1. 1. ALL LIVING THINGS ARE COMPOSED OF CELLS-CELL THEORY 2. LIVING THINGS CHANGE AND DEVELOP OVER TIME-EVOLUTION 3. GENES ARE THE PRIMARY UNITS OF INHERITANCE 4. AN OPEN SYSTEM CAN REGULATE ITS INTERNAL ENVIRONMENT TO MAINTAIN STABLE CONDITIONS-HOMEOSTASIS 5. SURVIVAL OF LIVING ORGANISMS DEPENDS UPON THE CONTINUOUS INPUT OF ENERGY The 5 Themes of Biology

2. MRS. KIM BURKHART The Chemistry of Life

3. Copyright Pearson Prentice Hall Atoms The study of chemistry begins with the basic unit of matter, the atom.

4. Copyright Pearson Prentice Hall Atoms Atoms contain subatomic particles that are even smaller.

5. Copyright Pearson Prentice Hall Atoms The subatomic particles that make up atoms are  protons  neutrons  electrons

6. Copyright Pearson Prentice Hall Atoms The subatomic particles in a helium atom.

7. Copyright Pearson Prentice Hall Elements and Isotopes A chemical element is a pure substance that consists entirely of one type of atom. C stands for carbon. Na stands for sodium.

8. Copyright Pearson Prentice Hall Elements and Isotopes The number of protons in an atom of an element is the element's atomic number. Commonly found in living organisms:

9. Copyright Pearson Prentice Hall Elements and Isotopes Isotopes Atoms of the same element that differ in the number of neutrons they contain are known as isotopes.

10. Copyright Pearson Prentice Hall Elements and Isotopes Because they have the same number of electrons, all isotopes of an element have the same chemical properties.

11. Copyright Pearson Prentice Hall Elements and Isotopes Radioactive Isotopes Some isotopes are radioactive, meaning that their nuclei are unstable and break down at a constant rate over time

12. Copyright Pearson Prentice Hall Elements and Isotopes Radioactive isotopes can be used:  to determine the ages of rocks and fossils.  to treat cancer.  to kill bacteria that cause food to spoil.  as labels or “tracers” to follow the movement of substances within an organism.

13. Copyright Pearson Prentice Hall Chemical Compounds A chemical compound is a substance formed by the chemical combination of two or more elements in definite proportions.

14. Copyright Pearson Prentice Hall Chemical Compounds Chemical Formula Water Table Salt Hydrochloric Acid Glucose

15. Copyright Pearson Prentice Hall Chemical Bonds The atoms in compounds are held together by chemical bonds. The electrons that are available to form bonds are called valence electrons.

16. Copyright Pearson Prentice Hall Chemical Bonds An ionic bond is formed when one or more electrons are transferred from one atom to another. These positively and negatively charged atoms are known as ions.

17. Copyright Pearson Prentice Hall Chemical Bonds A covalent bond forms when electrons are shared between atoms.  single covalent bond  double bond  triple bond

18. Copyright Pearson Prentice Hall Chemical Bonds The structure that results when atoms are joined together by covalent bonds is called a molecule.

19. Copyright Pearson Prentice Hall The Water Molecule A water molecule is polar because there is an uneven distribution of electrons between the oxygen and hydrogen atoms.

20. Copyright Pearson Prentice Hall The Water Molecule Water Molecule

21. Copyright Pearson Prentice Hall The Water Molecule Hydrogen Bonds Because of their partial positive and negative charges, polar molecules can attract each other.

22. Copyright Pearson Prentice Hall The Water Molecule Cohesion is an attraction between molecules of the same substance. Because of hydrogen bonding, water is extremely cohesive.

23. Copyright Pearson Prentice Hall The Water Molecule Adhesion is an attraction between molecules of different substances.

24. Copyright Pearson Prentice Hall Solutions and Suspensions A mixture is a material composed of two or more elements or compounds that are physically mixed but not chemically combined.

25. Copyright Pearson Prentice Hall Solutions and Suspensions Solutions All the components of a solution are evenly distributed throughout the solution. solute—the substance that is dissolved. solvent—the substance in which the solute dissolves.

26. Copyright Pearson Prentice Hall Solutions and Suspensions When a crystal of table salt is placed in warm water, sodium and chloride ions are attracted to the polar water molecules. Na + Cl - Water

27. Copyright Pearson Prentice Hall Solutions and Suspensions Suspensions Some materials do not dissolve when placed in water but separate into pieces so small that they do not settle out easily.

28. Copyright Pearson Prentice Hall Acids, Bases, and pH A water molecule is neutral, but can react to form hydrogen and hydroxide ions. H 2 O   H + + OH -

29. Copyright Pearson Prentice Hall Acids, Bases, and pH The pH scale Chemists devised a measurement system called the pH scale to indicate the concentration of H + ions in solution. The pH scale ranges from 0 to 14.

30. Copyright Pearson Prentice Hall Acids, Bases, and pH At a pH of 7, the concentration of H + ions and OH - ions is equal. The pH Scale Human blood Milk Sea water Normal rainfall Pure water

31. Copyright Pearson Prentice Hall Acids, Bases, and pH An acid is any compound that forms H + ions in solution.

32. Copyright Pearson Prentice Hall Acids, Bases, and pH Bases A base is a compound that produces hydroxide ions (OH - ions) in solution.

33. Copyright Pearson Prentice Hall Acids, Bases, and pH The pH of the fluids within most cells in the human body must generally be kept between 6.5 and 7.5. Controlling pH is important for maintaining homeostasis.

34. Copyright Pearson Prentice Hall The Chemistry of Carbon Organic chemistry is the study of all compounds that contain bonds between carbon atoms.

35. Copyright Pearson Prentice Hall Macromolecules Macromolecules are formed by a process known as polymerization.

36. Copyright Pearson Prentice Hall Macromolecules Four groups of organic compounds found in living things are:  carbohydrates  lipids  nucleic acids  proteins

37. Copyright Pearson Prentice Hall Carbohydrates What is the function of carbohydrates? Source of Energy Structure

38. Copyright Pearson Prentice Hall Carbohydrates Carbohydrates are compounds made up of carbon, hydrogen, and oxygen atoms, usually in a ratio of 1 : 2 : 1.

39. Copyright Pearson Prentice Hall Carbohydrates Different sizes of carbohydrates: Monosaccharides Disaccharides Polysaccharides

40. Copyright Pearson Prentice Hall Carbohydrates Starches and sugars are examples of carbohydrates that are used by living things as a source of energy. Glucose Starch Examples: Cellulose Starch Glycogen

41. Copyright Pearson Prentice Hall Lipids Lipids are generally not soluble in water. The common categories of lipids are: fats oils waxes steroids

42. Copyright Pearson Prentice Hall Lipids

43. Copyright Pearson Prentice Hall Nucleic Acids Nucleic acids are polymers assembled from individual monomers known as nucleotides.

44. Copyright Pearson Prentice Hall Nucleic Acids Nucleotides consist of three parts:  a 5-carbon sugar  a phosphate group  a nitrogenous base

45. Copyright Pearson Prentice Hall Nucleic Acids Nucleic acids store and transmit hereditary, or genetic, information. ribonucleic acid (RNA) deoxyribonucleic acid (DNA)

46. Copyright Pearson Prentice Hall Proteins Proteins are macromolecules that contain nitrogen, carbon, hydrogen, and oxygen. polymers of molecules called amino acids.

47. Copyright Pearson Prentice Hall Proteins

48. Copyright Pearson Prentice Hall Proteins The portion of each amino acid that is different is a side chain called an R-group.

49. Copyright Pearson Prentice Hall Proteins The instructions for arranging amino acids into many different proteins are stored in DNA. Amino Acids Protein Molecule

50. Copyright Pearson Prentice Hall Proteins Some functions of proteins:  Control rate of reactions – Enzymes  Used to form bones and muscles  Transport substances into or out of cells  Help to fight disease - antibodies

51. Copyright Pearson Prentice Hall Chemical Reactions A chemical reaction is a process that changes one set of chemicals into another set of chemicals.

52. Copyright Pearson Prentice Hall Chemical Reactions The elements or compounds that enter into a chemical reaction are known as reactants. The elements or compounds produced by a chemical reaction are known as products.

53. Copyright Pearson Prentice Hall Energy in Reactions When hydrogen gas reacts with oxygen to produce water vapor, it is an energy-releasing reaction in which energy is given off as heat. 2H 2 + O 2 2H 2 O How would you reverse this reaction?

54. Copyright Pearson Prentice Hall Energy in Reactions Activation Energy Chemists call the energy that is needed to get a reaction started the activation energy.

55. Copyright Pearson Prentice Hall Enzymes Some chemical reactions that make life possible are too slow or have activation energies. These chemical reactions are made possible by catalysts.

56. Copyright Pearson Prentice Hall Enzymes Enzymes speed up chemical reactions that take place in cells.

57. Copyright Pearson Prentice Hall Enzyme Action The Enzyme-Substrate Complex Enzymes provide a site where reactants can be brought together to react, reducing the energy needed for reaction. The reactants of enzyme-catalyzed reactions are known as substrates.

58. Copyright Pearson Prentice Hall Enzyme Action An Enzyme-Catalyzed Reaction

59. Copyright Pearson Prentice Hall Enzyme Action Regulation of Enzyme Activity Enzymes can be affected by any variable that influences a chemical reaction. pH values Changes in temperature Enzyme or substrate concentrations