Announcements ●GE Survey-available on Blackboard ●Tutoring Center SCI I, 407 M 12-3, 5:30-6:30; W 8-9, 5:30-6:30, Th 8-12, 6-7; F 8-9 ●MasteringBiology Assignment

Review ●Process of Science ●Chemistry of Life atoms, elements, chemical bonding ●Properties of Water

Carbon and Organic Chemistry – Carbon is a versatile atom. – Carbon forms large, complex, and diverse molecules necessary for life’s functions. – Organic compounds are carbon-based molecules. Structural formula Ball-and-stick model Space-filling model

– Larger hydrocarbons form fuels for engines. – Hydrocarbons of fat molecules fuel our bodies. Hydrocarbons

Variations in Carbon skeletons Carbon skeletons vary in length Carbon skeletons may be unbranched or branched Carbon skeletons may have double bonds, which can vary in location Carbon skeletons may be arranged in rings Carbon and Organic Chemistry

The unique properties of an organic compound depend not only on its carbon skeleton but also on the atoms attached to the skeleton –These atoms are called functional groups –Some common functional groups include: Hydroxyl groupCarbonyl groupAmino groupCarboxyl group Found in alcohols and sugars Found in sugars Found in amino acids and urea in urine (from protein breakdown) Found in amino acids, fatty acids, and some vitamins Carbon and Organic Chemistry

Macromolecules – On a molecular scale, many of life’s molecules are gigantic, earning the name macromolecules. – Three categories of macromolecules are Carbohydrates Proteins Nucleic acids

*most macromolecules are polymers polymer monomer The making and breaking of polymers: Dehydration reaction:Hydrolysis: Macromolecules

Carbohydrates include Carbohydrates –Small sugar molecules in soft drinks Monosaccharides & Disaccharides –Long starch molecules in pasta and potatoes Polysaccharides

Monosaccharides are simple sugars Monosaccharides –Glucose, found in sports drinks –Fructose, found in fruit Honey contains both glucose and fructose Glucose Fructose Isomers

In aqueous solutions, monosaccharides form rings (b) Abbreviated ring structure Monosaccharides

A disaccharide is a double sugar Disaccharides Disaccharides are joined by the process of dehydration synthesis Glucose Maltose

The most common disaccharide is sucrose, common table sugar –It consists of a glucose linked to a fructose –Sucrose is extracted from sugar cane and the roots of sugar beets Disaccharides

Polysaccharides (a) Starch Starch granules in potato tuber cells Glucose monomer (b) Glycogen Glycogen Granules In muscle tissue (c) Cellulose Cellulose molecules Cellulose fibril in a plant cell wall –They are long chains of sugar units –They are polymers of monosaccharides

Most animals cannot derive nutrition from fiber –How do grazing animals survive on a diet of cellulose? Polysaccharides

Proteins Proteins perform most of the tasks the body needs to function –They are the most elaborate of life’s molecules MAJOR TYPES OF PROTEINS Structural ProteinsStorage Proteins Contractile ProteinsTransport ProteinsEnzymes

All proteins are constructed from a common set of 20 kinds of amino acids The Monomers: Amino Acids Amino group Carboxyl group Side group

Carboxyl group Amino group Side group Side group Amino acid Dehydration synthesis Side group Side group Peptide bond Cells link amino acids together by dehydration synthesis Proteins as Polymers –The resulting bond between them is called a peptide bond

Primary structure –The specific sequence of amino acids in a protein Amino acid –The arrangement of amino acids makes each protein different Protein Structure

A slight change in the primary structure of a protein affects its ability to function –The substitution of one amino acid for another in hemoglobin causes sickle-cell disease (a) Normal red blood cellNormal hemoglobin (b) Sickled red blood cellSickle-cell hemoglobin Protein Structure

Proteins have four levels of structure Hydrogen bond Pleated sheet Amino acid (a) Primary structure Hydrogen bond Alpha helix (b) Secondary structure Polypeptide (single subunit) (c) Tertiary structure Complete protein, with four polypeptide subunits (d) Quaternary structure Protein Structure

Gene DNA RNA Protein Amino acid Nucleic acids Nucleic Acids ● Include DNA and RNA Information storage molecules They provide the directions for building proteins

Phosphate group Nitrogenous base  A, G, C, or U  Uracil  U  Sugar  ribose  Nitrogenous base (A,G,C, or T) Phosphate group Thymine (T) Sugar (deoxyribose) Phosphate Base Sugar ●Nucleic acids are polymers of nucleotides –DNA, deoxyribonucleic acid –RNA, ribonucleic acid Nucleic Acids

●Each DNA nucleotide has one of the following bases: Adenine (A) Guanine (G) Thymine (T) Cytosine (C) Adenine  A  Guanine  G  Thymine  T  Cytosine  C 

Nucleic Acids Sugar-phosphate backbone Nucleotide Base pair Hydrogen bond Bases  a  DNA strand  polynucleotide   b  Double helix  two polynucleotide strands  ●Nucleic Acid Structure

●Lipids are: Neither macromolecules nor polymers Hydrophobic, unable to mix with water Lipids Oil (hydrophobic) Vinegar (hydrophilic) Figure 3.10

●FATS ● Dietary fat consists largely of the molecule triglyceride Lipids –A combination of glycerol and three fatty acids Fatty acid Glycerol (a) A dehydration reaction linking a fatty acid to glycerol (b) A fat molecule with a glycerol “head” and three energy-rich hydrocarbon fatty acid “tails”

●Unsaturated fatty acids Lipids (Fats) –Have less than the maximum number of hydrogens bonded to the carbons ●Saturated fatty acids –Have the maximum number of hydrogens bonded to the carbons

Lipids (Fats) Saturated Fats TYPES OF FATS Unsaturated Fats Margarine Plant oils Trans fats Omega-3 fats INGREDIENTS: SOYBEAN OIL, FULLY HYDROGENATED COTTONSEED OIL, PARTIALLY HYDROGENATED COTTONSEED OIL AND SOYBEAN OILS, MONO AND DIGLYCERIDES, TBHO AND CITRIC ACID ANTIOXIDANTS

Cholesterol TestosteroneA type of estrogen ●STEROIDS Steroids are very different from fats in structure and function. Lipids

Visual Summary 3.2 Biological Molecules