The Basics of Chemistry for Biology

1. The Basics of Chemistry for Biology • Atoms: The units of elements • Bonding: Covalent vs. Ionic • Water: Water‘s unique properties

2. The Chemistry of Life • Matter • (anything that takes up space) • Composed of atoms • Atom • Smallest unit of an element that has the properties of the element • 2 regions • Nucleus • Electron cloud

3. Inside the Atom: Subatomic Particles • Protons: positive charged particles found in the nucleus (p+) • Neutrons: neutral particles found in the nucleus (nº) • Electrons: negative particles found in the electron cloud (e-) • Move around the nucleus in energy levels

4. Energy Levels of the Electron Cloud The number of electrons on each level is given by the formula 2n2 where n is the level number

6. Info from the Periodic Table • Symbol • Atomic Number (Z) • = Number of p+ • Mass Number (A) • = p+ + nº

7. Nuclides A ZX Copper Oxygen

8. Practice Set

9. Let’s Draw an Atom • Write the nuclide. • Draw the Energy levels. • Write the number of protons and neutrons in the nucleus. • Place the correct number of electrons on each energy level. • Leave unused energy levels empty.

10. Practice Drawing

11. Ions • For a neutral atom, protons = electrons • Ion: an atom with more or fewer electrons than it should normally have, causing a charge • Loss of electrons forms a positive ion • Cation • Gain of electrons forms a negative ion • Anion

12. Isotopes • Isotopes: atoms of the same element with different masses due to different # of neutrons • radioactive isotopes: unstable nuclei breakdown over time (nuclear decay)

13. Summary Chart

14. Bonding and Compounds • Compound: two or more atoms bonded together due to electron exchange (give & take) or electron sharing

15. Metals • Metals are found mainly in columns I to III • They give away electrons to bond • This forms positive ions: cations

16. Non-metals • Non-metals are found mainly in columns III to VIII • They can take in electrons from a metal to bond and form negative ions: anions • They can share electrons with another non-metal and form molecules

17. Ionic Bonding • Ionic Bonding: involves the giving of electrons by metals and the taking of electrons by non-metals • Examples • Sodium chloride • Calcium chloride • Sodium oxide • Forms IONS

18. Ionic bonding

19. Covalent Bonding • Covalent Bonding: the sharing of electrons between two non-metals • Carbon dioxide • Methane • Nitrogen dioxide • Diphosphorus pentoxide • Forms MOLECULES

20. Covalent Bonding

21. Polarity • Polar: electrons are not shared equally between the two non-metals in a covalent bond • Non-polar: electrons are shared equally between the two non-metals in a covalent bond

22. Polar covalent bond

23. Polar/nonpolar bonds

24. van der Waals forces • van der Waals forces: forces of attraction between molecules • Weak forces

25. van der Waals interactions • Weak interactions between molecules or parts of molecules that are brought about by localized change fluctuations • Due to the fact that electrons are constantly in motion and at any given instant, ever-changing “hot spots” of negative or positive charge may develop

26. Hydrogen bonds • Hydrogen atom covalently bonded to one atom is also attracted to another atom (oxygen or nitrogen) on another molecule • Strong • Water is best example

27. Cohesion • Cohesion: attraction of molecules of the same substance to each other • Example water molecules to other molecules in a glass

28. Water’s Properties • Polar~ opposite ends, opposite charges • Cohesion~ H+ bonds holding molecules together (same substance, water to water) • Adhesion~ H+ bonds holding molecules to another substance • Surface tension~ measurement of the difficulty to break or stretch the surface of a liquid • Specific heat~ amount of heat absorbed or lost to change temperature by 1oC • Heat of vaporization~ quantity of heat required to convert 1g from liquid to gas states • Density……….

29. Density • Less dense as solid than liquid • Due to hydrogen bonding • Crystalline lattice keeps molecules at a distance

30. Mixtures • Combination of 2 or more elements physically but not CHEMICALLY (not bonded together)

31. Wet Mixtures Soution Suspension Components are distributed unevenly, just mixed together Parts Supernant: liquid Precipitate: solid Example: snowglobe • All components are distributed evenly • Parts • Solute: is dissolved • Solvent: does the dissolving Example: Kool-aid dissolved in water

32. Acid/Base & pH • Dissociation (breaking apart) of water into a hydrogen ion and a hydroxide ion • Acid: increases the hydrogen concentration of a solution • Base: reduces the hydrogen ion concentration of a solution • pH: “power of hydrogen” • Buffers: weak acids or bases that react with strong acids or bases to prevent changes in pH

33. pH Scale Acid NeutralBase 0 1 2 3 4 5 6 78 9 10 1112 13 14 Stronger Weaker Weaker Stronger Human body prefers pH of 6.5 to 7.5

34. Acids vs. Bases Acid Base “Alkaline” More OH- than H+ Tastes bitter Turns litmus paper blue Found in cleaners and soaps • “Acidic” • More H+ than OH- • Tastes sour • Turns litmus paper red • Found in coffee, tea, soft drinks, and fruit juices

35. Neutralization When Acids and Bases are mixed chemically, they produce salt and water. This reaction is called neutralization because the end products are not acidic nor alkaline, they are neutral!

36. What are living creatures made of?Why do we have to eat? The Chemistry of Life

37. Elements of Life • 96% of living organisms is made of: • carbon (C) • oxygen (O) • hydrogen (H) • nitrogen (N)

38. Molecules of Life • Put C, H, O, N together in different ways to build living organisms • What are bodies made of? • carbohydrates • sugars & starches • proteins • fats (lipids) • nucleic acids • DNA, RNA

39. Why do we eat? • We eat to take in more of these chemicals • Food for building materials • to make more of us (cells) • for growth • for repair • Food to make energy • calories • to make ATP ATP

40. What do we need to eat? • Foods to give you more building blocks & more energy • for building & running bodies • carbohydrates • proteins • fats • nucleic acids • vitamins • minerals, salts • water

41. Don’t forgetwater • Water • 65% of your body is H2O • water is inorganic • doesn’t contain carbon • Rest of you is made of carbon molecules • organic molecules • carbohydrates • proteins • fats • nucleic acids

42. How do we make these molecules? How do we make these molecules? We build them! We build them!

43. How to take large molecules apart • Digestion • taking big molecules apart • getting raw materials • for synthesis & growth • making energy (ATP) • for synthesis, growth & everyday functions + ATP

44. Example of digestion ATP • Starch is digested to glucose ATP ATP ATP ATP ATP starch glucose ATP

45. Building large molecules of life • Chain together smaller molecules • building block molecules = monomers • Big molecules built from little molecules • polymers

46. Building large organic molecules • Small molecules = building blocks • Bond them together =polymers

47. amino acid amino acid amino acid amino acid amino acid amino acid – – – – – Building important polymers Carbohydrates = built from sugars sugar – sugar – sugar – sugar – sugar – sugar Proteins = built from amino acids Nucleic acids (DNA) = built from nucleotides nucleotide – nucleotide – nucleotide – nucleotide

48. How to build large molecules • Synthesis • building bigger molecules from smaller molecules • building cells & bodies • repair • growth • reproduction + ATP

49. How to take large molecules apart • Digestion • taking big molecules apart • getting raw materials • for synthesis & growth • making energy (ATP) • for synthesis, growth & everyday functions + ATP

50. Example of digestion ATP • Starch is digested to glucose ATP ATP ATP ATP ATP starch glucose ATP