Page 414 - Carrahers_Polymer_Chemistry,_Eighth_Edition

Naturally Occurring Polymers—Animals 377

Exon: Segment of an eukaryotic gene that encodes a portion of the final product of the gene;

part that remains after posttranscriptional processing and is transcribed into a protein or
incorporated into the structure of an RNA. Also see intron.
Fibrillar protein: Hair like, insoluble, intermolecularly hydrogen-bonded protein.
Fibrils: Thread-like strands or bundles of fi bers.
Gene: Chromosomal segment that codes for a single functional polypeptide or RNA chain.
Gene expression: Transcription, and in for proteins, translation, giving the product of a gene;
a gene is expressed within its biological product is present and active.
Gene splicing: Enzymatic attachment of one gene or part of a gene to another.
Genetic code: Set of triplet code words in DNA or mRNA coding for the specific amino acids

of proteins.
Genetic information: Information contained in a sequence of nucleotide bases in chromo-
somal DNA or RNA.
Genetic map: Diagram showing the relative sequence and position of specifi c genes within a
chromosome.
Genome: All of the genetic information encoded in a cell or virus.
Genotype: Genetic makeup of an organism as distinct from its physical characteristics.
Globular proteins: Proteins with an overall globular structure formed from contributions of
secondary structures, including sheets and helices.
Glycine: Simplest and only nonchiral alpha-amino acid.
Immune response: Ability of a vertebrate to create antibodies to an antigen, a molecule typi-
cally a macromolecule, foreign to the host.
Inducer: Signal molecule that when attached to a regulatory protein, produces an increase
expression of a specifi c gene.
Intron: most genes are divided into two coding regions—one called exons or coding regions
and the second called intorns or noncoding regions.
In vitro: Literally means “in glass,” but today means outside the normal biological environment.
In vivo: Means “in life” and means within the normal biological environment.
Isoelectric point: pH at which an amino acid does not migrate to either the positive or negative
pole in a cell.
Keratin: Fibrillar protein.
Latex: Stable dispersion of polymer particles in water.
Myosin: Protein present in muscle.
N-terminal amino acid: Amino acid with an amino end group.
Nucleoside: Contains a pentose, and base.
Nucleotide: Contains a phosphate, pentose, and base.
Oligosaccharide: Low molecular weight polysaccharide.
Phenotype: The observable, physical characteristics of an organism.
Plasmid: Extrachromosomal, independently replicating, small circular DNA molecule often
used in genetic engineering.
Polynucleotide: Nucleic acid.
Polypeptide: Protein; often used for low molecular weight proteins.
Primer: Oligomeric molecule to which an enzyme adds additional monomeric subunits.
Probe: Labeled fragment of a nucleic acid containing a nucleotide sequence complementary
to a gene or genomic sequence that one wants to detect.
Prokaryotic cell: Bacteria single-celled organism with a single chromosome, no nuclear enve-
lope and no membrane-bounded organelles.
Primary structure: Term used to describe the primary configuration present in a protein

chain.
Prosthetic group: Nonprotenicious group conjugated (connected) to a protein.

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