CHAPTER 2 - THE CHEMICAL BASIS OF LIFE
I. BASIC CHEMISTRY
A. ELEMENTS - 92
1. CHNOPS = 99%
B. ATOMS - smallest "piece" of an element (Fig. 2.1, p. 25)
1. 3 subatomic particles:
Mass Charge
Nucleus PROTON 1 +
NEUTRON 1 0
ELECTRON 0 -
2. ATOMIC NUMBER = # PROTONS/ELECTRONS
3. ATOMIC MASS = # PROTONS + NEUTRONS
4. ISOTOPES - same atom, diff. # of neutrons (fig 2.3, p. 26)
5. ENERGY LEVELS/SHELLS/ORBITALS - electron arrangements
examples: a. 1H1
b. 4He2
c. 7Li3
d. 12C6
C. BONDS (Table 2.4 p. 31)
1. IONIC - lose/gain e-, strong in solids, weak in liquids (Fig. 2.4, p 27)
a. 23Na11 - explosive white metal
- 1 e- in outer shell
- wants to lose e- = Na+ = CATION
b. 35Cl17 - lethal green gas
- 7e- in outer shell
- wants to gain e- = CL- = ANION
c. NaCl = salt!
d. ELECTROLYTES = ions in solution
2. COVALENT - share e-, strongest, most common (Fig. 2.5, p. 28)
a. NONPOLAR - equal sharing of e-; CH4 - methane
b. POLAR - unequal sharing of e-; H2O (Fig. 2.6, p. 29)
3. HYDROGEN - weak, between atoms of polar cov. mole. (Fig. 2.7, p. 31)
H2O - - -H2O
II. CHEMICAL REACTIONS - interaction/rearrangement of bonds
- req. proper orientation of atoms & energy
- REACTANTS è PRODUCTS
A. CLASSIFICATION
1. SYNTHESIS A + B è AB Na+ + Cl- èNaCl
a. ANABOLISM = all synthesis rxns in body
b. DEHYD/CONDENSATION - produce H2O (Fig. 2.10a, p. 33)
2. DEGRADATION/DECOMPOSITION AB è A + B H2O è H+ + OH-
a. CATABOLISM = all degradation rxns in body
b. HYDROLYSIS – uses/splits H2O in rxn (Fig. 2.10b, p. 33)
3. EXCHANGE AB + CD è AD + BC NaOH + HCL è H2O + NaCl
4. REVERSIBLE CO2 + H2O çè H2CO3 çè H+ + HCO3-
5. REDOX RXNS - “LEO says GER”
B. RATE
1. ENZYMES = BIOLOGICAL CATALYSTS
2. TEMPERATURE
3. pH
4. AMOUNT OF REACTANTS
III. ENERGY - capacity to do work
- POTENTIAL - stored energy
- KINETIC - working energy
A. ELECTRICAL
1. movement of ions/e-
2. nerves & muscles
B. ELECTROMAGNETIC
1. WAVES
2. GammaèUVèVisibleèIR/HeatèMicroèRadio
C. CHEMICAL - interactions of e- between molecules
(Fig 2.11, p. 35)
ENDERGONIC (a) EXERGONIC (b)
1. Makes bonds 1. Breaks bonds
2. Stores/requires energy 2. Releases/liberates energy
3. ANABOLISM 3. CATABOLISM
CATABOLISM + ANABOLISM = METABOLISM
D. HEAT - produced by random movement
1. EXERGONIC rxns/CATABOLISM produces - body temp
E. MECHANICAL/KINETIC - movement
F. ENERGY TRANSFER - not efficient, lost as heat/light
1. ACTIVATION ENERGY - lowered by ENZYMES (Fig. 2.12, p. 36)
IV. INORGANIC MOLECULES - contain no C (except CO2, CO & HCO3-)
A. WATER
1. TEMP BUFFER
2. PROTECTION - lubricant, toxin removal
3. CHEMICAL RXNS - occur in water & with water
4. MIXING MEDIUM - solutions/suspensions/colloids
5. SOLVENT - water; SOLUTE - stuff dissolved in solvent = SOLUTION!
a. OSMOLALITY = # particles dissolved in solution
b. mOsm = units of measure in physiology
B. ACIDS & BASES - pH scale; measure of [H+]
1. ACID - donates H+, pH 1-6
2. BASE - accepts H+ (donates OH-), pH 8-14
3. NEUTRAL - pH 7, equal concentration of H+ & OH-
4. pH SCALE (Fig. 2.13, p. 39), 10X increase in each number
5. SALTS - cation other than H+, anion other than OH-
6. BUFFERS
a. resist change in pH, keep pH stable
b. donate or accept H+
c. CO2 + H2O çè H2CO3 çè H+ + HCO3-
C. OXYGEN - needed for aerobic respiration, energy breakdown
D. CO2 - released by aerobic respiration, energy breakdown
V. ORGANIC MOLECULES - contain C held together by covalent bonds
- 4 major macromolecules
- MONOMERS = building blocks
- POLYMERS = chains of building blocks
A. CARBOHYDRATES - SUGARS/SACCHARIDES, -ose (p. 40-42)
- ENERGY, STRUCTURE, BULK in feces
*1. MONOSACCHARIDES - single sugar: GLUCOSE, FRUCTOSE
- 3-7 C: PENTOSE(5), HEXOSE(6)
2. DISACCHARIDES - double sugars: SUCROSE
3. POLYSACCHARIDES - many sugars
a. PLANTS: STARCH, CELLULOSE, CHITIN
b. ANIMALS: GLYCOGEN
B. LIPIDS - FATS, OILS, WAXES, nonpolar, insol. in water
1. TRIACYLGLYCEROLS = GLYCEROL+ 3 FAT. ACIDS (p. 42-46)
2. SATURATED - F.A. hydrogenated, no C=C, animals & palm oil (p. 44)
3. UNSATURATED - C=C present, plants & fish
4. PHOSPHOLIPIDS (Fig. 2.18, p. 45)
5. CHOLESTEROL (Fig. 2.19, p. 45)
6. FXN- VIPERS (Tab. 2.7, p. 42)
VITAMINS (A,D,E,K) ENERGY
INSULATION REGULATION (HORMONES)
PROTECTION STRUCTURE (PHOSPHOLIPIDS)
C. PROTEINS - (p. 46-48)
*1. AMINO ACID - (20)
2. STRUCTURE a. 10, PEPTIDE BONDS join A.A.s into chain
(Fig. 2.22, p. 48) b. 20 - HELIX/SHEET
c. 30 - GLOBULAR, ENZYMES
d. 40 - 30's joined together, HEMOGLOBIN
4. FXN - CREPTS (Tab. 2.7, p. 46)
CONTRACTION (MUSCLE)
REGULATION (ENZYMES, HORMONES)
ENERGY
PROTECTION (ANTIBODIES)
TRANSPORT
STRUCTURE (COLLAGEN, KERATIN)
5. DENATURE - loss of fxn due to change in shape of enzyme
a. due to change in TEMP, pH, other chemicals
D. NUCLEIC ACIDS - (p. 49-52)
*1. NUCLEOTIDE a. 5-C MONOSACCHARIDE
(Fig. 2.24, p. 49) b. PHOSPHATE
c. NITROGENOUS BASE
i. PURINES: DOUBLE RINGS, A & G
ii. PYRIMIDINES: SINGLE RINGS, C & T/U
2. DNA - a. NUCLEUS - HEREDITARY INFO.
b. DOUBLE HELIX/STRAND
c. A=T; C=G
3. RNA - a. NUCLEUS & CYTOPLASM
b. SINGLE STRAND
c. A=U; C=G
4. ATP - a. ADENOSINE TRIPHOSPHATE (Fig. 2.27, p. 51)
b. ENERGY CURRENCY OF CELLS
c. 2,000,000 ATP/SEC/CELL AT REST !
d. 75 trillion cells in body --
150 X 1014 ATP used/sec in body ! ! !