Chapter 2 Chemistry of Life

Transcription

1 Chapter 2 Chemistry of Life Section 2.1 Atoms, Ions and Molecules Section 2.2 Properties of water Section 2.3 Carbon-based Molecules Section 2.4 Chemical Reactions Section Enzymes 1

2 Atoms, Ions and Molecules Living things and non-living things are made of matter - Matter anything that occupies space and has mass - Mass the amount of matter in an object 2

3 Matter is made up of atoms. - Atom smallest particle of matter that can exist and still have the properties of that particular kind of matter. - 3 Parts make up an atom 1. proton positive charged particle Affects the IDENTITY of element 2. electron negative charged particle affects reactivity 3. neutron neutral/ no charge affects mass - Atoms make up elements 3

4 Atoms make up elements - Element substance consisting entirely of one type of atom. - Cannot be broken down into simpler substances. - Just 4 elements make up 96% of the human body s mass - Carbon (C) Nitrogen (N) - Oxygen (O) Hydrogen (H) - Elements are found on the periodic table. 4

5 Sodium, reacts violently with water Video Chlorine is very soluble in water and forms a strong acid when dissolved. The chemical symbol for chlorine is Cl. The formula for chlorine gas is Cl 2 Pacific Steel Chlorine Gas Leak Aug 2015 Chlorine gas used in chemical warfare is Deadly stuff! 5

6 But chemically combined NaCl = Table salt! Compound two or more elements that are chemically combined - Can be broken down into smaller substances Ex: water made up of hydrogen and oxygen = H2O NaCl - table salt (sodium and chlorine) 6

7 Contrast: How are elements different from compounds?

8 Ion - Is an atom that has gained or lost an electron, - Anion The atom gains an electron - Cation the atom loses an electron Ex. Li+ Ex. F- Ex. Ca+ Ex. O- 8

9 Apply: What determines whether an atom becomes a positive ion or a negative ion?

10 Compounds Ionic bond: Metal + Non metal (transferred electrons) Strongest bond Covalent bond: Nonmetal + nonmetal (shared electrons) Second strongest bond Molecule - The smallest part of a covalent compound that still has all the properties of the compound Example: the smallest unit possible of water 10

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12 Summarize: What happens to electrons in outer energy levels when two atoms form a covalent bond?

13 Checkpoint What distinguished one element from another? Describe how an ionic compound is formed and how a covalent compound is formed. What is the difference between and ionic bond and a covalent bond? 13

14 Chapter 2 Chemistry of Life Section 2.1 Atoms, Ions and Molecules Section 2.2 Properties of water Section 2.3 Carbon-based Molecules Section 2.4 Chemical Reactions Section Enzymes 14

15 2.2 Properties of Water KEY CONCEPT Water s unique properties allow life to exist on Earth. Life depends on hydrogen bonds in water. Water is a polar molecule. Polar molecules have slightly charged regions. Nonpolar molecules do not have charged regions. H H Hydrogen bonds form between slightly positive hydrogen atoms and slightly negative atoms. O _ H + _ O H + 15

16 Properties of water 1. High Specific Heat- water resists changes in temperature. Example: Ocean Temp 2. Cohesion Attraction of molecules of the same substance. 1 molecule of water sticking to another molecule of water (droplets) 3. Adhesion Attraction of molecules of different substances. Water molecules sticking to other things. Water sticking to glass. Water sticking to the inside stem of a plant. 16

17 Hydrogen bonds are responsible for four important properties of water. 1. Polarity 2. High specific heat 3. Cohesion 4. Adhesion Two additional properties of water: 5. Capillary Action - the ability to move upward against gravity. Due to the combined properties of adhesion and cohesion. 6. Surface Tension - because water is polar and bonds with other water molecules it creates hydrogen bonds that create a small amount of tension on the surface. Properties of water video (3:52 min) 17

18 Compare: How are hydrogen bonds similar to ionic bonds?

19 Many compounds dissolve in water. Like dissolves like. Polar solvents dissolve polar solutes. Nonpolar solvents dissolve nonpolar solutes. Polar substances and nonpolar substances generally remain separate. A solution - when one substance dissolves in another. solution homogeneous mixture. Solvents dissolve other substances. Solutes dissolve in a solvent. 19

20 Connect: What are the solvent and solutes in a beverage you drink?

21 Some compounds form acids or bases. An acid releases a hydrogen ion when it dissolves in water. high H + concentration ph less than 7 A base removes hydrogen ions from a solution. low H + concentration ph greater than 7 stomach acid ph between 1 and 3 bile ph between 8 and 9 more acidic more basic 21

22 A neutral solution has a ph of 7. pure water ph 7 22

23 Apply: Cells have higher H+ concentrations than blood. Which has a higher ph? WHY?

24 Check Point How do polar molecules form hydrogen bonds? What determines whether or not a compound will dissolve in water? Compare acids and bases Name one example, from everyday life, of adhesion and cohesion. Hank water video (11:17 min) 24

25 Chapter 2 Chemistry of Life Section 2.1 Atoms, Ions and Molecules Section 2.2 Properties of water Section 2.3 Carbon-based Molecules Section 2.4 Chemical Reactions Section Enzymes 25

26 The Necessities/ Chemistry of Life: CARBON All organisms must breakdown their food to use the nutrients found in it. Nutrients are made of molecules C, H, O, P, Ca, N, S the 7 main elements that make up living things. Carbon Hydrogen Oxygen Phosphorus Calcium Nitrogen Sulfur

27 2-3 Carbon Based Molecules- Organic Carbon atoms have unique bonding properties. Carbon forms covalent bonds with up to four other atoms, including other carbon atoms. Carbon-based molecules have three general types of structures. Straight chain, branched or rings 27

28 The Chemistry Of Life. CARBON Carbon Based Molecules Most molecules that make up living things are based on carbon atoms Carbon can form up to 4 covalent bonds (shared) There are 3 basic structures, because of Carbon s unique ability to form 4 covalent bonds. Straight chains and rings Branched chain Ring It is an important industrial chemical used as a monomer in the production of synthetic rubber a colorless pungent-smelling hydrocarbon gas, which burns with a bright flame, used in welding and formerly in lighting Benzene is a component of products derived from coal and petroleum and is found in gasoline and other fuels. Benzene is used in the manufacture of plastics It is the simplest alkane and the main component of natural gas. The relative abundance of methane on Earth makes it an attractive fuel, a liquid hydrocarbon present in petroleum. It serves as a standard in the system of octane numbers.

29 Carbon-Based Molecules Most Living things are made up of Carbon. (Organic) Many carbon-based molecules are made of many small subunits bonded together. Monomer = 1 molecule. Polymer = many monomers bonded together. 29

30 The Chemistry Of Life. CARBON Chains can bond with rings forming very large, very complex molecules. CONNECTING LOOPS and making CHAINS MONOMER the subunit in the completed molecule. POLYMER the large, or macromolecule made of many monomers bonded together.

31 The Chemistry Of Life. CARBON MONOMER that makes up a polymer, can be made of the same or different monomers. POLYMER can be called a MACROMOLECULE. (made from the same or different monomers).

32 Synthesize: Write your own analogy for the formation of a polymer from monomer.

33 The Necessities/ Chemistry of Life: CARBON Four Main Types of Carbon-based molecules Carbohydrates Lipids Proteins Nucleic acids All different structures All different functions All formed from carbon chains and rings

34 Four Main types of carbon based molecules 1. Carbohydrates Sugars and starches 2. Lipids Fats and oils 3. Nucleic Acids DNA and RNA 4. Proteins Amino acids 34

35 1. Carbohydrates Molecules made of C, H, O (1:2:1) Broken down into usable chemical energy that the body can use. Include sugars and starches Monosaccharides include simple sugars (C 6 H 12 O 6 ) glucose, fructose Polysaccaharides Glycogen, starches, and cellulose 35

36 Carbohydrates - Function Carbohydrates can be broken down to provide energy for cells. Some carbohydrates are part of cell structure. Polymer (starch) Starch is a polymer of glucose monomers that often has a branched structure. Polymer (cellulose) monomer Cellulose is a polymer of glucose monomers that has a straight, rigid structure 36

37 Carbohydrates Polysaccharides: Glycogen storage in animals (glucose/sugar) Starches made and stored by plants. Cellulose makes up the cell wall of a plant - structure 37

38 The Necessities/ Chemistry of Life - FOOD Carbohydrates molecules made of sugars. simple sugars can bond together to make larger sugar molecules. polysaccharides are polymers of monosaccharides. MONOMER POLYMER EXAMPLE Glucose Carbohydrate Cellulose Makes up cell walls in plant cells Contain Carbon, Hydrogen, Oxygen in a 1:2:1 ratio

39 Biochemical Reactions - Dehydration Synthesis anabolic reaction - polymers are formed monomer + monomer polymer + water Example: monosaccharide + monosaccharide disaccharide + water Hydrolysis large molecules ( polymers) broken into simpler ones (monomers) polymer + water monomer + monomer Example disaccharide + water monosaccharide +monosaccharide

40 2. Lipids Molecules made of C, H, O no fixed ratio Store large amounts of chemical energy in organisms. Include fats, oils, waxes and cholesterol Fats found in foods such as meat and butter. Oil olive oil, peanut oil Cholesterol your body needs a certain amount to function but too much can cause problems. 40

41 Lipids Lipids are nonpolar molecules -fats, oils, and cholesterol. contain carbon chains called fatty acids. fatty acids bonded to glycerol. Triglyceride 41

42 Lipids: structure Fats and oils have different types of fatty acids. saturated fatty acids (single bonds) unsaturated fatty acids (at least one double bond 42

43 Lipids: Functions broken down as a source of energy make up cell membranes used to make hormones 43

44 Phospholipids make up all cell membranes. Polar phosphate head Nonpolar fatty acid tails Phospholipid 44

45 3. Protein Molecules made of C, H, O and N A protein is a polymer made of monomers called amino acids. Organisms use 20 different amino acids to build proteins. Your body makes 12 of the 20 amino acids. The rest come from foods you eat such as meat, beans and nuts. Proteins differ in the number and order of amino acids. 45

46 The Necessities/ Chemistry of Life - FOOD Proteins made from amino acids Our bodies make 12 of the 20 needed. The food we eat gives us the other 8 that are necessary Different number and/or order of amino acids produce different proteins. Hemoglobin (574 amino acids) helps blood transport oxygen. If one amino acid changes, the structure changes IT doesn t work properly! Red Blood cells (round vs sickled)

47 Proteins 20 different amino acids are used to build proteins in organisms. differ in side groups, or R groups. linked by peptide bonds. 47

48 Protein Protein is required by the body for the growth, maintenance and repair of all cells. Protein is a major component of all muscles, tissues and organs. Needed for metabolism, digestion and the transportation of nutrients and oxygen in the blood. The main nutrient that keeps our hair shiny and healthy, our nails strong, our skin fresh and glowing and our bones strong and healthy. 48

49 The Necessities/ Chemistry of Life - FOOD Proteins made from amino acids MONOMER POLYMER EXAMPLE Amino acids Protein Hemoglobin Muscle Contain carbon, hydrogen, oxygen, nitrogen and sometimes sulfur Hemoglobin is used to transport oxygen in the blood

50 4. Nucleic Acids Molecules made of C, H, O, N and P Nucleic acids are polymers, made from monomers called nucleotides. Nucleotides are made of a sugar, phosphate group, and a nitrogen base. A phosphate group nitrogen-containing molecule, called a base deoxyribose (sugar) 50

51 Nucleic Acids There are 2 types of Nucleic Acids DNA and RNA DNA - stores the information for putting amino acids together to make proteins. DeoxyriboNucleic Acid RNA helps to build proteins. RiboNucleic Acid 51

52 Each Nucleotide has a specific matched partner A T (Adenine) (Thymine) G C (Guanine) (Cytosine) In RNA A U (Adenine) (Uracil) 52

53 Nucleic Acids DNA stores genetic information. DNA RNA builds proteins. RNA 53

54 The Necessities/ Chemistry of Life - ATP Nucleic Acid MONOMER POLYMER EXAMPLE Nucleotide Nucleic Acids DNA RNA DNA is the blueprint/ code for the genetic information

55 Apply: What is the relationship between proteins and nucleic acids?

56 Check Point What is the relationship between a monomer and a polymer? How are nucleic acids and proteins polymers? How are carbohydrates and lipids similar? Different? How does the property of carbon account for the variety of organic compounds? 56

57 Chapter 2 Chemistry of Life Section 2.1 Atoms, Ions and Molecules Section 2.2 Properties of water Section 2.3 Carbon-based Molecules Section 2.4 Chemical Reactions Section Enzymes 57

58 2.4 Chemical Reactions Bonds break and form during chemical reactions. Chemical reactions change substances into different ones by breaking and forming chemical bonds. Reactants: changed during a chemical reaction. CO 2 + H 2 O H 2 CO 3 Products: made by a chemical reaction. CO 2 + H 2 O H 2 CO 3 58

59 2.4 Chemical Reactions Bond energy - the amount of energy that it takes to break a bond. Energy is added to break bonds. H 2 CO 3 CO 2 + H 2 O Energy is released when bonds form. CO 2 + H 2 O H 2 CO 3 A reaction is at equilibrium when reactants and products form at the same rate. 59

60 Carbonic acid is a weak acid that is created when carbon dioxide (CO2) is dissolved in water (H2O), resulting in the chemical formula H 2 CO 3 It gives carbonated beverages their sharp taste. 60

61 Apply: Explain why concentration is important in a chemical reaction.

62 Chemical reactions release or absorb energy. Activation energy - amount of energy needed to start a chemical reaction. 62

63 Exothermic reactions release more energy than they absorb. Reactants have higher bond energies than products. Excess energy is released by the reaction. Endothermic reactions cause the surroundings to feel warmer 63

64 Endothermic reactions absorb more energy than they release. Reactants have lower bond energies than products. Energy is absorbed by the reaction to make up the difference. Endothermic reactions cause the surroundings to feel cooler 64

65 Analyze: How is activation energy related to bond energy?

66 Check point Hydrogen peroxide breaks down into water and hydrogen gas. Explain why this is a chemical reaction. What are the reactants? What are the products? How do endothermic and exothermic reactions differ? 66

67 Chapter 2 Chemistry of Life Section 2.1 Atoms, Ions and Molecules Section 2.2 Properties of water Section 2.3 Carbon-based Molecules Section 2.4 Chemical Reactions Section Enzymes 67

68 2.5 Enzymes A catalyst lowers activation energy. Catalysts are substances that speed up chemical reactions. decrease activation energy increase reaction rate 68

69 Summarize: Describe two functions of catalysts in chemical reactions.

70 Enzymes Enzymes allow chemical reactions to occur under tightly controlled conditions. Enzymes are catalysts in living things. Enzymes are needed for almost all processes. Most enzymes are proteins. 70

71 Enzymes An enzyme s structure allows only certain reactants to bind to the enzyme. Substrates - reactant active site substrates (reactants) enzyme Substrates bind to an enzyme at certain places called active sites. 71

72 Enzymes The lock-and-key model helps show how enzymes work. substrates brought together bonds in substrates weakened Substrates bind to an enzyme at certain places called active sites. The enzyme brings substrates together and weakens their bonds. The catalyzed reaction forms a product that is released from the enzyme. 72

73 Apply: How does the structure of an enzyme affect its function?

74 Check Point How does a catalyst affect the activation energy of a chemical reaction? Describe how the interaction between an enzyme and a substrate changes a chemical reaction Some organisms live in very hot or acidic environments. Would their enzymes work in a person s cells? 74