Self And The Phenomenon Of Life: A Biologist Examines Life From Molecules To Humanity

Glossary 361

“9x6” b2726 Self and the Phenomenon of Life: A Biologist Examines Life from Molecules to Humanity

Thalamus: A deep brain gray matter structure that serves as the major sensory

relay station from the body to the cerebral cortex. It plays an important role

in consciousness; also involved in motor regulation.

Toll-like receptor: A type of receptor found on animal cell surface capable of

recognizing pathogens; it functions as part of innate immunity.

Transcription: The transfer of information from DNA to messenger RNA.

Transfer RNA (tRNA): RNA molecule responsible for bringing amino acids

to the ribosome to be assembled into proteins according to the information

contained in the messenger RNA.

Translation: The transfer of information from messenger RNA to protein.

Tricarboxylic acid (TCA) cycle: A series of metabolic steps taking place in the

mitochondria by which the acetyl component from food is processed before

electron transfer and oxidative phosphorylation.

tRNA: see Transfer RNA.

Ventral pallidum: A deep brain structure in the temporal lobe involved in

reward and motivation.

Ventral tegmental area (VTA): A deep brain structure in the midbrain that

forms fiber projections collectively called “dopaminergic mesolimbic reward

system.” Involved in craving behavior, motivation and pleasure.

Ventro-medial prefrontal cortex (vmPFC): The lower (ventral) and midline

(medial) part of the prefrontal cortex. It plays a major role in the execu-

tive functions of the brain. Also coordinates the various emotional centers,

bringing emotion to the conscious level, and serving as liaison between ratio-

nality and animal impulse. Also known as orbito-frontal cortex.

Visceral: Refers to the internal organs.

VTA: see Ventral tegmental area.

Watson-Crick model of DNA: A model that visualizes DNA as a twisted lad-

der (double helix) with a chain of alternating molecules of deoxy-ribose and

phosphate on each side, and with the pairing of the nucleobases as the rungs,

the pairing being adenine (A) to thymine (T), and guanine (G) to cytosine (C).

White blood cells: Cellular components of blood other than the red blood cells.

White blood cells are responsible for immune and other defense functions.

White matter: The deeper part of the brain below the gray matter containing

myelinated nerve fibers (axons). So-called because of the whitish appearance

produced by the myelin.

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