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A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-W-X-Y-Z

T

T cell
Lymphocyte that matures within the thymus. The cells active in cell-mediated immunity are T cells. [Discussion] [CD4+ subset] [CD8+ subset] [Helper subsets (Th1 and Th2)]
TACO
tryptophan-aspartate coat protein
Taiga
The northern coniferous forest.
TAP
Transporter associated with antigen processing [More]
Taste
in humans
Taxis
Automatic locomotion of a motile organism in a direction determined by the direction from which the stimulus strikes the organism.
Taxol
Taxonomy
Classification of organisms.
TCDD
[dioxin]
TCR
T-cell receptor for antigen. [More] [gene segments]
Telomerase
Telomeres
Tendon
Teratogen
A substance that causes birth defects.
Teratoma
Tertiary structure
[Protein]
tesla
Unit of magnetic field strength. [More]
Test cross
Testosterone
Tetanus
Sustained maximal contraction of a muscle. [More]
Tetracycline antibiotics
Tetrad
(1) The duplicated homologous chromosomes held together by chiasmata prior to anaphase I of meiosis. Each tetrad contains four chromatids. [More] (2) The four products of meiosis kept together like the four spores in the ascus of budding yeast.
Thalamus
THC
delta-9-tetrahydrocannabinol
Thiamine
vitamin B1
Thick (and thin) filaments
of muscle
Thoracic duct
Threonine
[structure]
Threshold
Minimum intensity of a stimulus to which something responds. [of excitable cells]
Thrombin
Enzyme that converts fibrinogen to fibrin. [More]
Thrombocytopenic purpura, immune
Thrombopoietin
Liver hormone that stimulates platelet production. [More]
Thylakoid
A pair of chlorophyll-containing membranes that form disklike structures within chloroplasts. Stacks of thylakoids are called grana.[More]
Thymidine kinase
[More]
Thymine
[structure]
Thyroid-stimulating hormone (TSH)
Thyrotoxicosis
Graves' disease
Thyrotropin-releasing hormone (TRH)
Thyroxine
Tight Junctions
Tissue
Association of cells bound together by cell walls (plants) or extracellular matrix (animals) that performs particular functions.
Tissue typing
to determine histocompatibility
Tissue plasminogen activator (TPA)
Titin
[Size]
Tocopherol
vitamin E
Tonus
Sustained, partial contraction of a muscle. [More]
Torr
A unit of pressure equal to that exerted by a column of mercury 1 mm high; hence equal to the unit mm Hg.
Total fertility rate (TFR)
The average number of children in a family.
Toxin
Metabolic product (usually a protein) of an organism that is poisonous to another organism.
Toxoid
Toxin treated to destroy its poisonous quality but leaves it capable of stimulating the production of antibodies that will be able to bind to the unaltered toxin. The DTP vaccine contains both diphtheria and tetanus toxoid.
Tracheophyte
A plant with a vascular system of xylem and phloem. Includes all plants except mosses and their relatives.
Tranquilizers
Trans fatty acids
Transcription
The synthesis of a sequence of ribonucleotides complementary to the sequence of deoxyribonucleotides in a molecule of DNA. [Discussion]
Transcription factor
A protein needed to initiate the transcription of a gene. Some transcription factors bind to specific sequences of DNA (promoters and enhancers); others bind to each other; many bind both to DNA as well as to other transcription factors.
[selector genes] [glucocorticoid receptor][jun,fos,myc][E2F]
Transducin
Transformation
The modification of the genotype of a cell by introduction of DNA from another source. Also, the conversion of a normal cell into a cancerous one.[Discussion]
Transgenic
An animal or plant that has been deliberately transformed with a foreign gene and is able to pass that gene on to future generations in its gametes.[making transgenic mice] [making transgenic plants]
Transitions
[mutation]
Translation
The synthesis of a polypeptide in accordance with the genetic information encoded in a molecule of messenger RNA (mRNA).[Discussion]
Translocation
(1) Transfer of a piece of one chromosome to another, nonhomologous, chromosome. [More]. [Example: Philadelphia chromosome]
(2) Transport of proteins in (and out) of the endoplasmic reticulum.
(3) Transport of materials from one part of a plant to another.
Transmembrane protein
Protein that passes one or more times through the lipid bilayer of a cell membrane. [color schematic (48K)]
Transplantation
discussion of organ and tissue transplantation
Transpiration
Evaporation of water from plants.[More]
Transport vesicle
Membrane-enclosed structure that shuttles soluble as well as integral membrane proteins to various destinations within the cell. [More]
Tranversions
[mutation]
Tricyclic antidepressants
Triglyceride
Glycerol carrying three molecules of fatty acid. A fat. [More]
Trihalomethanes (THMs)
[by-products of water chlorination]
Trilinolein
[structure]
Trinucleotide repeats
[DNA]
Trisomy
[21]
Tristearin
[structure]
Trophic level
Position in a food chain such as a primary consumer or a secondary consumer.
Trophoblast
Tropism
Automatic response of growth or orientation in a direction determined by the direction from which the stimulus strikes the organism.
Trypsin
Tryptophan
[structure][repressor]
TSH
Thyroid-stimulating hormone
Tubular secretion
Tubulin
[and microtubules]
Tumor necrosis factor (TNF)
Cytokine that triggers apoptosis. [More] [secretion by Th1 cells]
Tumor Suppressor Genes
Discussion
Tundra
Relatively flat, treeless plain north of the taiga and south of the polar regions.
Turgor
Distention of the wall of a plant cell by the accumulation of water within the cell. [in guard cells of leaf]
Turner's syndrome
Described
Tyrosine
[structure]
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