1. Why Study Chemistry in Biology?

2. Ethylene gas ( hormone) stimulates the production of several enzymes
The enzyme that makes bananas sweet is called amylase. Amylase breaks down the starch in the banana fruit. When the starch is broken into its smaller sugar components, called glucose, the banana tastes sweet.

3. Prolong life by keeping warm temperatures - This is best explained by the banana’s slowed metabolic functions at a lower rate due to lower

4. I. Atoms Definition: smallest particle of an element
BOTH FOR LIVING AND NON LIVING
Definition: smallest particle of an element

6. B. Composition C. If Neutral Atom: # protons = # electrons Proton +1 1
Subatomic Particle
Charge
Mass
Location
Proton +1 1
Nucleus
Neutron
Electron -1
1/1840 the mass of a proton
Orbiting nucleus
C. If Neutral Atom: # protons = # electrons

7. II. Elements Definition: substance that cannot be broken
down into other substances
B. Biologically important elements
i. Major: C H O N
ii. Minor: Ca Fe Mg I Se P K Na Cl
Symbol: usually from first letter or two of full
name

9. Elements Con’t. Atomic Number: # of protons in nucleus
Mass Number
Atomic Mass amu
Atomic Number: # of protons in
nucleus
Backbone of life- 4 valence electrons make it easy to bond

10. E. Atomic Mass / Mass Number
Atomic mass: count of the total number of protons and neutrons in an atom's nucleus

11. F. Isotopes i. Definition: forms of the same element have same #
of protons but different # of
neutrons
Mass Number
ii. Radioactive isotopes: An isotope having an unstable
nucleus that decomposes
spontaneously

12. G. Chemical Compounds
i. Molecules definition: two or more atoms held together by COVALENT bonds

13. Compound definition: a substance containing two or more elements in a
fixed ratio
Ex: H2O, NaCl

14. Decoding Chemical Formulas??
C6H12O6
Element
subscript is the NUMBER of ATOMS
So in this molecule, there are 6 carbon atoms, 12 hydrogen, and 6 oxygen

15. 2H2O The number in front of H2O means two entire molecules of H2O
Think of it like 2 x (H20)
Sooooo… how many total atoms
of H are there?
Of oxygen?

16. III. Bonding happy Atoms want to fill their outer energy levels to be
In order to do this, they will meet up with other atoms and either share or exchange electrons
happy

17. A. Covalent Bonds
Atoms share electrons so that both atoms fill their outer energy level

18. B. Ionic Bonds: gimme that electron!
Atoms transfer electrons, becoming (+) or (-) charged
This attraction brings them together
Ex: Na and Cl

19. Ions
> An electrically charged atom

20. Carbon
Has 4 electrons in outer level, needs 4 more to fill its orbital
Hydrogen
Has 1 electron, needs 1 to fill its orbital
Can form ONE bond
Can form FOUR bonds

22. IV. Water Human Composition: 65–90% water Plant Composition: 80-90%
Formula: H2O
Bonds:
i. Hydrogen bonds: the slightly (+) H atoms
are attracted to nearby (-) O atoms, and
develop a weak bond.
ii. Covalent bonds: are shared between oxygen
and hydrogen in a single molecule.

23. V. Water (con.’t) Water is a polar molecule:
i. Definition of polarity: molecule
that has opposite electrical
charges on opposite ends
ii. Why? Oxygen does not share
electrons equally- pulls them closer
to itself, making it more negative
and Hydrogen more positive

24. V. Water (con.’t)
F. Unique molecule: i. Cohesion: 1. Definition: molecules of same kind stick to one another 2. Example: Surface tension; trees transporting water from roots to leaves

25. Adhesion:
1. Definition: attraction that occurs
between unlike molecules
2. Example: Water molecules and
cotton string.

26. Solutions:
1. Water is able to dissolve other polar and ionic compounds when mixed by causing the ions to break away and surround them.
Ex.: Salt Water

27. Suspensions
a. Definition: A heterogeneous mixture in
which particles settle out of solvent-like
phase some time after their introduction
b. Example: oil & water
iv. Boiling Point: water will boil at 100C or 212F

28. Acids and Bases
i. A water molecule can react to form ions
ii. An ion is when a molecule breaks down
and the atoms get a charge
1. Example: H+ and OH-

29. iii. pH Scale 1. How? Scale of 0-14; each pH unit represents a tenfold change in the concentration of H+ ions 2. Acid definition: pH Base definition: pH 8-14

30. 4. Buffer definition: substances that cause a solution to resist changes in pH.; works by accepting H+ ions when levels rise and donating H+ ions when levels fall, maintaining a constant pH a. Weak acid or base