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tracer:
Molecule or atom that has been labeled either chemically or radioactively
so that it can be followed in a biochemical process or readily
located in a cell or tissue.
transcript:
RNA product of DNA transcription.
transcription (DNA transcription):
Copying of one strand of DNA into a complementary RNA sequence
by the enzyme RNA polymerase.
transcription factor:
Term loosely applied to any protein required to initiate or regulate
transcription in eucaryotes. Includes both gene regulatory proteins
as well as the general transcription factors.
transfection:
Introduction of a foreign DNA molecule into a eucaryotic cell;
usually followed by expression of one or more genes in the newly
introduced DNA.
transfer ribonucleic acid:
see tRNA
transformation:
Heritable alteration in the properties of a eucaryotic cell. In
the case of cultured animal cells, usually refers to the acquisition
of cancerlike properties following treatment with a virus or a
carcinogen.
transgenic:
Describes a plant or animal that has stably incorporated one or
more genes from another cell or organism and can pass them on
to successive generations.
transition state:
Structure that forms transiently in the course of a chemical reaction
and has the highest free energy of any reaction intermediate;
a rate-limiting step in the reaction.
translation (RNA translation):
Process by which the sequence of nucleotides in a messenger RNA
molecule directs the incorporation of amino acids into protein;
occurs on a ribosome.
transposable element:
Segment of DNA that can move from one position in a genome to
another.
triglyceride:
Glycerol ester of fatty acids. The main constituent of fat droplets
in animal tissues (where the fatty acids are saturated) and of
vegetable oil (where the fatty acids are mainly unsaturated).
tRNA (transfer ribonucleic acid):
Set of small RNA molecules used in protein synthesis as an interface
(adaptor) between mRNA and amino acids. Each type of tRNA molecule
is covalently linked to a particular amino acid.
tyrosine kinase:
Enzyme that transfers the terminal phosphate of ATP to a specific
tyrosine residue on its target protein.
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