PowerPoint Lecture Outlines to accompany Hole s Human Anatomy and Physiology Tenth Edition Shier w Butler w Lewis Chapter 2 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 2-1
Chapter 2 Chemical Basis of Life Why study chemistry in an Anatomy and Physiology class? - body functions depend on cellular functions - cellular functions result from chemical changes - biochemistry helps to explain physiological processes, and develop new drugs and methods for treating diseases 2-2
Structure of Matter Matter anything that takes up space and has weight; composed of elements Elements composed of chemically identical atoms bulk elements required by the body in large amounts [C,O,H,N,Ca,P,K,S,Cl,Na,Mg] 99.9% trace elements required by the body in small amounts [Co,Cu,F,I,Fe,Mn,Zn] under.1% Atoms smallest particle of an element 2-3
Atomic Structure Atoms - composed of subatomic particles: protons carry a positive charge neutrons carry no electrical charge electrons carry a negative charge Nucleus central part of atom composed of protons and neutrons electrons move around the nucleus 2-4
Atomic Number and Atomic Number number of protons in the nucleus of one atom each element has a unique atomic number equals the number of electrons in the atom Atomic Weight Atomic Weight the number of protons plus the number of neutrons in one atom electrons do not contribute to the weight of the atom 2-5
Isotopes Isotopes atoms with the same atomic numbers but with different atomic weights atoms with the same number of protons and electrons but a different number of neutrons oxygen often forms isotopes (O 16, O 17, O 18 ) unstable isotopes are radioactive; they emit subatomic particles 2-6
Molecules and Compounds Molecules particle formed when two or more atoms chemically combine Compound particle formed when two or more atoms of different elements chemically combine Molecular formulas depict the elements present and the number of each atom present in the molecule H 2 C 6 H 12 O 6 H 2 O 2-7
Electrons found in regions of space called electron shells (energy shells) each shell can hold a limited number of electrons for atoms with atomic numbers of 18 or less, the following rules apply: the first shell can hold up to 2 electrons the second shell can hold up to 8 electrons the third shell can hold up to 8 electrons lower shells are filled first if the outermost shell is full, the atom is stable 2-8
Ions Ion an atom that has gained or lost an electron(s) an electrically charged atom atoms form ions to become stable Cation a positively charged ion formed when an atom loses an electron(s) Anion a negatively charged ion formed when an atom gains an electron(s) 2-9
Ionic Bond Ionic Bond an attraction between a cation and an anion formed when electrons are transferred from one atom to another atom 2-10
Covalent Bond Formed when atoms share electrons Hydrogen atoms form single bonds Oxygen atoms form two bonds Nitrogen atoms form three bonds Carbon atoms form four bonds H H O = O N N O = C = O 2-11
Structural Formula Structural formulas show how atoms bond and are arranged in various molecules 2-12
Polar Molecules Polar Molecule molecule with a slightly negative end and a slightly positive end results when electrons are not shared equally in covalent bonds water is an important polar molecule 2-13
Hydrogen Bonds Hydrogen Bond a weak attraction between the positive end of one polar molecule and the negative end of another polar molecule formed between water molecules important for protein and nucleic acid structure 2-14
Chemical Reactions Chemical reactions occur when chemical bonds form or break among atoms, ions, or molecules Reactants are substances being changed by the chemical reaction Products are substances formed at the end of the chemical reaction NaCl Na + + Cl - Reactant Products 2-15
Types of Chemical Reactions Synthesis Reaction chemical bonds are formed A + B AB Decomposition Reaction chemical bonds are broken AB A + B Exchange Reaction chemical bonds are broken and formed AB + CD AD + CB Reversible Reaction the products can change back to the reactants A + B n AB 2-16
Acids, Bases, and Salts Electrolytes substances that release ions in water NaCl à Na + + Cl - Acids electrolytes that release hydrogen ions in water HCl à H + + Cl - Bases substances that release ions that can combine with hydrogen ions NaOH à Na + + OH - Salts electrolytes formed by the reaction between an acid and a base HCl + NaOH à H 2 O + NaCl 2-17
Acid and Base Concentrations ph scale - indicates the concentration of hydrogen ions in solution Neutral ph 7; indicates equal concentrations of H + and OH - Acidic ph less than 7; indicates a greater concentration of H + Basic or alkaline ph greater than 7; indicates a greater concentration of OH - 2-18
Organic Versus Inorganic Organic molecules contain C and H usually larger than inorganic molecules dissolve in water and organic liquids carbohydrates, proteins, lipids, and nucleic acids Inorganic molecules generally do not contain C usually smaller than organic molecules usually dissolve in water or react with water to release ions water, oxygen, carbon dioxide, and inorganic salts 2-19
Inorganic Substances Water most abundant compound in living material two-thirds of the weight of an adult human major component of all body fluids medium for most metabolic reactions important role in transporting chemicals in the body can absorb and transport heat Oxygen (O 2 ) used by organelles to release energy from nutrients necessary for survival 2-20
Inorganic Substances Carbon dioxide (CO 2 ) waste product released during metabolic reactions must be removed from the body Inorganic salts abundant in body fluids sources of necessary ions (Na +, Cl -, K +, Ca 2+, etc.) play important roles in metabolic processes 2-21
Organic Substances Carbohydrates provide energy to cells supply materials to build cell structures water-soluble contain C, H, and O ratio of H to O close to 2:1 (C 6 H 12 O 6 ) monosaccharides glucose, fructose disaccharides sucrose, lactose polysaccharides glycogen, cellulose 2-22
Organic Substances Carbohydrates The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. 2-23
Organic Substances Lipids soluble in organic solvents fats (triglycerides) used primarily for energy contain C, H, and O but less O than carbohydrates (C 57 H 110 O 6 ) building blocks are 1 glycerol and 3 fatty acids per molecule saturated and unsaturated 2-24
phospholipids Organic Substances Lipids building blocks are 1 glycerol, 2 fatty acids, and 1 phosphate per molecule hydrophilic and hydrophobic major component of cell membranes 2-25
Organic Substances Lipids steroids connected rings of carbon component of cell membrane used to synthesize hormones cholesterol 2-26
Organic Substances Proteins structural material energy source hormones receptors enzymes antibodies building blocks are amino acids amino acids held together with peptide bonds 2-27
Organic Substances Proteins Four Levels of Structure 2-28
Organic Substances Nucleic Acids constitute genes play role in protein synthesis building blocks are nucleotides DNA (deoxyribonucleic acid) double polynucleotide RNA (ribonucleic acid) single polynucleotide 2-29
Organic Substances Nucleic Acids 2-30
Clinical Applications Radioactive Isotopes Reveal Physiology injected into the body different types taken up by different organs can be detected in the body using a scintillation counter can be used to destroy specific tissues commonly used iodine-131 for thyroid function thallium-201 for heart function gallium-67 and cobalt-60 for cancer others used to assess kidney functions, measure hormone levels and bone density changes 2-31