I.
Chemical level
A. Basic definitions
1. matter – anything that occupies space and
has mass
2. element – basic unit of all matter (109 total)
a. 92 natural elements
b. 4 basic – H, C, O, N, -96% of human mass
 Ca, P -> 99% (3%)
 K, S, Cl, Mg, I, FE, (16 other)1% ->
100%
c. atomic structure
1. nucleus – p+ and n0 (inside)
e- - (outside)
2. #e- = #p+
d. atomic number is the number of protons
e. atomic mass =p+ + n0
f. electrons in energy levels – 2,8,18, etc…
1.electrons jump – light releases
2.atom – attempts to fill outer levels
(valence) and bonding is the result
3.bonding – sharing, or giving/ receiving
of valence electrons – chemical reaction
B. Molecule – 2 or more atoms chemically combined
C. Compound – combination of 2 or more elements
D. Bonding
1. ionic – giving or receiving of e- (bond)
 transfer e- results in a change in charge
 ions – anions, cation
 electrolytes – ionic solution
2. covalent - more common in human body
 more stable
 sharing of e-, 1-4 pair H2, H2O, CO2, O2,
N2
a. H, O, N, C
3. Hydrogen bond – a hydrogen atom
covalently bonded to one O or one N
 H – O or H – N – may also be attracted to
other O or H
 Weak bridges between molecules
a. only 5% as strong as a covalent
bond
b. break and form easily
c. found in H2O, proteins, and
nucleic acids
E. synthesis reaction – anabolic (anabolism)
 A + B AB
(reactants) (products)
amino acids proteins
*energy required
F. decomposition – catabolism
AB A + B
 breakdown of food
 energy released
G. exchange (replacement) – single or double
replacement
AB + C  AC + B
AB + CD  AD + CB
II. Chemical compounds and life processes
A. inorganic compounds– usually lack carbon –
small
1. H2O – most abundant inorganic substance in
a human
a. 60% red blood cells
b. 75% muscle
c. 92% plasma
d. solvent – universal – liquid or gas that
something dissolves into
e. absorbs and releases heat slowly –
maintains homeostasis
f. lubricant – saliva, mucous
g. suspension medium
2. acids – dissociates into H+ and an anion
3. bases – dissociates into OH- and a cation
4. salts – ionize to form anions and cations
NaCl Na+ + Cl5. pH – degree of acidity or alkalinity of a soln
H+ > more acidic
OH- > more basic
a. pH scale – 0-14
0------------------7----------------14
many H+
neutral
many OHfew OHfew H+
acidic
basic
6. buffer system – maintains the body’s pH by
replacing strong acids and bases with weak
acids and bases
D. Organic compounds – always contain carbon –
covalent
1. Carbohydrate – C:H:O =1:2:1 ratio
a. sugars –
1. monosaccharide (3-7 carbons)
glucose, fructose, ribose, and
pentose (deoxyribose)
2. disaccharides – sucrose
 dehydration synthesis of 2
monosaccharides (H2O stripped)
b. starches
1. polysaccharides – starch, glycogen
 broken by hydrolysis
2. Lipids (fats) – C, H, O, - no fixed ratio and
most are not water soluable
a.two basic components are glycerol and
fatty acids
b. harder to break down than carbons but
actually provide 2x the energy of carbo’s
or protein
c. saturated, unsaturated, polyunsaturated
o saturated – single control bonds between
carbons – all C are bonded to a
maximum number of H
 beef, pork, butter, whole milk, eggs
and cheese
 the liver produces cholesterol from
the breakdown of sat. fats
o monounsaturated - 1 double covalent
bond between C
 olive oil, peanut oil
 help reduce cholesterol
o polyunsaturated – more than 1 double
covalent bond
 corn oil, safflower oil, sunflower
oil, cottonseed oil, sesame oil,
soybean oil
 help reduce cholesterol
3.Proteins - C, H, O, N
 body structure, physiological
activities ( catalysts)
 amino acids – 20 different and are
the building blocks
- amino group NH2
- carboxyl group COOH
- side chain – R group
 peptide bonds
- dipeptide – two amino acids
- tripeptide – three
- polypeptides – more than three
4. Nucleic acids – large organic molecules - C,
H, O, and P
 DNA – double helix - nitrogenous
bases, pentose, and phosphate
1000 rungs of a DNA form a gene
 RNA – single strand
5. Enzymes – normal body temp and
pressure are too low for chemical reactions
to occur rapidly enough
 enzymes are regulators (catalysts)
 specificity – specific - substrates –
molecule on which enzymes react
1. efficiency
2. control
6. ATP – energy – short term molecule
adenine + sugar + phosphate