Glossary of Scientific Terms

T

Taxonomy
Taxonomy is the classification of organisms according to their evolutionary relationship. Taxonomic groups are organized in a hierarchical fashion from the most inclusive domains of life (archaea, bacteria, eukarya, viridae) to the lowest most specific species description (e.g. Homo sapiens).

Teleological (teleology)
A way of arguing that natural systems have a way to look forward to improve their own situation. Teleological arguments are often found in evolutionary literature such as '... a plant becomes tastier in order to gratify the animal's needs and desires....' (see Pollan, 2008, In Defense of Food, p.102). Of course, plants to not plan on being tastier, but this 'tastiness' is the result of animals preferring this particular flavor increasing the seedling's chance to grow and have its own offspring.

Theory
A scientific theory is an established and experimentally verified fact or collection of facts about the world. Unlike the everyday use of the word theory, it is not an unproved idea, or just some theoretical speculation. The latter meaning of a 'theory' in science is called a hypothesis.

Thermodynamics
The physical theory of heat and energy distribution in the universe. The two important laws of thermodynamics state that the total energy of the universe is constant and energy can neither be made nor destroyed, and that the distribution of energy in the universe over time proceeds from a state of order to a state of disorder (entropy increase).

Trait
The physical or metabolic phenotype of an organism such as red flower color and length of stem in plants and black fur or pink eye in mice. See also phenotype and genotype.

Transcript, transcriptome
A transcript is an RNA copy of a DNA template, i.e., a ribonucleic acid copy of a gene. Transcripts are also known as messenger RNA and are the mediator between the gene and a protein product. The transcriptome is a term used to indicate the total set of transcripts found at any given time in a cell or organisms. The idea is that the presence of mRNA in a cell indicates the use of a gene. The type and number of active genes is an indicator of the actual metabolic and physiological state of a cell.

Transporter
A membrane protein that functions as an ion channel, solute transporter, facilitator or pump to move molecules across cell membranes.

Triglycerides
The constituent of fat composed of glycerol and three fatty acids. Most triglycerides are obtained from food as fats or synthesized by the liver and stored in liver and fat cells (adipocytes). Triglycerides are one of three major sources of metabolic fuel (the other sources are carbohydrates and proteins) providing energy for the physiological processes of the body.