Chemistry of Life
(1-1/2 lectures)
I.
Review
Living things:
1.
2.
3.
4.
5.
6.
II.
Are organized
Metabolize
Respond
Reproduce & develop
Adapt
At base: series of chemical reactions
Chemistry of Life
A. Both living & non-living (All matter):
1. Composed of elements
2. Obey chemical & physical properties
B.
Living things - 92 natural elements, 6 make up most of life (98% of all
biomass).
C - Carbon
H - Hydrogen
N - Nitrogen
O - Oxygen
P - Phosphorous
S – Sulfur
C.
Chemical structure
1. Atom: valence electrons
2. Molecule= more than 1 atom
D.
Chemical bonds
1. Ionic - transferred from one atom to another
2. Covalent Bond - More stable, atoms share "e-" equally
3. Polar molecule
a.
All ionic bonds
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b.
E.
Covalent bonds w/unequal sharing
Inorganic molecules (elements & compounds)
1. Usually ionic bonding
2. Always small number of atoms
3. Often associated with non-living
4. Water H2O
a.
Most important inorganic molecule in life
b.
Neutral pH = 7
< 7 = acid {more hydrogen (H+) ions}
> 7 = base {more hydroxide (OH-) ions}
pH 7  pH6 = 10x the acidity (10-7 H+)  (10-6 H+)
Most life prefers neutral
F.
Organic molecules {always compounds of carbon, but not the oxides of
carbon (CO2) or the carbonates (CO3)}
1. Structure
a.
Always covalent bonding
b.
May be large
c.
Usually associated with living
d.
Readily form in reduction reactions (addition of e- to
substrate) seldom form in oxidation reaction (removal of efrom substrate)
2. Carbohydrates
a.
(CH2O)x
b.
Glucose C6H12O6 - main energy source for most organisms
c.
Chains of glucose
i.
Starch
ii. Glycogen
iii. Cellulose
3. Lipids
a.
Neutral fat = 1 glycerol + 3 fatty acids (energy source if
needed)
i.
Saturated fatty acid
ii. Unsaturated fatty acid
b.
Phospholipids (cell membranes)
c.
Steroids (hormones)
d.
Waxes
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4. Proteins
a.
Amino acid chains
b.
Functions
i.
Enzymes
combination unique to species/individual
ii. Muscle fiber
collagen: most common protein in animals
iii. Cell membrane

Transport (channel and carrier) proteins
facilitates passage of H20 soluble molecules

Receptor proteins
bind w/hormones, etc.

Enzymatic membrane proteins

Adhesion
helps cells stick together to hold tissue shape

Recognition
unique to species/individual
5. Nucleotides - P + sugar + N base
a.
ATP (Adenosine Tri-phosphate)
energy = cell metabolism
i. "Kick start" metabolic reactions
ii. Muscle contractions
iii. Nerve impulses
b.
Nucleic acids
DNA=deoxyribonucleic acid (double helix)
Contains genetic code (made up of genes)
Unique to species/individual
RNA=ribonucleic acid (single chain)
carries genetic code from DNA to site of protein synthesis
(ribosomes)
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c.
Chemical Fingerprints
Order Primates
Superfamily Hominoidea (apes & man)
Families as presently classified:
i. Gibbons
ii. Orangutans
Gorillas
Chimpanzees
iii. Hominidae (extinct & Homo sapiens)
Families classified according to DNA nucleotide sequences in
genes; amino acid sequences in proteins; and immunization data:
i. Gibbons
ii. Orangutans
iii. Gorillas
Chimpanzees
Hominidae (extinct & Homo sapiens)
(18 of man’s 23 chromosome pairs are nearly
identical to those of Gorillas and Chimps. The
other 5 differ at inverted and translocated regions.
Chimps and man share 99% of their DNA)
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