1. Unit Overview – pages 138-139 The Life of a Cell The Chemistry of Life Atoms and Their Interactions

2. Element: a substance that can’t be broken down into simpler chemical substances. It is made of one type of atom. Section 6.1 Summary – pages 141-151 Elements Everything – whether it is a rock, frog, or flower – is made of substances called elements.

3. Section 6.1 Summary – pages 141-151 Of the naturally occurring elements on Earth, only about 25 are essential to living organisms. Carbon, hydrogen, oxygen, and nitrogen make up more than 96 percent of the mass of a human body. Natural elements in living things

4. Section 6.1 Summary – pages 141-151 Trace elements Trace elements such as iron and copper, play a vital role in maintaining healthy cells in all organisms. Plants obtain trace elements by absorbing them through their roots; animals get them from the foods they eat.

5. Section 6.1 Summary – pages 141-151 Table 6.1 Some Elements That Make Up the Human Body ElementSymbol Percent By Mass in Human Body Element Symbol Percent By Mass in Human Body Molybdenum Oxygen Carbon Hydrogen Nitrogen Calcium Phosphorus Potassium Sulfur Sodium Chlorine Magnesium Selenium Iron Zinc Copper Iodine Manganese Boron Chromium Cobalt Fluorine O C H N Ca P K S Na Cl Mg 65.0 18.5 9.5 3.3 1.5 1.0 0.4 0.3 0.2 0.1 Fe Zn Cu I Mn B Cr Mo Co Se F trace

6. Atom: the smallest particle of an element that has the characteristics of that element. Section 6.1 Summary – pages 141-151 Atoms: The Building Blocks of Elements Atoms are the basic building blocks of all matter.

7. contain positively charged particles called protons (p + ) particles with no charge, called neutrons (n 0 ). Nucleus: the center of an atom Section 6.1 Summary – pages 141-151 The structure of an atom Space surrounding the nucleus contains negatively charged particles called electrons (e - )

8. Section 6.1 Summary – pages 141-151 The Structure of an atom Nucleus Electron energy levels

9. Section 6.1 Summary – pages 141-151 The Structure of an atom Protons and neutrons are approximately the same size and mass, however electrons are far smaller Because opposites attract, the negatively charged electrons are held in the electron cloud by the positively charged nucleus.

10. Section 6.1 Summary – pages 141-151 Electron energy levels Electrons exist around the nucleus in regions known as energy levels. Nucleus 8 protons (p+) 8 neutrons (n 0 ) Oxygen atom First energy level can hold two e -. Second level can hold a maximum of eight e -. Third level can hold up to 18 e -.

11. Section 6.1 Summary – pages 141-151 Electron energy levels An atom of fluorine has nine electrons. How many electrons are in its second energy level?

12. Section 6.1 Summary – pages 141-151 Electron energy levels Atoms contain equal numbers of electrons and protons; therefore, they have no net charge. If an atom of fluorine has nine electrons, how many protons are in an atom of fluorine?

13. How many e - does phosphorous (P) have? How many p + does P have? How do you know?

14. Section 6.1 Summary – pages 141-151 Atoms of the same element always have the same number of protons but may contain different numbers of neutrons. Isotopes of an Element Isotopes: atoms of the same element that have different numbers of neutrons Carbon-12, carbon-13 and carbon-14 are examples of isotopes.

15. Section 6.1 Summary – pages 141-151 Compound: a substance that is composed two or more different elements that are chemically combined. Compounds and Bonding Table salt (NaCl) is a compound composed of the elements sodium and chlorine. Chemical formula Water (H 2 0) Hydrogen and Oxygen by themselves are flammable – together they are stable…

16. Section 6.1 Summary – pages 141-151 Atoms combine with other atoms to become more stable. Bonds: Types and how they form For many elements, an atom becomes stable when its outermost energy level is full. Sharing electrons with other atoms is one way for elements to become stable. Bonding is how they “share”

17. Section 6.1 Summary – pages 141-151 Covalent bond : an attractive force between two atoms that share electrons. Molecule : a group of atoms held together by covalent bonds. It has no overall charge. Water molecule

18. Section 6.1 Summary – pages 141-151 Two hydrogen atoms can combine with each other by sharing their electrons. How covalent bonds form Each atom becomes stable by sharing its electron with the other atom. Hydrogen molecule Think: full outer shell

19. Section 6.1 Summary – pages 141-151 An atom (or group of atoms) that gains or loses electrons and has an electrical charge and is called an ion. Ionic bonds Ionic bond : attractive force between two ions of opposite charge Example: A chlorine atom becomes a chloride ion when it gains an electron.

20. Hydrogen Bonds biological bonds Weak bonds (think magnet) between hydrogen (H + ) and oxygen (O - ). – Unequal sharing of electrons making it a polar molecule Hydrogen bonds give water unique properties

21. Hydrogen Bonds Unique properties of water due to H bonds: Universal solvent – Can bond with other water molecules and molecules of other substances Water has a greater resists to changes in temperature (boiling and feezing) Found in all 3 states: gas, a liquid, and a solid – Less dense when in a solid state Helps in temperature regulation of all organisms on earth

22. Section 6.1 Summary – pages 141-151 How are bonds and chemical reactions “related” ? Chemical reactions occur when bonds are formed or broken. causing substances to recombine into different substances (ex. burning paper). What do you think “Drives” all the breaking and forming of bonds? ENERGY!!! Bonds and Chemical Reactions

23. Section 6.1 Summary – pages 141-151 In a chemical reaction there are two parts: Reactants and Products chemical reactions

24. Section 6.1 Summary – pages 141-151 2H + O 2 = H 2 O - chemical equation of Water Chemical Reactions as Chemical Equations Chemical equations –Show bonds being broken and formed –They show the Law of Conservation of Mass (atoms are neither created nor destroyed in chemical reactions. They are simply rearranged.)

25. Mixture : a combination of substances in which the individual components retain their own properties. Section 6.1 Summary – pages 141-151 Mixtures and Solutions Neither component of the mixture changes. –Salad, chex mix, sand and water

26. Section 6.1 Summary – pages 141-151 Solution : a mixture in which one or more substances (solutes) are distributed evenly in another substance (solvent). Mixtures and Solutions Kool-aid, hot coco

27. Section 6.1 Summary – pages 141-151 Chemical reactions can occur only when conditions are right. Acids and bases A reaction may depend on: - energy availability - temperature - concentration of a substance - pH of the surrounding environment

28. Section 6.1 Summary – pages 141-151 pH : a measure of how acidic or basic a solution is. Acids and bases A scale with values ranging from below 0 to above 14 is used to measure pH. More acidic NeutralMore basic

29. Section 6.1 Summary – pages 141-151 pH below 7 are acidic. Acid : any substance that forms hydrogen ions (H + ) in water Acids and bases More acidicNeutral More basic

30. Section 6.1 Summary – pages 141-151 Substances with a pH above 7 are basic. Base : any substance that forms hydroxide ions (OH - ) in water. Acids and bases pH 11

31. Unit Overview – pages 138-139 The Life of a Cell The Chemistry of Life Organic Compounds: Macromolecules

32. 6.3 Section Summary 6.3 – pages 157-163 Carbon compounds that come from living organisms are called organic compounds. Two carbon atoms can form various types of covalent bonds—single, double or triple. The Role of Carbon in Organisms

33. 6.3 Section Summary 6.3 – pages 157-163 Molecular chains The small molecules, monomers, bond together to form large chains called polymers. Polymer : a large molecule formed when many smaller molecules bond together. Polymers usually form by covalent bonding.

34. There are 4 main organic compounds – Charbohydrates – Poteins – Lipids – Nucleic Acids

35. 6.3 Section Summary 6.3 – pages 157-163 Carbohydrate : composed of carbon, hydrogen, and oxygen with a ratio of about two hydrogen atoms and one oxygen atom for every carbon atom. The structure of carbohydrates

36. 6.3 Section Summary 6.3 – pages 157-163 Glucose and fructose combine in a condensation reaction to form sucrose (table sugar) Which is the reactant and which is the product? The structure of carbohydrates Monosaccharide : the simplest type of carbohydrate; a simple sugar (ie. glucose, fructose)

37. 6.3 Section Summary 6.3 – pages 157-163 The largest carbohydrate molecules are polysaccharides, composed of many monosaccharide subunits. (ie. potatoes, liver) The structure of carbohydrates Which is the monomer? Which is the polymer?

38. 6.3 Section Summary 6.3 – pages 157-163 Lipids : large biomolecules that are made mostly of carbon and hydrogen with a small amount of oxygen. (ie. fats, oils, waxes) The structure of lipids

39. 6.3 Section Summary 6.3 – pages 157-163 The structure of lipids They are insoluble in water because their molecules are nonpolar and hydrophobic (hydro) (phobic)

40. 6.3 Section Summary 6.3 – pages 157-163 A fatty acid with single bonds is saturated; with double bonds is unsaturated The structure of lipids

41. 6.3 Section Summary 6.3 – pages 157-163 Protein : a large, complex polymer composed of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. The structure of proteins

42. 6.3 Section Summary 6.3 – pages 157-163 The structure of proteins Amino acids : the basic building blocks of proteins There are about 20 common amino acids that can make literally thousands of proteins.

43. 6.3 Section Summary 6.3 – pages 157-163 Peptide bonds : covalent bonds formed between amino acids. The structure of proteins

44. 6.3 Section Summary 6.3 – pages 157-163 The structure of proteins Enzymes are important proteins found in living things. They speed the reactions in digestion of food. Proteins are the building blocks of many structural components of organisms.

45. The structure of proteins Enzyme : a protein that changes the rate of a chemical reaction. The sum of all the chemical reactions occurring in an organism is Metabolism

46. 6.3 Section Summary 6.3 – pages 157-163 Nucleic acid : a complex biomolecule that stores cellular information in the form of a code. The structure of nucleic acids Nucleotides : small subunits that make up nuclei acids

47. 6.3 Section Summary 6.3 – pages 157-163 The structure of nucleic acids Nucleotides are arranged in three groups—a nitrogenous base, a simple sugar, and a phosphate group. Phosphate Sugar Nitrogenous base

48. 6.3 Section Summary 6.3 – pages 157-163 DNA, which stands for deoxyribonucleic acid is a nucleic acid. The structure of nucleic acids Phosphate Sugar Nitrogenous base

49. 6.3 Section Summary 6.3 – pages 157-163 The structure of nucleic acids The information coded in DNA contains the instructions used to form all of an organism’s enzymes and structural proteins. Another important nucleic acid is RNA, which stands for ribonucleic acid. RNA is a nucleic acid that forms a copy of DNA for use in making proteins.