energy Copyright © McGraw-Hill Education. Permission required for reproduction or display. (a) Reaction occurring without (b) Reaction occurring with a catalyst a catalyst Figure 2.26 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Enzyme Structure and Action 1 Enzyme action – Substrate approaches enzyme’s active site – Molecules bind together forming enzyme– substrate complex Enzyme–substrate specificity—lock and key – Enzyme releases reaction products – Enzyme unchanged and can repeat process ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Enzyme Structure and Action 2 Enzyme action example of sucrose hydrolysis – Sucrose approaches sucrase’s active site – Molecules bind together forming enzyme–substrate complex – Sucrase breaks bonds between sugar subunits and adds and – Enzyme unchanged and can repeat process ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  The Three Steps of an Enzymatic Reaction Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Enzyme Structure and Action 3 Reusability of enzymes – Enzymes are not consumed by the reactions Astonishing speed – One enzyme molecule can consume millions of substrate molecules per minute Temperature, pH and other factors can change enzyme shape and function – Can alter ability of enzyme to bind to substrate – Enzymes vary in optimum pH Salivary amylase works best at pH 7.0 Pepsin in stomach works best at pH 2.0 – Temperature optimum for human enzymes—near body temperature (37°C) ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Cofactors Cofactors – About two-thirds of human enzymes require a nonprotein cofactor – Some are inorganic (iron, copper, zinc, magnesium, and calcium ions) – Some bind to enzyme and induce a change in its shape, which activates the active site – Essential to function – Coenzymes—organic cofactors derived from water- soluble vitamins (niacin, riboflavin) Accept electrons from an enzyme in one metabolic pathway and transfer them to an enzyme in another For example, ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Action of a Coenzyme Copyright © McGraw-Hill Education. Permission required for reproduction or display. transports electrons from one metabolic pathway to another ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Metabolic Pathways Chain of reactions, with each step usually catalyzed by a different enzyme αγ β ABCD A is the initial reactant, B and C are intermediates, and D is the end product Regulation of metabolic pathways – Cells can turn on or off pathways when end products are needed or unneeded ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  ATP, Other Nucleotides, and Nucleic Acids Three components of nucleotides – Nitrogenous base (single or double carbon– nitrogen ring) – Sugar (monosaccharide) – One or more phosphate groups Adensosine Triphosphate (ATP)—best- known nucleotide – Adenine (nitrogenous base) – Ribose (sugar) – ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  ATP and cAMP Copyright © McGraw-Hill Education. Permission required for reproduction or display. (a) Adenosine triphosphate (b) Cyclic adenosine (ATP) monophosphate (cAMP) ATP contains adenine, ribose, and three phosphate groups Figure 2.29 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Adenosine Triphosphate 1 ATP is body’s most important energy- transfer molecule Stores energy gained from exergonic reactions Releases it within seconds for physiological work Holds energy in covalent bonds – Second and third phosphate groups have high energy bonds (~) – Most energy transfers to and from ATP involve adding or removing the third phosphate ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Adenosine Triphosphate 2 Hydrolysis of ATP is catalyzed by adenosine triphosphatases (ATPases) – Breaks the third high-energy phosphate bond – Separates ATP into Phosphorylation – Addition of free phosphate group to a molecule – Carried out by enzymes called kinases ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Source and Uses of ATP Copyright © McGraw-Hill Education. Permission required for reproduction or display. Figure 2.30 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  ATP Production Copyright © McGraw-Hill Education. Permission required for reproduction or display. Glycolys is Glycolysis: splitting glucose Stages of into two glucose pyruvates oxidation Anaerobi If ATP demand c and ATP fermenta outpaces oxygen tion Uses supply pyruvate synthesis no oxygen anaerobically ferments to Aerobic lactate. respirati on If enough Requires oxygen oxygen present aerobic respiration occurs in mitochondria Figure 2.31 ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Other Nucleotides Guanosine triphosphate (GTP) – Another nucleotide involved in energy transfer Cyclic adenosine monophosphate (cAMP) – Formed by removal of second and third phosphate groups from ATP – Formation triggered by hormone binding to cell surface – cAMP becomes “second messenger” within cell ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior  Nucleic Acids Polymers of nucleotides DNA (deoxyribonucleic acid) – Contains millions of nucleotides – Constitutes genes Instructions for synthesizing proteins RNA (ribonucleic acid)—three types – Messenger RNA, ribosomal RNA, transfer RNA – 70 to 10,000 nucleotides long – Carries out genetic instruction for synthesizing proteins – Assembles amino acids in right order to ©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior