Exploring the Chemistry of Life: Atoms, Elements, and Organic Molecules

1. Chemistry of Life Chapter 2

2. How are living things (biotic) and non-living (abiotic) things different? • How are they the same? • All composed of Atoms

4. Element = substance that can’t be broken down into simpler chemical substances. • Represented by 1 or 2 letter code (H, O, Na, Cl, He, Ne…) • Made up of atoms Atoms = smallest particle of an element that has characteristics of that element.

5. Structure of an Atom • In the Nucleus: mass of the atom Protons (p+) – positive charge Neutrons (n0) – no charge (neutral) • In the Electron Cloud: space of atom Electrons (e-) – negative charge; in constant motion revolving around nucleus 7 different energy levels; each can only hold a set amount of electrons

7. IONS • Atoms or group of atoms with a positive or negative charge • Formed by loss or gain of electrons

8. Combination of Substances • Mixture: Physical combination of 2 or more things. Each substance keeps its original properties. • Compound: Chemical combination of 2 or more elements. The substances lose their original properties and form something new.

9. Bonding Combination of elements with electrons to become more stable Atoms want to have full outer e- level 2 e- in 1st level 8 e- in 2nd through 7th levels

10. Covalent Bonding: Sharing of electrons between atoms example: Water (H2O) • Ionic Bonding: Transferring of electrons between atoms Example: Table Salt (NaCl)

11. Chemical Reactions • forming or breaking of bonds between atoms • causes substances to combine and recombine to form molecules or compounds. • Occur only when conditions are right Metabolism = chemical reactions that occur over and over inside our cells

12. Measuring Acids and Bases • chemical reactions depend on how acidic or basic the environment is • Indicators = pH paper, litmus, and other substances that change color • pH = a measure of how acidic or basic a solution is. • Scale from 0 to 14 • 0 = strongest acid (lots of Hydrogen ions) • 7 = neutral • 14 = strongest base (few hydrogen ions)

13. ACIDS and BASES • Acids: • Sour taste (fruits) • forms hydrogen ions (H+) in water • abundance of H+ ions • pH below 7, the lower the pH the stronger the acid (Strong Acid = pH 1; Weak Acid = pH 6.9) • ex: HCl, H2SO4, HC2H3O2 …

14. Bases: • Bitter taste, slippery, good cleaners • forms hydroxide ions (OH-) in water • abundance of OH- ions • Has a pH above 7, higher the pH the stronger the base (Strong base = pH 14; Weak base = pH 7.1) • Ex: NaOH, NH3 …

15. Organic Molecules • Molecules involved in life • HONC 1234 = rule to describe most common organic elements and their bonding patterns. • H – hydrogen - 1 bond • O – oxygen – 2 bonds • N – Nitrogen – 3 bonds • C – carbon – 4 bonds

17. Role of Carbon in Organisms • Properties of Carbon: • Natures tinker toy • 4 electrons in outer shell • Forms 4 covalent bonds to become stable (single, double, or triple bonds) • Forms chains, branched chains, and rings

18. Image of carbon skeletons

19. Isomers • Molecules with same chemical formula, but different structural arrangements. • Each has different properties • Ex: Glucose and Fructose (C6H12O6)

20. Building Blocks • 50 common building blocks to carry out life’s functions • Monomer – small molecule building block of life • Ex: glucose • Polymer – molecule formed when monomers are linked together • Ex: cellulose is a polymer of glucose

21. Condensation and Hydrolysis Reactions

22. Condensation Reaction • Chemical reaction that occurs when monomers are linked together to form polymers. • Creates 1 water (H2O) molecule per link • Also called synthesis or dehydration

23. Hydrolysis Reaction • Chemical reaction that occurs when polymers are broken down into monomers • Addition of 1 water (H2O) for each broken link • Occurs during digestion, decomposition

24. Condensation and Hydrolysis Reactions

25. Carbohydrates Lipids Proteins Nucleic Acids These 4 groups of organic molecules, their monomers, polymers, and functions, are basic and essential to biology! Types of Organic Molecules

26. CARBOHYDRATES (starches and sugars) • Function– store energy for short term; sometimes used for structural support • Structure • Composed of C, H, and O • Ratio of 2 H for every 1 O • Monosaccharide – single sugar • Glucose (blood sugar), fructose (fruit sugar)

27. Disaccharide – two sugars • Sucrose (table sugar – glucose + fructose) • Polysaccharide – many sugars • Starch – storage in plants (potatoes) • Glycogen – storage in animal muscle and liver cells • Cellulose – fiber in plants (wood, paper)

29. LIPIDS (fats, oils, waxes, steroids) Functions: • Long term energy storage • Insulation, cushioning of organs • Waterproofing (waxes) • Chemical messengers in body (steroids)

30. Properties: • Composed of C, H, and O • Much less oxygen than carbon or hydrogen • Beef fat = C57H110O6 • Nonpolar – no net electrical charge • Insoluble in water

31. Triglycerides = type of fat • Composed of 3 fatty acids (monomers) and 1 glycerol (sugar) • Saturated fat = solid at room temp, lacks double bonds between carbons. • Unsaturated fat = liquid at room temp (oils), at least 1 double bond between carbon atoms somewhere in fatty acid chain

32. Triglyceride

33. Steroids • 4 connected carbon ring structures • Used as chemical messengers in body Ex: sex hormones (testosterone and estrogen) Phospholipids • Composed of 2 fatty acids, glycerol, and a phosphate group • Major component of cell membrane

34. A Steroid

35. Phospholipid

36. PROTIENS

37. Functions: • Structure – hair, finger nails, skin • Antibodies • Hormones • Movement – muscles • Enzymes – proteins that speed up chemical reactions in the body • 10,000 types of enzymes, each has a different function

38. Structure • Composed of C, H, O, N, and sometimes S • Made of monomers called amino acids (20 different types)

39. Amino acids consist of central carbon with the following attached • Hydrogen • Amine group, NH2 • Carboxyl group COOH • R-group – What makes the A.A. different from the rest. (R can be one of 20 different groups, from a simple H to a ringed structure) • Peptide Bond = covalent bond formed when amino acids link together to form proteins.

40. Polypeptide formation

41. NUCLEIC ACIDS(DNA and RNA) Structure • Composed of C, H, O, N, and P • Monomers = nucleotides • Sugar – ribose or deoxyribose • Phosphate group • Nitrogen Base – A, T, G, C, and U

42. Function: • Information Storage • Heredity – DNA is used to pass genetic info to next generation • Direct cell activities – RNA directs synthesis of proteins

43. Nucleotide

44. Double helix

45. Revisiting Enzymes: • 28 days to digest food without enzymes, only 2-4 hours with enzymes! • Catalyst - substance that speeds up chemical reactions w/o being consumed by the reaction (recycled) • substrate - molecule(s) going through chemical reaction • product -new molecule(s) formed after chemical reaction

46. active site - place on enzyme where substrate fits, like a hand in a glove. • substrate specific - each enzyme will only react with the substrate that fits the active site • denaturation - a change in the active site so it no longer reacts with the substrate, may be caused by extremes in temperature, pH, or toxins

47. Protein denaturation