1. Basic Chemistry
Biology

2. Matter Matter takes up space and has mass.
All matter (living and nonliving) is composed of basic elements.
Elements cannot be broken down to substances with different chemical or physical properties

3. CHNOPS Six elements are commonly found in living things. Carbon
Hydrogen
Nitrogen
Oxygen
Phosphorus
Sulfur
These elements account for about 98% of most organisms

4. Atoms, Molecules, Compounds
Atoms – smallest part of an element that retains the elements properties
Molecules – Groups of two or more atoms held together by Chemical Bonds
Compounds – Substance having two or more different elements chemically bonded together.

5. Protons and Neutrons are in nucleus of atoms; Electrons move around nucleus.
Protons are positively charged particles; Neutrons have no charge; both have about 1 atomic mass unit of weight.
Electrons are negatively charged particles

7. Protons,Neutrons & Electrons.ram

8. 2P=8e-
Octet Rule (outermost shell most stable with 8 electrons, if there’s more than one shell) Valence Shell
2S=8e-
1S=2e-

10. Isotopes
Isotopes are atoms with the same number of protons but differ in number of neutrons; thus a different atomic mass
e.g., a carbon atom has six protons but may have more or less than usual six neutrons.
Isotopes have many uses:
tracers of biochemical pathways;
determine age of fossils using radioactive isotopes;
radiation used in medical treatment

11. How Many Neutrons?

12. Molecular Formulas
Reactants
Products

13. What types of chemical bonds do we find in molecules?
Covalent- share electrons
Nonpolar covalent – electrons shared equally
Polar covalent - Electrons are shared unequally
Ionic- transfer of electrons
Hydrogen-weak bond between a partial positive and a partial negative.

14. Covalent Bond
2 atoms share electrons in such a way that each atom has an octet of electrons in the outer shell.
Single bond (H-H)
Double bond (O=O)
Triple bond (N N)

15. Electrons shared equally
Nonpolar Covalent Bonds
Electrons shared equally
Atoms with same electronegativity, usually diatomic molecules (ex. H2, O2, CH4)

16. Nonpolar Covalent Bonds

17. Polar Covalent Bonds Electrons are shared unequally
Has electronegativity.

18. Polar Covalent Bonds

19. Ionic Bonds
Electrons transferred from one atom to another. Losing or gaining electrons, atoms fill outer shells, and are more stable. Attraction of oppositely charged ions holds the two atoms together in an ionic bond.

20. Nonpolar Covalent Bonds
Ionic Bonds
Electrons Shared Equally
Electrons Shared Unequally
Electrons Transfered
Increasing difference of electro negativity between bonding atoms

21. Weak bonds BETWEEN molecules.
Hydrogen Bonds
Weak bonds BETWEEN molecules.
A hydrogen atom covalently bonded to one electronegative atom is attracted to another electronegative atom.

22. Hydrogen Bonds
Biologically important weak bonds helps stabilize 3 dimensional shape of large molecules(DNA and proteins).

24. What are the differences between: nonpolar covalent bonds
Chemical Bonds
What are the differences between:
nonpolar covalent bonds
polar covalent bonds
ionic bonds

25. Properties of Water High Specific Heat Capacity
High Heat of Vaporization
Good Solvent
Cohesion & Surface tension
Adhesion & capillary action
Ice Floats

26. Because water is polar molecule, it can form Hydrogen Bonds
Because water is polar molecule, it can form Hydrogen Bonds. Because of the Hydrogen Bonds, water has some very UNIQUE Properties!

27. The Chemistry of Water: Heat Capacity
Water has a high heat capacity
Temperature = rate of vibration of molecules
Apply heat to liquid
Molecules bounce faster
Increases temperature

28. Water has a high Specific Heat = the energy needed to heat 1g of a substance by 1°C. Very high for water b/c the H bonds must be broken; it takes a great deal of energy to heat or cool water.

29. The high specific heat of water is due to hydrogen bonds
The high specific heat of water is due to hydrogen bonds. Hydrogen bonds must be broken before water can evaporate. Evaporative cooling is why animals pant or sweat; it also stabilizes temperatures in ponds.

30. Evaporative cooling: when water evaporates, the heat is taken with it & the person (or solution) cools and their temperature decreases.

31. Water also has a high heat of vaporization, the amount of heat required to convert a liquid into a vapor without a change in temperature. This is due to the hydrogen bonds that must be overcome.

32. San Bernardino Burbank Santa Barbara 73° 100° 90° Riverside 96°
This property of water stabilizes temperatures of oceans, and is why coastal areas have moderate climates.
San Diego 72°
40 miles
Pacific Ocean
70s (°F)
80s
90s
100s
Santa Barbara 73°
Los Angeles
(Airport) 75°
Burbank
90°
San Bernardino
100°
Riverside 96°
Santa Ana
84°
Palm Springs
106°

33. Significance???
Because water temp rises and falls more slowly, organisms are better able to maintain their normal internal temperatures and are protected from rapid temperature change. Also moderates temperature on our planet.

34. The Chemistry of Water: 1. Good Solvent
Water facilitates chemical reactions both outside of and within living systems.
(Water is a good solvent – it dissolves other molecules because it is a polar molecule)

35. Hydrophobic -substances that do not dissolve in water (substances w/ nonpolar covalent bond)
Hydrophilic– substances that dissolve in water (substances w/ polar covalent bond)

36. In Cohesion, water has a tendency to cling to other water molecules
In Cohesion, water has a tendency to cling to other water molecules. Cohesion is due to hydrogen bonding.
Surface tension is how difficult it is to break the surface of a liquid. Due to cohesion.

37. In Adhesion, water has a tendency to cling to other substances
In Adhesion, water has a tendency to cling to other substances. Adhesion is also due to hydrogen bonding.

38. Cohesion
&
Adhesion

39. Ice is less dense than water due to hydrogen bonds forming a crystal
Ice is less dense than water due to hydrogen bonds forming a crystal. Most other solids are more dense than their liquids. The fact that ice floats means that lakes don’t freeze solid in winter.

40. Figure 2.12a
Figure 2.12

41. Water expands when it freezes
Hydrogen
bond
Ice
Hydrogen bonds are stable
Liquid water
Hydrogen bonds break and re-form

42. Figure 2.12b
Figure 2.12

43. Acids, bases, and pH
Acid molecules dissociate in water, releasing hydrogen ions (H+ ) ions
Bases are molecules that take up hydrogen ions or release hydroxide ions (OH-).
The pH scale indicates acidity and basicity (alkalinity) of a solution .

44. Figure 2.13
Figure 2.13

46. Buffers
Buffers stabilize pH of a solution by accepting or donating H+.
Organisms use buffers to maintain homeostasis.
Blood pH is 7.4
Carbonic Acid helps to maintain this pH