Glossary of Terms
Alleles - Different forms of the
Base - One of the four different
chemical units which comprise DNA. The sequence of DNA bases codes
for the amino acid sequence of proteins. These four bases are: adenine,
cytosine, guanine, thymine, in DNA and RNA, uracil substitutes for
Biotechnology - The development
of a product or products using biological agents.
Chromosomes - Tiny thread-like
structures inside each cell. Chromosomes carry the genes.
Co-dominance - A circumstance
where the two alleles (or genes) for a specific trait are equally
strong: a mixture of the two phenotypes results: An example is pink
snapdragons develop from a red and white cross.
Crossing Over - The process in
which genes are exchanged between two chromosomes.
DNA (deoxyribonucleic acid) -
The substance within the chromosomes that carries the hereditary
instructions for producing proteins and RNA's.
Dominant - A gene or allele that
is expressed or "shown" in the phenotype. Dominant genes mask or
"hide" recessive genes.
Genes - Tiny biochemical structures
inside each cell that determine particular hereditary traits, such
as eye color and blood type. Each gene is a segment of DNA that
carries instructions for producing the chainlike molecules that
make up proteins.
Gene expression - The process
by which a cell makes a protein from RNA according to the instructions
carried by a gene.
Genetic variation - Refers to
the differences in inherited traits that exist among the members
of a species.
Genetics - The scientific study
Genome - A set of all the genes
a species has on its chromosomes. The human genome consists of 50,000
to 100,000 genes.
Genotype - The underlying genetic
makeup of a trait or the overall genetic makeup of an individual.
It is the two genes an individual carries for a trait.
Heredity - The passing of genetic
traits from parent to offspring.
Heterozygous - Two different alleles
for the same trait.
Homozygous - Only one allele is present for a particular
trait. Both genes are identical.
Hybrid - An organism that has
heterozygous alleles (or genes) for one or more traits.
Meiosis - Reproduction in sex
cells where the daughter cells produced have half the number of
Mendel, Gregor - So-called "father
of modern genetics". Austrian monk who discovered how genetic "factors"
were passed down.
Mitosis - Reproduction of non-sex
cells where the daughter cells produced have the same number of
chromosomes as the parent cells.
Mutation - A change in a gene.
It may produce a new trait that can be inherited.
Phenotype - The observable appearance
of a trait or the overall appearance of an individual.
Protein - Chemical building blocks
in the body made of smaller units called amino acids. Proteins exist
in every cell.
Recessive - An allele or gene
that is not expressed or "shown" in the phenotype because it is
"hidden" by the dominant gene.
RNA (ribonucleic acid) - Similar
to DNA, it plays a key role in the production of proteins.
Trait - A physical characteristic,
such as hair color