pedigree The line of descent; a documented list or
table of ancestors, as in a genealogical record of an ani-
mal or person.
pelagic zone The ocean is divided into zones. The
whole mass of water is called the pelagic. This is divid-
ed into two major subzones: the neritic zone, which
covers all water to a depth of 600 feet, and the oceanic
zone, which covers all water below 600 feet. The
oceanic zone is further divided into subzones. The
mesopelagic (semidark waters) covers the depths from
650 feet to 3,200 feet, which is the middle layer
between the upper (sunlit 650 feet) epipelagic and the
lower (cold and dark) bathypelagic.
peptide bond The bond that links amino acids
together. Created by a condensation reaction between
the alpha-amino group of one amino acid and the
alpha-carboxyl group of another amino acid; a cova-
lent bond.
peptidoglycan A thick, rigid-layer, cross-linked
polysaccharide-peptide complex that is found in the
walls of bacteria. It is composed of an overlapping
lattice of two sugars, N-acetyl glucosamine (NAG)
and N-acetyl muramic acid (NAM), that are cross-
linked by amino acid bridges that are found only in
the cell walls of bacteria. This elaborate, covalently
cross-linked structure provides great strength of the
cell wall.peptidomimetic A compound containing nonpep-
tidic structural elements that is capable of mimicking or
antagonizing the biological action(s) of a natural par-
ent peptide. A peptidomimetic no longer has classical
peptide characteristics, such as enzymatically scissille
peptidic bonds.
See alsoPEPTOID.peptoid A PEPTIDOMIMETIC that results from the
oligomeric assembly of N-substituted glycines.262 pedigree
male affected male deceased malefemale affected female deceased femaleA simplified diagram of a family’s genealogy that shows family members’ relationships to each other and how a particular trait or
disease has been inherited.(Courtesy Darryl Leja, NHGRI, National Institutes of Health)