Exploring the Chemistry of Life: Atoms, Molecules, and Water Properties

1. Chemistry of Life Chapter 2 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 2.5 - Enzymes

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

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

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.

5. Sodium, reacts violently with water http://ruminatingdude.blogspot.com/2005/08/justifying-what-we-teach-in-hs.html Video Chlorine gas used in chemical warfare is Deadly stuff!

6. But chemically combined… 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) NaCl = Table salt!

7. 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. 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

9. 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?

10. _ _ O O H H H H + + + + 2.2 Properties of Water • 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. - Hydrogen bonds form between slightly positive hydrogen atoms and slightly negative atoms. KEY CONCEPTWater’s unique properties allow life to exist on Earth.

11. 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.

12. 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 polarand bonds with other water molecules it creates hydrogen bonds that create a small amount of tension on the surface. Properties of water video

13. solution 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. • homogeneous mixture. • Solventsdissolve other substances. • Solutesdissolve in a solvent.

14. bile pH between 8 and 9 stomach acid pH between 1 and 3 more basic more acidic 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

15. pure water pH 7 • A neutral solution has a pH of 7.

16. 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

17. 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

18. 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.

19. 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

20. 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 (C6H12O6) – glucose, fructose, galactose • Polysaccaharides • Glycogen, starches, and cellulose

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

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

23. 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 • Exampledisaccharide + water  monosaccharide +monosaccharide

24. 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.

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

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

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

28. Phospholipid • Phospholipids make up all cell membranes. • Polar phosphate “head” • Nonpolar fatty acid “tails”

29. 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.

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

31. 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.

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

33. Nucleic Acids • There are 2 types • DNA and RNA • DNA - stores the information for putting amino acids together to make proteins. • Deoxyribo Nucleic Acid • RNA – helps to build proteins. • Ribo Nucleic Acid

34. DNA RNA Nucleic Acids • DNA stores genetic information. • RNA builds proteins.

35. 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?

36. 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: changedduring a chemical reaction. • Products: madeby a chemical reaction. • Bondenergy - the amount of energy that it takes to break a bond. • Energy is added to break bonds. • Energy is released when bonds form. • A reaction is at equilibrium when reactants and products form at the same rate. CO2 + H2O H2CO3

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

38. Exothermic reactions release more energy than they absorb. • Reactants have higher bond energies than products. • Excess energy is released by the reaction.

39. 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.

40. 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?

41. 2.5 Enzymes • A catalyst lowers activation energy. • Catalysts are substances that speed up chemical reactions. • decrease activation energy • increase reaction rate

42. 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.

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

44. Substrates bind to anenzyme at certain places called active sites. The enzyme bringssubstrates together and weakens their bonds. The catalyzed reaction formsa product that is releasedfrom the enzyme. Enzymes • The lock-and-key model helps show how enzymes work. • substrates brought together • bonds in substrates weakened

45. 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?