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Chapter 2 The Chemical Basis of Life Mosby items and derived items © 2007, 2003 by Mosby, Inc. Slide 1 Basic Chemistry • Elements and compounds Matter Slide 2 Basic Chemistry • Element—simple form of matter. “trace elements” - make up less than 2% of body weight • Compound—atoms of two or more elements Slide 3 Basic Chemistry • Atoms John Dalton Slide 4 Basic Chemistry • Atomic structure Protons (+ or p) Neutrons (n) Electrons (– or e) Slide 5 Basic Chemistry • Atomic number and atomic weight Atomic number (Table 2-1) Atomic weight Slide 6 Basic Chemistry • Energy levels (Figures 2-3 and 2-4) number of electrons = the number of protons in the nucleus (in a stable atom) “cloud” Slide 7 Basic Chemistry • Energy levels (cont.) “Bohr model” • concentric circles of the electrons from the nucleus • chemically inert • chemically active Slide 8 Basic Chemistry • Energy levels (cont.) Octet rule Slide 9 QuickTime™ and a decompressor are needed to see this picture. Slide 10 Basic Chemistry • Isotopes Isotopes Radioactive isotope - unstable Slide 11 Basic Chemistry • Attractions between atoms—chemical bonds Chemical reaction Molecule Compound Slide 12 Basic Chemistry • Chemical bonds—two types unite atoms into molecules: Ionic, or electrovalent, bond Covalent bond Slide 13 QuickTime™ and a decompressor are needed to see this picture. Slide 14 Basic Chemistry • Chemical reactions three basic types • • • • Synthesis reaction Decomposition reaction Exchange reaction Reversible reactions Slide 15 Metabolism • Catabolism Break down Release energy hydrolysis End products • Anabolism Join dehydration synthesis Slide 16 Organic and Inorganic Compounds chemical makeup • Inorganic compounds • Organic compounds Slide 17 Inorganic Compounds • Water Properties of water (Table 2-2) • Polarity Polarity - allows water to serve as a solvent • Solvent • Temperature regulation Slide 18 Inorganic Compounds cont’d • Oxygen • Carbon dioxide - waste product of cellular respiration and acid/base balance • Electrolytes Slide 19 Inorganic Compounds Acids and bases • Acids “acidity” Release hydrogen • Bases Release hydroxide “alkalinity” Slide 20 Inorganic Compounds • pH scale pH of 7 - neutrality pH of less than 7 - acidity; pH of more than 7 - alkalinity Slide 21 Inorganic Compounds • Buffers Maintain the constancy of the pH Minimize changes in the concentrations of H+ and OH– ionsInorganic Compounds Slide 22 Organic Compounds • Carbohydrates, proteins, lipids, nucleic acids Slide 23 Organic Molecules • Carbohydrates Monosaccharides—simple Disaccharides sugars and polysaccharides Slide 24 Organic Molecules • Proteins (Table 2-5) Chainlike polymers Amino acids • Essential amino acids • Nonessential amino acids Slide 25 Organic Molecules • Levels of protein structure There are four levels of protein organization: • Primary structure • Secondary structure • Tertiary structure • Quaternary structure Slide 26 QuickTime™ and a decompressor are needed to see this picture. Slide 27 Organic Molecules - Two broad categories • Structural proteins form the structures of the body • Functional proteins cause chemical changes in the molecules Shape of a protein’s molecules determines its function • Denatured proteins denatured by changes in pH, temperature, radiation, and other chemicals Slide 28 QuickTime™ and a decompressor are needed to see this picture. Slide 29 Organic Molecules • Lipids (Table 2-6) • Types: triglycerides, phospholipids, steroids, prostaglandins) Major roles: • Energy source • Structural role • Integral parts of cell membranes Slide 30 Organic Molecules • Lipids (cont.) Triglycerides (fats) • building blocks of triglycerides : glycerol and fatty acids Types of fatty acids— – saturated fatty acid (animal fat) – unsaturated fatty acid (plant oil) Triglycerides - formed by a dehydration synthesis Slide 31 Organic Molecules • Lipids (cont.) Phospholipids (make up cell membranes) • (hydrophilic)(hydrophobic) • Double layer (bi layer) - cell membranes Slide 32 Organic Molecules Steroids • Main component is steroid nucleus • Involved in many structural and functional roles Slide 33 Organic Molecules Prostaglandins • “tissue hormones” • Variety of functions (blood pressure, secretion of digestive fluids, etc.) Slide 34 Nucleic Acids • Two Nucleic acids DNA RNA • Made of thousand of nucleotides. • Nucleotides - Made of a sugar, a base, and a phosphate group Slide 35 DNA • DNA (deoxyribonucleic acid) • Made up of Nucleotides • Nucleotides contain: sugar (deoxyribose), phosphate group, base (the arrangement of the bases codes for the coding of proteins) • • • • cytosine, guanine thymine, Adenine Slide 36 DNA cont’d Base pairs attach in the center of the helix and hold two parts of DNA molecule together all DNA molecules in one individual are identical and different from those in all other individuals molecule of heredity - passes on genetic makeup to next generation Slide 37 RNA • RNA (ribonucleic acid) sugar phosphate group, base • adenine, uracil, guanine, or cytosine (uracil replaces thymine) Functions - carry blue print for protein to the ribosome, turn off genes in DNA Slide 38 ATP ATP - Adenosine tri-phosphate - special kind of nucleotide • Adenosine (sugar) and 3 phosphates • High-energy bonds • Cleavage releases energy • energy currency of cells (ADP) Adenosine diphosphate • Circulates waiting for another phosphate • so that it can become ATP Slide 39 DNA Structure QuickTime™ and a decompressor are needed to see this picture. Slide 40 DNA replication and protein synthesis QuickTime™ and a decompressor are needed to see this picture. Slide 41