Download Organic Chem Biology

Organic Chemistry
Compounds that contain both
hydrogen and carbon are called
organic, the others are inorganic.
Organic Substances:
1. Carbohydrates
a.
Carbohydrates provide primary source
of energy for cellular activities and
are composed of carbon, hydrogen,
and oxygen.
b. Carbohydrates are made from
monosaccharides (simple sugars);
disaccharides are two monosaccharides
joined together;
complex carbohydrates polysaccharides),
such as starch, are built of many sugars.
2. Lipids:
a. Lipids are insoluble (waterproof) in
water and include fats (waxes and
oils), phospholipids, and steroids.
b. Fats supply long term energy
storage, are composed of oxygen,
carbon, and hydrogen, and are built
from glycerol and three fatty acids.
c.
Fatty acids with hydrogen at every
position along the carbon chain are
saturated; those with one or more
double bonds are called unsaturated
fats.
c. Phospholipids contain glycerol, two
fatty acids, and a phosphate group,
and are important in biological
membranes.
d. Steroids are complex ring
structures, and include cholesterol,
which is used to synthesize the sex
hormones (estrogen, progesterone,
testosterone).
• To form fats, glycerol and fatty acids bond.
3. Proteins:
a. Proteins have a great variety of
functions in the body---build tissues,
as certain hormones, as receptors on
cell membranes, as antibodies to fight
disease, and as enzymes to catalyze
metabolic reactions and cell
processes.
b. Proteins contain C, O, H, and
nitrogen atoms; some also contain
sulfur.
c. Building blocks of proteins are the
amino acids, each of which has a
carboxyl group, an amino group,
and a side chain called the R group.
d. The bonds between amino acids in
polypeptides are called peptide
bonds.
e. Proteins have complex shapes held
together by hydrogen bonds.
f. Protein shapes (conformation), which
determine how proteins function, can
be altered (denatured) by pH,
temperature, radiation, or chemicals.
• The bond between two amino acids is a
peptide bond; two bound amino acids
form a dipeptide, while many joined form
a polypeptide.
Denaturing
• When hydrogen bonds break in a protein as a
result of exposure to heat, radiation, pH
changes, or exposure to chemicals.
4. Nucleic Acids:
a. Nucleic acids form genes and
take part in protein synthesis.
b. They contain carbon, hydrogen,
oxygen, nitrogen, and phosphorus,
which are bound into building
blocks called nucleotides.
c. Nucleic acids are of two major
types: DNA (with deoxyribose)
and RNA (with ribose).
d.
RNA (ribonucleic acid) functions in
protein synthesis; DNA
(deoxyribonucleic acid) stores the
molecular code in genes.
Enzymes
A. Enzymes control the rates of all the
metabolic reactions of the cell.
B. Enzyme Action
1. Enzymes are complex proteins
that function to lower the activation
energy of a reaction so it may begin
and proceed more rapidly. Enzymes
are called catalysts.
2.
Enzymes work in small quantities and
are recycled by the cell.
3.
Each enzyme is specific, acting on only
one kind of substrate.
4.
Active sites on the enzyme combine
with the substrate and a reaction
occurs.
5.
The speed of enzymatic reactions
depends on the number of enzyme
and substrate molecules available.
• Enzymes are typically named for the
substrate and then end in –ASE
• Example: The enzyme that would work on
the substrate “sucrose” would be named
“sucrase”
C.
Factors That Alter Enzymes
1. Enzymes (proteins) can be denatured
by heat, pH extremes, chemicals,
electricity, radiation, and by other
causes.
Lock and Key Analogy