All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education. Chapter 2 Lecture Outline See separate PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes.
Scoping Out the Chapter (1 of 6) Atomic Structure: All matter is composed of atoms, and the number of protons, neutrons, and electrons ultimately determines the characteristics of each element. 2-2
Scoping Out the Chapter (2 of 6) Chemical Properties: Atoms react with one another, making or breaking chemical bonds, to create complex molecules and compounds. 2-3
Scoping Out the Chapter (3 of 6) Carbohydrates: Simple carbohydrates are used as a source of energy, while more complex carbohydrates provide structure to the walls of plants, algae, and bacterial cells. 2-4
Scoping Out the Chapter (4 of 6) Lipids: An important energy source because of their high energy to weight ratio, lipids serve as a major component of cell membranes. 2-5
Scoping Out the Chapter (5 of 6) Proteins: The three-dimensional shape of proteins is essential to their function, whether as structural parts of the cell or as enzymes, catalyzing biochemical reactions. 2-6
Scoping Out the Chapter (6 of 6) Nucleic acids: The genetic information of cells and viruses is carried in the nucleic acids DNA and RNA. 2-7
Atoms, Bonds, and Molecules (1 of 2) Matter - all materials that occupy space and have mass. Matter is composed of atoms Atom - simplest form of matter not divisible into simpler substances Protons: (+) subatomic particles Neutrons: neutral subatomic particles Electrons: (-) subatomic particles 2-8
Atoms, Bonds, and Molecules (2 of 2) 2-9
Different Types of Atoms (1 of 2) All atoms share the same fundamental structure Element - pure substances with a characteristic number of protons, neutrons, and electrons and predictable chemical behaviors The figure of Different Types of Atoms. (a1) Hydrogen 2-10
Different Types of Atoms (2 of 2) The figure of Different Types of Atoms continues on this slide. (a2) Carbon 2-11
The Major Elements of Life (1 of 3) TABLE 2.1 Chemical Characteristics of Major Elements of Life Element Calcium Carbon Carbon. Chlorine Cobalt Copper Hydrogen Hydrogen. Iodine Atomic Symbol * Ca C C 14 Cl Co Cu H H 3 I Atomic Number 20 6 6 17 27 29 1 1 53 Atomic Mass * * 40.08 12.01 14.0 35.45 58.93 63.54 1.00 3.01 126.9 Ionized Forms ( see section 2.3) Ca CO Cl H I + Co Cu 2+ 2 3 2+ +,Co,Cu 3+ 2+ 2-12
The Major Elements of Life (2 of 3) The TABLE 2.1 continues on this slide. Element. Iodine Iron Magnesium Manganese Nitrogen Oxygen Phosphorus Phosphorus. Potassium Sodium Sulfur Zinc Atomic * Symbol I 131 Fe Mg Mn N O P P 32 K Na S Zn Atomic Number 53 26 12 25 7 8 15 15 19 11 16 30 Atomic ** Mass 131.0 55.84 24.30 54.93 14.0 15.99 31.97 32 39.10 22.99 32.06 65.38 Ionized Forms ( see section 2.3) Fe Mg Mn NO PO K + Na Zn 2+ 2+ 2+ 3 3 4 + SO 2 4 2+,Fe 3+,Mn 3+ (nitrate (phosphate) (sulfate) 2-13
The Major Elements of Life (3 of 3) The TABLE 2.1 continues on this slide. * Based on the Latin name of the element. The first letter is always capitalized; if there is a second letter, it is always lowercased. ** The atomic mass or weight is equal to the average mass number for the isotopes of that element.. An isotope of the element. 2-14
Characteristics of Elements (1 of 2) Atomic number number of protons Mass number number of protons and neutrons Isotopes variant forms of the same element that differ in the number of neutrons Atomic weight average mass numbers of all isotopic forms Electron orbitals volumes of space surrounding the atomic nucleus where electrons are likely to be found 2-15
Characteristics of Elements (2 of 2) 2-16
Biologically Important Atoms 2-17
Concept Check: (1) If two atoms have the same number of protons and electrons but different numbers of neutrons, they would be A. Different elements B. Isotopes of the same element C. Ions of the same element D. Orbitals of the same element 2-18
Concept Check: (2) If two atoms have the same number of protons and electrons but different numbers of neutrons, they would be A. Different elements B. Isotopes of the same element C. Ions of the same element D. Orbitals of the same element Answer: B 2-19
Bonds and Molecules (1 of 2) Molecule - a chemical substance that results from the combination of two or more atoms Compounds - molecules that are combinations of two or more different elements 2-20
Bonds and Molecules (2 of 2) Formula/Mass weight - sum of all of the atomic masses of the atoms a molecule contains Chemical bonds - when 2 or more atoms share, donate, or accept electrons to form molecules and compounds Three types: 1. Covalent bonds 2. Ionic bonds, and 3. Hydrogen bonds 2-21
Types of Chemical Bonds: Covalent Bonds (1 of 3) 1. Covalent bonds electrons are shared among atoms Polar covalent bonds unequal sharing Nonpolar covalent bonds equal sharing 2-22
Types of Chemical Bonds: Covalent a) Covalent Bonds Bonds (2 of 3) 2-23
Types of Chemical Bonds: Covalent Bonds (3 of 3) 2-24
Polarity 2-25
Types of Chemical Bonds: Ionic 1. Covalent bonds Bonds (1 of 4) 2. Ionic Bonds one or more electrons from one atom are removed and attached to another atom, forming positively charged cations and negatively charged anions 2-26
Types of Chemical Bonds: Ionic b) Ionic Bond Bonds (2 of 4) 2-27
Types of Chemical Bonds: Ionic Bonds (3 of 4) Kathy Park Talaro 2-28
Types of Chemical Bonds: Ionic Bonds (4 of 4) 2-29
Types of Chemical Bonds: Hydrogen 1. Covalent bonds 2. Ionic Bond Bonds (1 of 2) 3. Hydrogen bonds weak bonds between hydrogen and other atoms 2-30
Types of Chemical Bonds: Hydrogen c) Hydrogen Bond Bonds (2 of 2) 2-31
Concept Check: (3) Molecules where atoms share electrons contain A. Covalent Bonds B. Ionic Bonds C. Hydrogen Bonds 2-32
Concept Check: (4) Molecules where atoms share electrons contain A. Covalent Bonds B. Ionic Bonds C. Hydrogen Bonds Answer: A 2-33
Oxidation-Reduction Reactions Energy exchange in cells is a result of the movement of electrons from one molecule to another. Oxidation the loss of electrons Reduction the gaining of electrons Redox reactions 2-34
Chemical Shorthand (1 of 2) Reactants - molecules starting a reaction Products - substances left by a reaction Synthesis reaction - the reactants bond together in a manner that produces an entirely new molecule S + O 2 SO 2 Decomposition reaction - the bonds on a single reactant molecule are broken to release two or more products 2H + 2O2 2H2O O2 2-35
Chemical Shorthand (2 of 2) Exchange reaction - the reactants trade portions between each other and release products that are combinations of the two HCl + NaOH NaCl + H2O 2-36
Solutions Solution a mixture of one or more substances called solutes, dispersed in a dissolving medium called a solvent Solutes Na Solvent H O 2 + & Cl - 2-37
Aqueous Solutions Hydrophilic molecules - dissolve in water Hydrophobic molecules - repel water Amphipathic molecules - have both hydrophilic and hydrophobic properties 2-38
Acidity, Alkalinity, and the ph Scale Ionization of H2O releases hydrogen ions [H+] and hydroxyl ions [OH-] ph scale ranges from 0 to 14, expresses the concentration of H+ ions ph is the negative logarithm of the concentration of H+ 2-39
ph and Ion Concentration TABLE 2.2 Hydrogen Ion and Hydrogen Ion Concentrations at a Given ph 0.1 Moles L of Hydrogen Ions 1.0 0.01 0.001 0.0001 0.00001 0.000001 0.0000001 0.00000001 0.000000001 0.0000000001 0.00000000001 0.000000000001 0.0000000000001 0.00000000000001 Logarithm 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 ph 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Moles 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 L of OH 2-40
Concept Check: (5) If solution A has a ph of 2 and solution B has a ph of 4, which of the following is true? A. Solution A has 2 times more H+ ions than solution B B. Solution B has 2 times more H+ ions than solution A C. Solution A has 10 times more H+ ions than solution B D. Solution B has 10 times more H+ ions than solution A E. Solution A has 100 times more H+ ions than solution B 2-41
Concept Check: (6) If solution A has a ph of 2 and solution B has a ph of 4, which of the following is true? A. Solution A has 2 times more H+ ions than solution B B. Solution B has 2 times more H+ ions than solution A C. Solution A has 10 times more H+ ions than solution B D. Solution B has 10 times more H+ ions than solution A E. Solution A has 100 times more H+ ions than solution B Answer: E 2-42
The Chemistry of Carbon and Organic Compounds Organic chemicals compounds containing carbon bonded to hydrogens Carbon is the fundamental element of life Contains 4 atoms in its outer orbital Can form single, double, or triple covalent bonds Can form linear, branched, or ringed molecules 2-43
The Versatility of Bonding in Carbon 2-44
Functional Groups of Organic Compounds (1 of 5) Accessory molecules that bind to organic compounds Confer unique reactive properties on the whole molecule TABLE 2.3 Representative Functional Groups and Organic Compounds That Contain Them Formula of Functional Group: Name: Hydroxyl Can Be Found In: Alcohols, carbohydrates 2-45
Functional Groups of Organic Compounds (2 of 5) The TABLE 2.3 continues on this slide. Formula of Functional Group: Name: Carboxyl Can Be Found In: Fatty acids, proteins organic acids Formula of Functional Group: Name: Amino Can Be Found In: Proteins, nucleic acids 2-46
Functional Groups of Organic Compounds (3 of 5) The TABLE 2.3 continues on this slide. Formula of Functional Group: Name: Ester Can Be Found In: Lipids Formula of Functional Group: Name: Sulfhydryl Can Be Found In: Cysteine (amino acid), proteins 2-47
Functional Groups of Organic Compounds (4 of 5) The TABLE 2.3 continues on this slide. Formula of Functional Group: Name: Carbonyl, terminal end Can Be Found In: Aldehydes, polysaccharides Formula of Functional Group: Name: Carbonyl, internal Can Be Found In: Ketones, polysaccharides 2-48
Functional Groups of Organic Compounds (5 of 5) The TABLE 2.3 continues on this slide. Formula of Functional Group: Name: Phosphate Can Be Found In: DNA, RNA, ATP * The R designation on a molecule is shorthand for remainder, and its placement in a formula indicates that what is attached at that site varies from one compound to another. 2-49
Macromolecules Biochemicals are organic compounds produced by living things Macromolecules: large compounds assembled from smaller subunits Monomer: a repeating subunit Polymer: a chain of monomers 4 Biological Macromolecules: Carbohydrates, Lipids, Proteins, Nucleic Acids 2-50
Biological Macromolecules (1 of 2) TABLE 2.4 Macromolecules and Their Functions Macromolecule Carbohydrates Monosaccharides Disaccharides Description/Base Structure 3- to 7-carbon sugars Two monosaccharides Examples/Notes Glucose, fructose / Sugars involved in metabolic reactions; building block of disaccharides and polysaccharides Maltose (malt sugar) / Composed of two glucoses; an important breakdown product of starch Lactose (milk sugar) / Composed of glucose and galactose Sucrose (table sugar) / Composed of glucose and fructose Polysaccharides Chains of monosaccharides Starch, cellulose, glycogen / Cell wall, food storage Lipids Triglycerides Phospholipids Fatty acids + glycerol Fatty acids + glycerol + phosphate Fats, oils / Major component of cell membranes; storage Membranes Membranes Waxes Fatty acids, alcohols Mycolic acid / Cell wall of mycobacteria Steroids Ringed structure Cholesterol, ergosterol / Membranes of eukaryotes and some bacteria 2-51
Biological Macromolecules (2 of 2) The TABLE 2.4 continues on this slide. Macromolecule Description/Base Structure Examples/Notes Proteins Polypeptides Nucleic acids Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA) Adenosine triphosphate (ATP) Amino acids in a chain bound by peptide bonds Nucleotides, composed of pentose sugar + phosphate + nitrogenous base Contains deoxyribose sugar and thymine, not uracil Contains ribose sugar and uracil, not thymine Contains adenine, ribose sugar, and 3 phosphate groups Enzymes; part of cell membrane, cell wall, ribosomes, antibodies / Metabolic reactions; structural components Purines: adenine, guanine; Pyrimidines: cytosine, thymine, uracil Chromosomes; genetic material of viruses / Inheritance Ribosomes; mrna, trna / Expression of genetic traits A high-energy compound that gives off energy to power reactions in cells 2-52
1. Carbohydrates: Basic Structure General formula: (CH2O)n Basic structure: Backbone of carbon Polyhydroxy aldehyde or ketone 2-53
1. Carbohydrates: Common Configurations Common carbohydrate configurations: Monosaccharide: polyhydroxy aldehyde or ketone with 3-7 carbons Disaccharide: two monosaccharides Polysaccharide: five or more monosaccharides 2-54
1. Carbohydrates: Biosynthesis (1 of 2) Glycosidic bonds link subunits of disaccharides and polysaccharides Dehydration synthesis: loss of water in a polymerization reaction 2-55
1. Carbohydrates: Biosynthesis (2 of 2) 2-56
1. Carbohydrates: Function Functions polysaccharides provide cell structure, adhesion, and metabolism 2-57
2. Lipids Long or complex, hydrophobic, C H chains attached to a glycerol molecule Created by dehydration synthesis Classification: Triglycerides, phospholipids, steroids, and waxes. a) Triglyceride synthesis 2-58
2. Lipids: Triglycerides (1 of 2) 3 fatty acids bound to glycerol Functions: Triglycerides (saturated or unsaturated) energy storage Phospholipid major cell membrane component Steroids found in cell membrane and animal hormones 2-59
2. Lipids: Triglycerides (2 of 2) b) Examples of fatty acid 1. Palmitic acis, a saturated fatty acid 2. Linolenic acid, an unsaturated fatty acid that is polysaturated because it has 3 double bonds 2-60
2. Lipids: Phospholipids Glycerol with 2 fatty acids and a phosphate group Bilayers of phospholipids form membranes 2-61
2. Lipids: Steroids Cholesterol is inserted into the phospholipid bilayer It reinforces the membrane 2-62
Concept Check: (7) Triglycerides that have double bonds in their fatty acids are best described as A. Saturated B. Unsaturated C. Phospholipids D. Cholesterol 2-63
Concept Check: (8) Triglycerides that have double bonds in their fatty acids are best described as A. Saturated B. Unsaturated C. Phospholipids D. Cholesterol Answer: B 2-64
3. Proteins (1 of 7) Predominant molecules in cells Monomer amino acids 20 Polymer peptide, polypeptide, protein The figure of Proteins. Amino Acid: Alanine Structural Formula: Amino Acid: Valine Structural Formula: 2-65
3. Proteins (2 of 7) The figure of Proteins continues on this slide. Amino Acid: Cysteine Structural Formula: Amino Acid: Phenylalanine Structural Formula: 2-66
3. Proteins (3 of 7) The figure of Proteins continues on this slide. Amino Acid: Tyrosine Structural Formula: 2-67
3. Proteins (4 of 7) Amino acids are attached through peptide bonds to form proteins 2-68
3. Proteins (5 of 7) Fold into very specific 3-D shapes Functions support, enzymes, transport, defense, movement The figure of Structural Level of Protein. 1. The primary structure is a series of amino acids bound in a chain. Amino acids display small charged functional groups (red symbols). 2. The secondary structure develops when CO - and NH - groups on adjacent amino acids form hydrogen bonds. This action folds the chain into local configurations called the α helix and β- pleated sheet. Most proteins have both types of secondary structures. 2-69
3. Proteins (6 of 7) The figure of Structural Level of Protein continues on this slide. 3. The tertiary structure forms when portions of the secondary structure further interact by forming covalent disulfide bonds and additional interactions. From this emerges a stable threedimensional molecule. Depending on the protein, this may be the final functional state. 4. The quaternary structure exists only in proteins that consist of more than one polypeptide chain. The structure of the Shiga toxin, produced by Shigella bacteria, is a combination of separate polypeptides (shown in different colors). 2-70
3. Proteins (7 of 7) The figure of Structural Level of Protein continues on this slide. 2-71
4. Nucleic Acids (1 of 4) DNA and RNA Nucleotide monomer DNA deoxyribonucleic acid A,T,C,G nitrogen bases Double helix Function hereditary material RNA ribonucleic acid A,U,C,G nitrogen bases Function organize protein synthesis 2-72
4. Nucleic Acids (2 of 4) a) A nucleotide, composed of a phosphate, a pentose sugar, and a nitrogenous base (either A, T, C, G, or U) is the monomer of both DNA and RNA. 2-73
4. Nucleic Acids (3 of 4) b) In DNA, the polymer is composed of alternating deoxyribose (D) and phosphate (P) with nitrogenous bases (A,T,C,G) attached to the deoxyribose. DNA almost always exists in pairs of strands, oriented so that the bases are paired across the central axis of the molecule. 2-74
4. Nucleic Acids (4 of 4) c) In RNA, the polymer is composed of alternating ribose (R) and phosphate (P) attached to nitrogenous bases (A,U,C,G), but it is usually a single strand. 2-75
4. Nucleic Acids: Nucleotide Components (1 of 3) DNA Nucleotides: Deoxyribose C, G, A or T RNA Nucleotides: Ribose C, G, A or U 2-76
4. Nucleic Acids: Nucleotide Components (2 of 3) a) Pentose sugars b) Purine bases 2-77
4. Nucleic Acids: Nucleotide Components (3 of 3) c) Pyrimidine bases 2-78
4. Nucleic Acids: Double Helix of DNA DNA is formed by two very long polynucleotide strands linked along their length by hydrogen bonds between the nitrogenous bases 2-79
4. Nucleic Acids: DNA Replication Each strand is copied (1 of 2) Replication is guided by base pairing End result is two separate double strands Allows making new DNA molecules to pass on the genetic message 2-80
4. Nucleic Acids: DNA Replication (2 of 2) 2-81
ATP: The Energy Molecule of Cells Adenosine triphosphate Nucleotide - adenine, ribose, three phosphates Function - transfer and storage of energy 2-82
Concept Check: (9) Which of the following is TRUE about RNA? A. It is a double stranded molecule B. It contains the sugar deoxyribose C. It contains the nitrogenous base Uracil D. It holds the genetic information E. All of the above are true 2-83
Concept Check: (10) Which of the following is TRUE about RNA? A. It is a double stranded molecule B. It contains the sugar deoxyribose C. It contains the nitrogenous base Uracil D. It holds the genetic information E. All of the above are true Answer: C 2-84
End of Presentation All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education. 3-85 2-85