Why Study Chemistry in Biology?

1. Why Study Chemistry in Biology?

2. I. The Atom A. Definition: smallest particle of an element

3. B. Composition

4. Location of Electrons outermost electronsparticipate in BONDING

5. II. Elements A. Definition: substance that cannot be broken down into other substances B. Biologically important elements i. Major: C H O N P S (Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur)

6. Radioactive Isotopes

8. Bohr Atomic Model

9. Atoms Space

10. DO NOW • Why if atoms have so much space can we be solid?

13. III. Chemical Compounds A. Compound definition: a substance containing two or more elements in a fixed ratio • Ex: H2O, NaCl, CO2

14. B. Bonds: • Atoms want to fill their outer energy levels to be • To do this, they will meet up with other atoms and either or electrons complete exchange share

15. C o v a l e n t B o n d : 
s h a ri n g I s c a r I n g • Atoms shareelectrons

16. Examples of covalent molecules

17. ii. Ionic Bonds: gimme’ that electron! • Atoms transfer electrons, becoming (+) or (-) charged • The attraction brings them together • Ex: Na+ and Cl- = NaCl!

18. JOKE- Don’t Have to write this. • A NEUTRON walks into a diner and sits down to order a meal. • When the waitress brings the food over the neutron says “Can you bring the check? I am in a hurry!” • The waitress replies, “Don’t worry about it, there is NO CHARGE for you.”

19. JOKE- Don’t have to write this. • Two atoms walk down the street and collide. • One atom says to the other, “Are you okay?” • The second atom replies, “I think I lost an electron.” • The first atom says, “Are you sure?” • The second one says, “Yeah, I’m POSITIVE!”

21. iii. Molecules definition: two or more atoms held together by COVALENT bonds

22. V. WATER LIFE DEPENDS ON THE UNIQUE PROPERITIES OF WATER

24. Questions to think about • Why do put salt on the roads? • Why do we add salt to a pot of pasta water? • At a higher altitude why must we cook “boil” something longer?

25. Human Composition: Cells are 70–90% water

26. B. Plant Composition As much as 95% plants can be made of water

27. C. Formula: H2O

28. D. Bonds: i. Hydrogen bonds: Hydrogens from one water molecule are ATTRACTED to the oxygen of ANOTHER water molecule: they develop a weak bond

29. 1-inchpaperclip over-filled water 3oz Dixie cup i. Cohesion 1. Definition: Water “sticks” to each other Ex.: Surface tension

30. Jesus Christ Lizard

31. ii. Adhesion 1. Definition: Water molecules attracted to other molecules. 2. Ex. In trees/plants water goes against gravity Called capillary action

33. Water is the a Universal Solvent Water is able to dissolve other Polar &ionic compounds when mixed by causing the ions to break away and surround them. • Water dissolves Salt (Na+Cl-)

34. iii. Temperature and Water Boiling Point: 100 oC / 212 oF • When you heat molecules move faster • When you cool molecules move slower • Water takes more energy to heat because energy must break hydrogen bonds

35. Does water boil faster if you add salt to it? • Water Boils when it has enough energy for the molecules to leave

36. Freezing Point 0 oC or 32 oF • What would happen if our oceans did not have salt in them? • Why do we put salt on our roads? • Why at effect does salt have on FREEZING POINT?

37. Why is this important for life? Water Boiling Point Ethanol Boiling Point

38. Why are higher altitude must we cook “boil” something longer?

39. Why do we need salt in our ice, when making ice cream? Watch Video

40. LOW DENSITY OF ICE • Density- amount of matter in a volume • In most substances the solid state is more dense than the liquid state • Water is the opposite ICE IS LESS DENSE THAN WATER and will FLOAT

41. LOW DENSITY OF ICE • WHY? • Hydrogen bonds in ice (solid) keep molecules spaced out

42. LOW DENSITY OF ICE • Floats • Ice insulates the liquid water below allowing life to persist