1. AP Biology Summer Reading
Chapter 2
Chapter 3
Chapter 4

2. Chemical Context of Life
Matter- how would you define it???
Element/Compounds
What’s the difference?

3. Chemical Context of Life
The atom- composed of:
Atomic number:
Mass number:
Isotopes:
Radioactive isotopes:
Atomic notation:

4. Chemical Context of Life
Energy (definition from physics):
Energy levels:
How many energy levels are found on the periodic table:
Valence electrons:

5. Chemical Bonding Covalent Double covalent Nonpolar covalent
Ionic
Hydrogen
van der Waals

6. Covalent Bonding Sharing pair of valence electrons
Number of electrons required to complete an atom’s valence shell determines how many bonds will form
Ex: Hydrogen & oxygen bonding in water; methane

7. Polar/nonpolar covalent bonds
Electronegativity attraction for electrons
Nonpolar covalent •electrons shared equally •Ex: diatomic H and O
Polar covalent •one atom more electronegative than the other (charged) •Ex: water

8. Polar/nonpolar bonds

9. Ionic bonding
High electronegativity difference strips valence electrons away from another atom
Electron transfer creates ions (charged atoms)
Cation (positive ion); anion (negative ion)
Ex: Salts (sodium chloride)

10. Hydrogen bonds
Hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom (oxygen or nitrogen)

11. van der Waals interactions
Weak interactions between molecules or parts of molecules that are brought about by localized charge 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

12. Water: Why is it important?
Creates environment suitable for life
Necessary for many biological and chemical processes

13. Water as a polar molecule:
Polar- opposite ends, opposite charges
Oxygen is more electronegative than hydrogen
Partial charges result
Gives water many distinct properties

14. Properties of Water: Cohesion- H+ bonds holding molecules together
Adhesion- H+ bonds holding molecules to another substance
Examples: water transportation in plants- flowing against the force of gravity (adhesion also)

15. Properties of Water:
Surface tension- measurement of the difficulty to break or stretch the surface of a liquid
Gives rain drops their tear- drop shape
Result of Cohesion

16. Properties of Water:
Water has a relatively high specific heat capacity
Specific heat- amount of heat required to raise the temperature of 1g. of a substance 10C.
Hydrogen bonds contribute to this property

17. Properties of Water:
Heat of vaporization- quantity of heat required to convert 1g from liquid to gas states
Why is this important?

18. Density Water is a dense substance: D= 1g/mL Due to hydrogen bonding
At what temperature is water its most dense?
What happens to the density as water approaches 00C?

19. Acid/Base & pH
Dissociation 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: substances that minimize H+ and OH- concentrations (accepts or donates H+ ions)

20. The molar mass of table sugar is ???
(C12H22O11)
How would you make a sugar water solution with a 1M concentration?

21. Organic chemistry Carbon: tetravalence
Tetrahedron: shape determines function

22. Carbon based molecules
Organic Chemistry:
Carbon based molecules
Tetravalence- carbon has four valance electrons (4 covalent bonds)
High energy storage
Diverse Molecules:
hydrocarbons

23. same molecular formula, but different structure & properties
Isomers:
same molecular formula, but different structure & properties

24. Isomers:
Structural-differing covalent bonding arrangement (straight vs. branched)
Geometric-differing spatial arrangement
Enantiomers-mirror images pharmacological industry

26. Functional Groups, I
Attachments that replace one or more of the hydrogen bonded to the carbon skeleton of the hydrocarbon
Each has a unique property from one organic compound to another

27. Functional Groups: Hydroxyl Group (-OH): oxygen bonded to hydrogen
Alcohols
Polar

28. Functional Groups: Carbonyl (C=O): carbon atom double bonded to oxygen
Keytones and Aldehydes
Polar

29. Functional Groups:
Carboxyl Group (O=C-OH): oxygen double bonded to carbon bonded to a hydroxyl
Polar
Releases H+ ion- forms acids

30. Functional Groups:
Amino Group (-NH2): nitrogen bonded to two hydrogen (Amino acids also contain carboxylic acids)
amines
acts as base

31. Functional Groups, II
Sulfhydryl Group (C-SH) or (R- SH): carbon bonded to sulfur bonded to H
Thiols
Sulfur analogue of alcohols (sulfur takes the place of oxygen:

32. Functional Groups: Phosphate Group (-PO42-):
phosphate ion
one oxygen is bonded to a carbon skeleton
polar

33. Biological thought:
Vitalism (life force outside physical & chemical laws) Berzelius
Mechanism (all natural phenomena are governed by physical & chemical laws) Miller