CARBON COMPOUNDS - LECTURE NOTES
I. About Organic Compounds
1. Carbon can bond with a maximum of four other atoms. This allows carbon to
bond together in chains or rings.
2. An organic compound is made of molecules that have carbon backbones, often
arranged in a chain or a ring. Hydrogen, and many times oxygen, are also present
in organic compounds.
3. Organic compounds contain functional groups
Definition: Atoms or groups of atoms covalently bonded to a carbon
backbone; give organic molecules distinct properties.
1. Hydroxyl: 4. Amino:
3. Carboxyl: 5. Phosphate:
Question: What functional groups are in this molecule? Is it soluble in water? Can you identify
II. Synthesis/breakdown of Organic Molecules
Definition: A monomer is a small organic molecule that bonds with other monomers
to give a polymer.
Definition: The large molecules found in living things, made up of repeating smaller
C. Condensation (also called dehydration synthesis)
Definition: A chemical reaction in which two monomers become covalently bonded.
A hydrogen is removed from one monomer and a hydroxyl group is removed from
the other, giving off a molecule of water.
Definition: The reverse of condensation; occurs when a polymer is split into its
monomers by the addition of water.
III. The Organic Molecules of Life
Carbohydrates (also called saccharides; Greek for "sugar")
1. Definition: a simple sugar or larger molecule composed of sugar units.
2. Atoms of C, H, and O are always present.
3. Function: mainly energy sources.
4. Properties: sweet-tasting, soluble in water
a. Monosaccharides such as glucose (6-carbon sugar) – body ís primary energy
b. Oligosaccharides such as these disaccharides
sucrose (table sugar made of monomers of glucose and fructose)
lactose (milk sugar made of monomers of glucose and galactose)
maltose (grain sugar made of 2 monomers of glucose)
c. Polysaccharides such as
glycogen (storage form of glucose in animals)
starch (storage form of glucose in plants)
cellulose (structural form of glucose in plants)
1. Definition: A lipid is an oily, greasy, or waxy compound.
2. Atoms of C, H, O, and sometimes P.
3. Functions: Some are used for
a. energy storage
b. structural component of cell membranes
d. water repellent
4. Properties: insoluble in water (Why?)
5. Examples of lipids:
a. fatty acids which can be
saturated - single bonds only (solid at room temp.)
unsaturated - at least one double bond
polyunsaturated-at least 3 double bonds (liquid at room
b. triglycerides: fatty acids attached to glycerol
c. phospholipids: glycerol + 2 fatty acids + phosphate group
d. sterols: 4 fused carbon rings; ex: cholesterol
e. waxes: fatty acid chains + carbon rings
1. Definitions: A protein is a polymer of 21 possible amino acid monomers.
amino acid: organic compound having an amino group, an acid group, and a variable
2. Atoms of C, H, O, N, and sometimes S.
3. Functions: some are or provide
a. structure in living systems, e.g. bone, cartilage, muscles, hair, fingernails.
b. enzymes, which are biological catalysts (speed up reactions)
c. receptors on cells
d. transport of substances across cell membranes
e. transport of substances in body fluids;
EX: hemoglobin transports O2 in the blood
4. Protein Structure affects function.
a. primary structure: the sequence of the amino acids
b. secondary structure: coiled or pleated due to hydrogen bonding between atoms of
c. tertiary structure: 3-D shape due to reactions between R groups
d. quaternary structure: two or more 3-D polypeptide chains come together to form a
5. Protein denaturation - The loss of 3-D shape due to disruption of R group interaction;
deactivates function. The following can denature protein:
a. heating above 60 C
b. strong acids and bases
c. certain other chemicals
D. Nucleic Acids and their monomers
1. Definition: a polymer of nucleotides that carries the genetic instructions for
2. Atoms of C, H, O, N, and P.
3. Examples:DNA is double stranded; RNA is single stranded; sometimes nucleotides function
on their own - not as part of a nucleic acid; EX: ATP is the energy carrier for all cells.