Chemistry of Life

1. Chemistry of Life

2. I. Nature of Matter Chemistry will help you learn about biology because you’re a chemical machine.

3. A. Atoms • All matter consists of atoms. • An atom is the smallest unit of matter that cannot be broken down.

4. A. Atoms Draw an atom including the electron cloud.

5. A. Atoms 3 Types of particles make up an atom: • Electrons Negatively charged (-) • Protons Positively charged (+) • Neutrons No charge

6. A. Atoms • Electrons form the electron cloud which has a negative charge • Atoms typically have one electron for each proton Example: 3 electrons (-), 3 protons (+) = no charge (neutral)

7. B. Elements • 100 known elements • Elements differ in the number of protons they have Ex. Hydrogen has 1 proton & 1 electron Oxygen has 8 protons & 8 electrons • Neutrons are sometimes equal to the number of protons

8. B. Elements Isotopes- atoms of an element that contain different numbers of neutrons Example-Carbon-12, Carbon-13, Carbon-14 Carbon-12 has 6 protons and 6 neutrons Carbon-13 has 6 protons and 7 neutrons Carbon-14 has 6 protons and 8 neutrons

9. C. Chemical Bonding -a force that joins atoms of 2 or more different elements Compound-made of the joined atoms of 2 or more different elements. Ex. Na (sodium) + Cl (chloride)  NaCl (table salt)

10. 1. Covalent Bonds • Form when 2 or more atoms share electrons to form a molecule. • Examples of covalent bonds: CO2 , H2O

11. 1. Covalent Bonds Electron arrangement: Hydrogen and Helium hold up to 2 electrons in the outer level; all other atoms can hold up to 8 electrons in the outer level Outer level electrons are called “valence electrons”.

12. 2. Hydrogen Bonds in H2O • The water molecules have a partial positive and negative end. This is called POLAR. • Polar molecules have an uneven distribution of charge

13. 3. Ionic Bonds • Form IONS Ions-Atom or molecule that loses or gains an electron; they have an electrical charge because of unequal # of protons and electrons • Ions of opposite charge may interact to form an ionic bond Example: Draw an ionic bond in Na Cl Na Cl  NaCl

14. Water and SolutionsA. Water in Living Things • 70% of the human body is water • Cells are filled with water and are surrounded by water.

15. A. Water in Living Things Properties of Water 1. Storage of heat: Water heats slowly and retains heat longer than many other substances. Example: Some organisms release excess heat by sweating (cool off) Feet have more sweat glands than any other part of the body (250,000) and can produce up to a pint of perspiration each day.

16. A. Water in Living Things Properties of Water 2. Cohesion: attraction between substances of the same kind • Cohesion is caused by the hydrogen bonds between water molecules • Surface Tension: caused by the attraction of water molecules http://www.youtube.com/watch?v=45yabrnryXk

17. A. Water in Living Things Properties of Water 3. Adhesion: attraction between different substances • Adhesion powers capillary action in which water molecules move water through a narrow tube such as a stem of a plant • The attraction of the water to the walls of the tube sucks the water up more strongly than gravity pulls it down.

18. A. Water in Living Things Adhesion Water moves up a plant through a combination of capillary action, cohesion, and other factors

19. Aqueous Solutions What is a solution? A mixture in which one or more substances are evenly distributed in another substance. Importance of solutions in the body Certain substances that dissolve in water can move within and between cells (e.x. sugar)

20. 1. Polarity of Solutions • Ionic compounds and polar molecules dissolve best in water. Nonpolar molecules DO NOT. • Cell membranes depend on the interaction of polar and nonpolar molecules.

21. 2. Acids and Bases • When hydrogen bonds in H2O break, a hydrogen (H+) ion and a hydroxide ion (OH-) forms Draw this: H2O  H+ + OH-

22. 2. Acids and Bases Water has an equal # of H+ and OH- ions Acids-have a high concentration of H+ ions Bases-have a lower concentration of H+ ions and forms OH- ions pH scale-measures the concentration of H+ ions in a solution

23. 2. Acids and Bases Draw the pH scale

24. III. Chemistry of Cell Macromolecules “Building Blocks” • Organic compounds contain Carbon atoms that are covalently bonded to other elements. • 4 classes of organic compounds found in living things: 1. carbohydrates 3. protein 2. lipids 4. nucleic acid

26. Carbohydrates -are made up of carbon, hydrogen, and oxygen atoms in 1:2:1 ratio • -are a key source of energy • -are found in most foods, especially fruits, vegetables, and grains

27. Monosaccharides • Monosaccharides -single sugars • Examples: glucose, fructose • Function: as a major source of energy in cells

28. Disaccharides • Disaccharides-double sugars (2 monosaccharides) • Examples: sucrose (made of glucose and fructose)

29. Polysaccharides • Polysaccharides-3 or more monosaccharides • Examples: starch • Function: storehouses of the energy stored in sugar • Starch-Stored by plants • Glycogen-made and stored by animals

30. Lipids • Lipids are nonpolar and are NOT soluble in water • Lipids include: fats, phospholipids, steroids, and waxes • Fats-Store energy • Phospholipids-Form cell membranes

31. Lipids *** Examine the difference between saturated and unsaturated fatty acids. * Saturated fats are solid at room temperature * Unsaturated fats are liquid at room temperature

32. Proteins • Large molecules formed by amino acids • AMINO ACIDS ARE THE BUILDING BLOCKS OF PROTEIN.

33. Proteins tend to fold into compact shapes

34. Functions of Proteins • Some proteins are enzymes and promote chemical reactions. • Collagen is a protein found in skin, ligaments, tendons, and bones. • Antibodies defend against infection. • Aid in muscle contraction • Hemoglobin is a protein found in blood that carries oxygen from the lungs to body tissues.

35. Nucleic Acids • Found in ALL cells • It is a long chain of smaller molecules called nucleotides (A, T, G, U and C) • 2 types of Nucleic acids

36. Nucleic Acids • DNA-deoxyribonucleic acid: made of 2 strands; stores hereditary information • RNA-ribonucleic acid; made of 1 strand ; manufactures proteins

37. Nucleic Acids ENERGY MOLECULE IS ATP. ATP is adenosine triphosphate; temporarily stores energy

39. Energy and Chemical Reactions • A. What is energy? Ability to move or change matter • Forms of energy include: light heat chemical mechanical electrical

40. IV. Energy and Chemical Reactions

41. A. What is energy? In chemical reactions energy is stored or released. Reactants  Products NaCl  Na+ + Cl-

42. B. Activation Energy Activation Energy-energy needed to start a chemical reaction It is a “push” that starts a chemical reaction

43. C. Enzymes Enzymes-increase the speed of chemical reactions • Most enzymes are proteins. • Decrease the amount of energy needed to start a chemical reaction

44. C. Enzymes • Allow organisms to maintain homeostasis • Example: Carbonic anhydrase allows your body to eliminate CO2 efficiently • Draw the reaction CO2 + H2O H2 CO3 Carbonic anhydrase

45. C. Enzymes • Enzyme specificity-Enzymes act on only certain substances during a chemical reaction • These substances are called substrates

46. C. Enzymes Label active site, substrate, and enzyme

47. C. Enzymes What can effect enzyme activity? pH or temperature