1. Chapter 2 The Chemistry of Life

2. Atoms Atoms are the smallest part of matter Atoms are the smallest part of matter Made up of Made up of Protons – Positive charge, found in Protons – Positive charge, found in nucleus nucleus Neutrons – no charge, found in nucleus Neutrons – no charge, found in nucleus Electrons – Negative charge, found Electrons – Negative charge, found outside the nucleus outside the nucleus

3. Determining atomic number, atomic weight and neutrons Atomic number is the number of protons in the atom Atomic number is the number of protons in the atom Atomic weight is the sum of the mass of the protons, neutrons, and electrons in an atom Atomic weight is the sum of the mass of the protons, neutrons, and electrons in an atom Number of neutrons can be determined by subtracting the atomic number from the atomic mass (rounded). Number of neutrons can be determined by subtracting the atomic number from the atomic mass (rounded).

4. Electron shell model

5. Electron placement Electron placement Bohr atom vs. modern interpretation Bohr atom vs. modern interpretation

6. Compounds and molecules Compounds and molecules Compound - two or more elements chemically combined; Hydrogen and Oxygen combine to form water Compound - two or more elements chemically combined; Hydrogen and Oxygen combine to form water Molecule - smallest unit of a compound that retains the properties of the compound; H 2 O Molecule - smallest unit of a compound that retains the properties of the compound; H 2 O

7. B. Chemical Bonding

8. 1. Ionic bonding 1. Ionic bonding Giving away or taking of electrons Giving away or taking of electrons Ionic bond formation in sodium chloride Ionic bond formation in sodium chloride 2. Covalent bonding 2. Covalent bonding Sharing of electrons Sharing of electrons Covalent bond formation in methane Covalent bond formation in methane 3. Hydrogen bonding 3. Hydrogen bonding formed by the attraction of oppositely charged poles of molecules. Example in water; a weak bond formed by the attraction of oppositely charged poles of molecules. Example in water; a weak bond

9. Properties of Water Because of the hydrogen bonds between water molecules, water is “sticky” Because of the hydrogen bonds between water molecules, water is “sticky” Cohesion – Water sticks to itself (penny lab) Cohesion – Water sticks to itself (penny lab) Adhesion – Water sticks to other surfaces (capillary action, wet) Adhesion – Water sticks to other surfaces (capillary action, wet)

11. 4. Chemical reactions 4. Chemical reactions Chemical reaction - process in which atoms or molecules interact and form new bonds. Chemical reaction - process in which atoms or molecules interact and form new bonds. Can be characterized by release or taking in of heat, color change, gas, etc. Can be characterized by release or taking in of heat, color change, gas, etc. 5. Acids and bases 5. Acids and bases Acids have a pH below 7, sour tasting and turn litmus paper red Acids have a pH below 7, sour tasting and turn litmus paper red Bases have a pH above 7, taste bitter, and turn litmus paper blue Bases have a pH above 7, taste bitter, and turn litmus paper blue

12. pH Scale

13. C. Major Organic Compounds of Living Things

14. 1. Carbohydrates 1. Carbohydrates Composed of carbon, hydrogen, and oxygen Composed of carbon, hydrogen, and oxygen Monosaccharides, disaccharides, and polysaccharides Monosaccharides, disaccharides, and polysaccharides Important as a food source Important as a food source 2. Lipids 2. Lipids Fats; found in cell membranes, steroids Fats; found in cell membranes, steroids Used for energy storage Used for energy storage Generally do not dissolve in water Generally do not dissolve in water

16. 3. Proteins 3. Proteins Composed of long chains of amino acids Composed of long chains of amino acids Include enzymes and structural materials Include enzymes and structural materials Primary, secondary, and tertiary protein structure; can be denatured Primary, secondary, and tertiary protein structure; can be denatured 4. Nucleic acids 4. Nucleic acids Composed of a sugar, phosphate and nitrogenous bases Composed of a sugar, phosphate and nitrogenous bases Bases: Adenine, Guanine, Cytosine, Thymine, Uracil Bases: Adenine, Guanine, Cytosine, Thymine, Uracil Hereditary material Hereditary material

18. Enzymes Special proteins that speed up and control chemical reactions Special proteins that speed up and control chemical reactions Usually named after the substances they act upon Usually named after the substances they act upon Often end in –ase Often end in –ase Catalase, Lactase, Ribonuclease, etc. Catalase, Lactase, Ribonuclease, etc. Animation Animation Animation

19. Enzymes lower acivation energy

21. Enzymes Lower the amount of energy needed for a reaction to proceed Lower the amount of energy needed for a reaction to proceed Are not used up during the reaction, and can be used over and over again Are not used up during the reaction, and can be used over and over again Control your body’s metabolism (all chemical reactions in your body) Control your body’s metabolism (all chemical reactions in your body) Are affected by heat, temperature, and pH, they can be denatured (destroyed) Are affected by heat, temperature, and pH, they can be denatured (destroyed)