Chapter 2: Chemistry of Life

1. Chapter 2: Chemistry of Life • Given atomic number and mass, calculate the number of each subatomic particle. • Describe the types of bonds found in molecules. • Calculate concentrations of ions found in pH. • Distinguish between dehydration and hydrolysis reactions. • Describe the structure and function of the four macromolecules.

2. All Matter Consists of Elements Made of Atoms • Atoms, the smallest functional unit, consist of • Protons: positive charge, have mass • Neutrons: no charge, have mass • Electrons: negative charge, have no discernable mass

3. Periodic Table Fig. 2-9 Atomic mass 4 He 2 Helium 2He Hydrogen 1H Atomic number First shell Lithium 3Li Beryllium 4Be Fluorine 9F Boron 5B Nitrogen 7N Neon 10Ne Carbon 6C Oxygen 8O Second shell Chlorine 17Cl Sodium 11Na Aluminum 13Al Silicon 14Si Argon 18Ar Magnesium 12Mg Phosphorus 15P Sulfur 16S Third shell The atomic number gives the number of ____________. Which subatomic particle determines the reactivity? ____ Why are the noble gases inert? _____________________

4. Find the number of sub-atomic particles…

5. Isotopes Definition Useful in: Radioactive dating Body imaging Killing cancer • Same element, same atomic number = same number of protons and electrons • Different number of neutrons = different mass

6. Three Types of Chemical Bonds In order of decreasing bond strength… • Covalent • Polar • Nonpolar • Ionic Table 2.1

7. What would the electron configuration be for dihydrogen monoxide? • What types of bonds form between these molecules?

8. Life Depends on Water • Water is a good solvent • Hydrophilic, hydrophobic • Water facilitates chemical reactions • Water is cohesive & adhesive • Water resists a change in temperature • Frozen water is less dense that liquid water • Water has high specific heat

9. What happens when a hydrogen atom loses an electron? H2O H+ + OH- • H+ ions=protons • The pH scale measures the % of H+ ions in a solution. • Acids are proton donors. • Bases are proton acceptors. Figure 2.8

10. The pH Scale is logarithmic. Figure 2.10

11. Carbohydrates Structure Function Energy storage Structural support • Monomers are monosaccharides • General formula is CH2O • Link 2 together to form a disaccharide • Link many together to form a polysaccharide

12. Making and Breaking Biological Macromolecules • Dehydration • Removal of water • Requires energy • Hydrolysis • Addition of water • Releases energy H H + OH HO C6H12O6 glucose glucose C6H12O6 + monosaccharide monosaccharide

13. Lipids are insoluble in water Structure Function Energy source • Triglycerides (FATS) • 3 Fatty acids + 1 glycerol

14. Lipids Structure Function Component of cell membranes • Phospholipids

15. Lipids Structure Function Component of cell membranes Precursor for hormones • Steroids • Cholesterol

16. Protein Structure

17. Proteins Structure Function Enzymes Structural support Hormones Transport Defense Motion • Primary: order of amino acids • Secondary: alpha helix or beta pleated sheet • Tertiary: 3D shape held by ionic, covalent and hydrogen bonds • Quaternary:multiple tertiary structures combine

18. Proteins: Complex Structures Constructed of Amino Acids • Denaturation • Permanent disruption of protein structure • Can be damaged by temperature or changes in pH • Leads to loss of biological function

19. Nucleic Acids Structure Function Store genetic information Provide information used in making proteins • Nucleotides consist of a phosphate group, a sugar, and a nitrogenous base

20. Nucleic Acids DNA RNA Single-stranded Sugar=ribose Nitrogen bases= AUGC • Double-stranded • Sugar=deoxyribose • Nitrogen bases= ATGC