Biology 20 The Molecules of Cells Page 1 of 5 Biology 20 The Molecules of Life Organic chemistry: CARBON: - Atomic # = , therefore has valence (outer shell) electrons - Forms covalent bonds with: Hydrocarbons Ex. 6 FUNCTIONAL GROUPS: (p. 35; Table 3.2 & Fig. 3.2) 1. HYDROXYL GROUP 2. CARBONYL GROUP ALDEHYDES (C dbl bond O at the end) KETONES (C dbl bond O in middle) 3. CARBOXYL GROUP carboxylic acids. 4. AMINo GROUP amines 5. PHOSPHATE GROUP Ex. ATP ---> ADP + Pi 6. METHYL GROUP Macromolecules: 4 classes of macromolecules in living organisms: 1. Carbohydrates 2. Proteins 3. Nucleic acids 4. Lipids Classifying organic compounds: Monomers: Polymers:Biology 20 The Molecules of Cells Page 2 of 5 Formation of polymers: (p. 36; Figure 3.3A) Dehydration reactions (synthesis): Ex. glucose + glucose = maltose Breaking of polymers: (p. 36; Figure 3.3B) Hydrolysis (water;loosening or splitting) Ex. digestive enzymes Types of Macromolecules: CARBOHYDRATES: Classified by: 1. Monosaccharides = (mono = single; sacchar = sugar) (p. 37; fig. 34B&C) Simple sugar composed of: Major nutrient for cells, with glucose being the most common. Can be produced by photosynthesis from CO2, H2O & sunlight. Photosynthesis: 6CO2 + 6H2O + sunlight ---> C6H12O6 + 6O2 Used in cellular respiration. Respiration: C6H12O6 + 6O2 ---> 6CO2 + 6H2O Can be used into forming disacchrides & polysaccharides. 2. Disaccharides =(Di = two; saccharide = sugar) Results from the removal of: (p. 38; fig. 3.5) Disaccharide Monomers Usage Maltose Lactose Sucrose 3. Polysaccharide: (p. 39; fig. 3.7) -2 important biological functions: 1. Energy storage (starch & glycogen) a) Starch: b) Glycogen: 2. Structural support (cellulose & chitin) a) Cellulose: b) Chitin:Biology 20 The Molecules of Cells Page 3 of 5 PROTEINS: (pp. 42-45; Figures 3.12 – 3.18) Peptide bond (p. 43; Fig. 3.13): -N-C-C-N-C-C- = backbone Polypeptide chain = There are 20 amino acids which make up proteins. Amino acids contain both carboxyl and amino functional groups. Levels of protein structure (p. 45; Figs. 3.15 – 3.18): a) Primary structure (1˚): b) Secondary structure (2˚): 2 types of secondary structure: αααα helix ß pleated sheet c) Tertiary structure (3˚): 1. Weak interactions (but cumulatively make it stable) a) b) c) 2. Covalent linkage disulfide bridges d) Quaternary structure (4˚): Ex. Hemogoblin = 4 subunits Denaturation: Causes of denaturation: 1. 2. 3. 4. 8 Functions of proteins: 1. structural support 2. storage 3. transport 4. hormonal 5. receptor 6. contractile 7. defense 8. enzymaticBiology 20 The Molecules of Cells Page 4 of 5 NUCLEIC ACIDS: (p. 46 - 47; Figs. 3.19 - 3.20A & B) Nucleotide = building block of a nucleic acid; composed of: a) Pentose (5-C sugar) b) Nitrogeneous bases: Pyrimidine: Purine: c) Phosphate Group: 3 Examples of Nucleotide based molecules: 1. DNA = deoxyribonucleic acid DNA: the double helix = 3-D shape = Watson & Crick => 1953 Contains: 2. RNA = ribonucleic acid Contains: 3. ATP = adenosine triphosphate Functions of Nucleotide based molecules a) b) c) d) LIPIDS: (p. 40 – 41) 1. Fats: macromolecules constructed from: a) glycerol = 3C -OH b) Fatty acid (carboxylic acid) carboxyl: hydrocarbon tail: Formation of fats (p. 40; Fig. 3.8 B & C) Triglycerides: SATURATED UNSATURATED Ex. Ex.Biology 20 The Molecules of Cells Page 5 of 5 2. Phospholipids Composed of: Hydrophilic heads & Hydrophobic tails Micelles: Surfactant (surface active agent): 3. Steroids (p. 41; Fig. 3.9) Functions of lipids: 1. 2. 3. 4. 5.