PowerPoint ® Lecture Slides prepared by Janice Meeking, Mount Royal College C H A P T E R Copyright © 2010 Pearson Education, Inc. 2 Chemistry Comes Alive: Part B

Copyright © 2010 Pearson Education, Inc. Classes of Compounds Inorganic compounds Do not contain carbon Ex. water, salts, and many acids and bases Organic compounds Contain carbon, usually large, and are covalently bonded Ex. carbohydrates, fats, proteins, and nucleic acids

Copyright © 2010 Pearson Education, Inc. Water Most important inorganic compound in living organisms because of its properties.

Copyright © 2010 Pearson Education, Inc. Properties of Water High heat capacity Absorbs and releases heat with little temperature change.

Copyright © 2010 Pearson Education, Inc. Properties of Water Polar solvent properties Water is a solvent that dissolves charged molecules. Facilitates chemical reactions inside and outside our bodies. Hydrophilic- “water loving” Hydrophobic- “water fearing”

Copyright © 2010 Pearson Education, Inc. Properties of Water Cushioning Protects certain organs from physical trauma, e.g., cerebrospinal fluid

Copyright © 2010 Pearson Education, Inc. Organic Compounds Many are polymers—chains of similar units (monomers or building blocks) Synthesized by dehydration synthesis Broken down by hydrolysis reactions

Copyright © 2010 Pearson Education, Inc. Figure Glucose Fructose Water is released Monomers linked by covalent bond Water is consumed Sucrose (a) Dehydration synthesis Monomers are joined by removal of OH from one monomer and removal of H from the other at the site of bond formation. + (b) Hydrolysis Monomers are released by the addition of a water molecule, adding OH to one monomer and H to the other. (c) Example reactions Dehydration synthesis of sucrose and its breakdown by hydrolysis Monomer 1Monomer 2 Monomer 1Monomer 2 +

Copyright © 2010 Pearson Education, Inc. Carbohydrates Sugars and starches Contain C, H, and O [(CH 2 0) n ] Three classes Monosaccharides Disaccharides Polysaccharides

Copyright © 2010 Pearson Education, Inc. Carbohydrates Functions Major source of cellular fuel (e.g., glucose)

Copyright © 2010 Pearson Education, Inc. Figure 2.15a Example Hexose sugars (the hexoses shown here are isomers) Example Pentose sugars GlucoseFructose GalactoseDeoxyriboseRibose (a) Monosaccharides Monomers of carbohydrates

Copyright © 2010 Pearson Education, Inc. Disaccharides Double sugars Too large to pass through cell membranes

Copyright © 2010 Pearson Education, Inc. Figure 2.15b PLAY Animation: Disaccharides Example Sucrose, maltose, and lactose (these disaccharides are isomers) GlucoseFructoseGlucose SucroseMaltoseLactose Galactose (b) Disaccharides Consist of two linked monosaccharides

Copyright © 2010 Pearson Education, Inc. Figure 2.15c PLAY Animation: Polysaccharides Example This polysaccharide is a simplified representation of glycogen, a polysaccharide formed from glucose units. (c) Polysaccharides Long branching chains (polymers) of linked monosaccharides Glycogen

Copyright © 2010 Pearson Education, Inc. Lipids Contain C, H, O (less than in carbohydrates), and sometimes P Insoluble in water Main types: fats Phospholipids Steroids PLAY Animation: Fats

Copyright © 2010 Pearson Education, Inc. Figure 2.16b Phosphorus- containing group (polar “head”) Example Phosphatidylcholine Glycerol backbone 2 fatty acid chains (nonpolar “tail”) Polar “head” Nonpolar “tail” (schematic phospholipid) (b) “Typical” structure of a phospholipid molecule Two fatty acid chains and a phosphorus-containing group are attached to the glycerol backbone.

Copyright © 2010 Pearson Education, Inc. Enzymes Biological catalysts Lower the activation energy, increase the speed of a reaction (millions of reactions per minute!)

Copyright © 2010 Pearson Education, Inc. Figure 2.20 Activation energy required Less activation energy required WITHOUT ENZYMEWITH ENZYME Reactants Product Reactants PLAY Animation: Enzymes

Copyright © 2010 Pearson Education, Inc. Characteristics of Enzymes Often named for the reaction they catalyze; usually end in -ase

Copyright © 2010 Pearson Education, Inc. Figure 2.21 Substrates (S) e.g., amino acids Enzyme (E) Enzyme-substrate complex (E-S) Enzyme (E) Product (P) e.g., dipeptide Energy is absorbed; bond is formed. Water is released. Peptide bond Substrates bind at active site. Enzyme changes shape to hold substrates in proper position. Internal rearrangements leading to catalysis occur. Product is released. Enzyme returns to original shape and is available to catalyze another reaction. Active site + H2OH2O 12 3

Copyright © 2010 Pearson Education, Inc. Figure 2.21, step 1 Substrates (S) e.g., amino acids Enzyme (E) Enzyme-substrate complex (E-S) Substrates bind at active site. Enzyme changes shape to hold substrates in proper position. Active site + 1

Copyright © 2010 Pearson Education, Inc. Figure 2.21, step 2 Substrates (S) e.g., amino acids Enzyme (E) Enzyme-substrate complex (E-S) Energy is absorbed; bond is formed. Water is released. Substrates bind at active site. Enzyme changes shape to hold substrates in proper position. Internal rearrangements leading to catalysis occur. Active site + H2OH2O 12

Copyright © 2010 Pearson Education, Inc. Figure 2.21, step 3 Substrates (S) e.g., amino acids Enzyme (E) Enzyme-substrate complex (E-S) Enzyme (E) Product (P) e.g., dipeptide Energy is absorbed; bond is formed. Water is released. Peptide bond Substrates bind at active site. Enzyme changes shape to hold substrates in proper position. Internal rearrangements leading to catalysis occur. Product is released. Enzyme returns to original shape and is available to catalyze another reaction. Active site + H2OH2O 12 3

Copyright © 2010 Pearson Education, Inc. Summary of Enzyme Action PLAY Animation: How Enzymes Work

Copyright © 2010 Pearson Education, Inc. Nucleic Acids DNA and RNA Largest molecules in the body

Copyright © 2010 Pearson Education, Inc. Deoxyribonucleic Acid (DNA) Four bases: adenine (A), guanine (G), cytosine (C), and thymine (T) Double-stranded helical molecule in the cell nucleus Provides instructions for protein synthesis Replicates before cell division, ensuring genetic continuity

Copyright © 2010 Pearson Education, Inc. Figure 2.22 Deoxyribose sugar Phosphate Sugar-phosphate backbone Adenine nucleotide Hydrogen bond Thymine nucleotide Phosphate Sugar: Deoxyribose Phosphate SugarThymine (T) Base: Adenine (A) Thymine (T) Cytosine (C) Guanine (G) (b) (a) (c) Computer-generated image of a DNA molecule

Copyright © 2010 Pearson Education, Inc. Ribonucleic Acid (RNA) Four bases: adenine (A), guanine (G), cytosine (C), and uracil (U) Single-stranded molecule mostly active outside the nucleus Three varieties of RNA carry out the DNA orders for protein synthesis messenger RNA, transfer RNA, and ribosomal RNA PLAY Animation: DNA and RNA

Copyright © 2010 Pearson Education, Inc. Adenosine Triphosphate (ATP) Energy currency of cells.

Copyright © 2010 Pearson Education, Inc. Figure 2.23 Adenosine triphosphate (ATP) Adenosine diphosphate (ADP) Adenosine monophosphate (AMP) Adenosine Adenine Ribose Phosphate groups High-energy phosphate bonds can be hydrolyzed to release energy.