1. Chapter 2 The Chemistry of Life 1/39

2. 2.1 The Nature of Matter Atoms – = basic unit of matter – Made of 3 subatomic particles Protons Neutrons Electrons 3/39

3. 2.1 The Nature of Matter Atoms are made of subatomic particles – Protons Positive charge In the nucleus – Neutrons No charge In the nucleus – Electrons Negative charge Fly around the nucleus EXTREMELY SMALL – 1/1840 the mass of a proton 4/39

4. 2.1 The Nature of Matter (continued) Atoms are neutral – They have an equal # of protons (positives) and electrons (negatives) Elements – Pure substance, only 1 kind of atom – Abbreviate with 1 or 2 letters 5/39

5. 2.1 The Nature of Matter (continued) Isotopes – Atoms of an element with a different number of neutrons – Identified by their mass number Atomic Mass – The mass of the atom (protons & neutrons) chart pg 29 Isotopes of Carbon CarbonElectronsProtonsNeutrons 12 (not radioactive)666 13 (not radioactive)667 14 (radioactive)668 6/39

6. 2.1 The Nature of Matter (continued) Radioactive Isotopes – Nucleus is not stable. It breaks down over time. – Can be dangerous – Can be helpful Cancer treatments Killing bacteria Geological dating 7/39

7. 2.1 The Nature of Matter (continued) Compound – Substance formed by chemical combination of 2 or more elements in definite proportion – Chemical formulas show the composition H 2 O or NaCl – The compound’s physical & chemical properties are different than the elements that make the compound. » Water » Salt 8/39

8. 2.1 The Nature of Matter (continued) Chemical Bonds – 2 main types: ionic & covalent Ionic Bonds (Figure bottom p30) – Electrons move from one atom to another. – When they move, the atom becomes charged (either positive if it loses an electron or negative if it gains an electron) – The charge forms the bond that holds! 9/39

9. 2.1 The Nature of Matter (continued) Covalent Bonds (Figure p 31) – Forms when atoms share electrons – Double & triple bonds form when 4 or 6 electrons are shared – Molecules Structures formed when atoms are joined together by covalent bonds Smallest unit of most compounds 10/31

10. 2.2 Properties of Water Water – Most abundant compound in living things The Water Molecule – Is neutral (10 protons & 10 electrons) – Is polar The O 2 atom has more protons. It attracts the H’s electrons more than the 1 proton in the H. O 2 end slightly negative/H 2 end slightly positive. There is an uneven electron distribution between the O & H atoms Polar molecules attract each other 11/31

11. 2.2 Properties of Water (continued) The Water Molecule (continued) – Hydrogen bonds can form between molecules Weaker than ionic or covalent Responsible for water’s special properties – Cohesion – Adhesion 12/39

12. 2.2 Properties of Water (continued) Cohesion – The attraction between molecules of the same substance Surface is drawn in, drops are formed Force that allows insects to walk on water Adhesion – The attraction between molecules of different substances Water rises in narrow tubes (water & glass) = capillary action – Occurs in plants  roots to stems/leaves 13/39

13. 2.2 Properties of Water (continued) Heat Capacity – The amount of heat energy needed to increase a substances temperature To heat up, molecules must move faster Hydrogen bonds make moving hard, so it takes a lot of heat to get water to warm up (move H bonds) Click here for Crash Course Water Liquid Awesome 11:16 14/39

14. 2.2 Properties of Water (continued) Mixture – Two or more elements or compounds that are PHYSICALLY mixed together Two types – Solutions » Components are evenly distributed throughout – Suspensions » Mix of water and non-dissolved material that does not settle out 15/39

15. 2.2 Properties of Water (continued) Solutions – Solute The substance that is being dissolved – Solvent The substance that is doing the dissolving Water’s polarity allows it to dissolve both ionic and other polar molecules. Water is the GREATEST solvent on Earth! 16/39

16. 2.2 Properties of Water (continued) Suspensions – Some materials don’t dissolve in water, but separate into small pieces that don’t settle out – Is a mixture of water & non-dissolved materials Blood is a suspension. It contains cells & other non- dissolved particles that remain in suspension. 17/39

17. 2.2 Properties of Water (continued) Acids, Bases, and pH – A water molecule can react to form ions H 2 O  H + and OH – Water  hydrogen and hydroxide ions ions 18/39

18. 2.2 Properties of Water (continued) pH scale – measures the concentration of hydrogen ions (H + ) – Range is from 0 to 14 – 7 is neutral where hydrogen & hydroxide ions are equal – >7 is basic more hydroxide ions (OH - ) – <7 is acidic more hydrogen ions (H + ) 19/39

19. 2.2 Properties of Water (continued) Acids – A compound that forms H ions in solution contain higher concentration of H + ions than pure water & have pH values < 7 Bases – A compound that forms OH ions in solution contain lower concentrations of H+ ions than pure water and have pH values >7 20/39

20. 2.2 Properties of Water (continued) Buffers – Are weak acids or bases that react with strong acids or bases to prevent sharp changes in pH. Our body controls pH is through dissolved substances called buffers. 21/39

21. 2.3 Carbon Compounds The Chemistry of Carbon – 4 valence electrons Each can form strong covalent bond – Can bond with many elements Including H, O, P, S, N – *IMPT* Carbon can bond with Carbon!!! Chains can form C to C bonds can be single, double, or triple – Rings can form too (figure pg 37 bottom) 23/39

22. Macromolecules – Large molecules made from smaller ones – Formed by polymerization (page 38 bottom) = when small molecules join to form larger molecules Small molecules are called monomers Monomers join to form polymers 2.3 Carbon Compounds (continued) 24/39 Click here for Mr. Anderson Biological Molecules

23. Carbohydrates – Compounds with atoms in a 1: 2 :1 ratio Carbon : Hydrogen : Oxygen Example: C 6 H 12 O 6 – Made of sugar molecules (monomers) – Living things use carbs as their main energy source – Plants use carbs for structure (cellulose) 2.3 Carbon Compounds (continued) 25/39

24. Carbohydrates (continued) – Living things store extra sugar as complex carbs like starch (figure page 39) Simple Sugars = monosaccharides – Glucose, galactose, fructose Complex Carbohydrates = polysaccharides – Formed from monosaccharides 2.3 Carbon Compounds (continued) 26/39

25. Lipids (fats, oils, waxes) – Not soluble in water – Made of fatty acids (monomers) – Lipids can store energy – Are impt parts of membranes & waterproof coverings 2.3 Carbon Compounds (continued) 27/39

26. Lipids (continued) – Glycerol combined w/ a fatty acid (page 39 right side) Saturated Fatty Acid – Each C atom in chain is joined by a single bond to next C – Solid at room temperature (think steak) Unsaturated Fatty Acid – At least one C is double bonded to the next C – Liquid at room temperature (think olive oil) 2.3 Carbon Compounds (continued) 28/39

27. Nucleic Acids – Made of nucleotides (monomers) Each nucleotide is made of three parts – 5 carbon sugar – phosphate group – nitrogenous base (figure top of page 40) 2.3 Carbon Compounds (continued) 29/39

28. Nucleic Acids (continued) – Store & transmit hereditary (genetic) information – 2 types RNA – Contains the sugar ribose – Ribonucleic acid DNA – Contains the sugar deoxyribose – Deoxyribonucleic acid 2.3 Carbon Compounds (continued) 30/39

29. Proteins – Made of amino acids (monomers) There are >20 different amino acids (bottom page 40) DNA gives the directions on the order which amino acids are to be joined and proteins are formed. – Proteins (1) control the rate of reactions & regulate cell processes, (2) form bones & muscles (3) transport substances in/out of our cells (4) help fight disease. 2.3 Carbon Compounds (continued) 31/39

30. 2.3 Carbon Compounds (continued) Four levels of protein organization – 1. Amino acids form a protein chain – 2. Amino acids can fold – 3. 3D arrangement of the chain – 4. If >1 chain, the chains become inter-twined into specific shapes 32/39

31. 2.4 Chemical Reactions & Enzymes Everything that happens in an organism is based on chemical reactions! – A process that transforms one set of chemicals into another – Mass & energy are conserved (remember your geophys!) 33/39

32. 2.4 Chemical Reactions & Enzymes (cont) Chem RXNS – Can be fast or slow – Elements or compounds entering reaction are REACTANTS (retry, retry till you become a pro!) – Elements or compounds exiting reaction are PRODUCTS – Involve changes in chemical bonds – Very impt reaction in our body Fig 2-19 CO 2 and H 2 O yield H 2 CO 3 yield CO 2 and H 2 O 34/39

33. 2.4 Chemical Reactions & Enzymes (cont) Energy is released OR absorbed whenever chemical bonds are made or broken – Chem rxns that release energy are often spontaneous. – Chem rxns that absorb energy will not occur without a source of energy To stay alive, organisms need energy – Plants trap sun’s energy – Animals eat 35/39

34. 2.4 Chemical Reactions & Enzymes (cont) Activation Energy (Fig 2-20) – = the energy needed to get a reaction started – Is involved with all chem rxns regardless of whether the whole reaction releases or absorbs energy 36/39

35. 2.4 Chemical Reactions & Enzymes (cont) Enzymes – Some of life’s rxns are too slow or have activation energy needs that are too high to make it possible to take place in an organism – Note they are LIFE reactions – so how do they occur Catalysts get involved – A substance that speeds up the rate of a chemical reaction. They lower the activation energy needed 37/39

36. 2.4 Chemical Reactions & Enzymes (cont) Enzymes (continued) – Are proteins that are biological catalysts! Meaning they lower activation energy Fig page 42 – If this reaction were left to itself, CO2 would build up too quickly in our bodies – Carbonic anhydrase is the enzyme that speeds up the reaction – Are very specific – End in -ase 38/39

37. 2.4 Chemical Reactions & Enzymes (cont) Enzymes – Enzyme-Substrate Complex Substrates (reactants) bind to the enzyme’s active site Fit is so precise! Reaction takes place – Temp, pH, other molecules can affect the activity of enzymes Most body enzymes work best at 98.6°F (37°C) Our stomach enzymes work best in acidic environment! 39/39