Abjad T

JEJAK
MAHASISWA
..:: KAMUS BIOLOGI JEJAK MAHASISWA ::..
Dibuat
12/19/2011
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
Glosarium ini diambil dari Buku Biologi Campbell | Jejak Mahasiswa


T cell
A type of lymphocyte responsible for cell-mediated immunity that differentiates under the influence of the thymus.
taiga
(TY-guh) The coniferous or boreal forest biome, characterized by considerable snow, harsh winters, short summers, and evergreen trees.
taxis
(TAKS-iss) A movement toward or away from a stimulus.
taxon
(plural, taxa) The named taxonomic unit at any given level.
taxonomy
The branch of biology concerned with naming and classifying the diverse forms of life.
telomere
The protective structure at each end of a eukaryotic chromosome. Specifically, the tandemly repetitive DNA (see repetitive DNA) at the end of the chromosomeƕs DNA molecule.
telophase
The fourth and final stage of mitosis, during which daughter nuclei form at the two poles of a cell. Telophase usually occurs together with cytokinesis.
temperate deciduous forest
A biome located throughout midlatitude regions where there is sufficient moisture to support the growth of large, broad-leaf deciduous trees.
temperate virus
A virus that can reproduce without killing the host.
temperature
A measure of the intensity of heat in degrees, reflecting the average kinetic energy of the molecules.
tendon
A type of fibrous connective tissue that attaches muscle to bone.
terminator
A special sequence of nucleotides in DNA that marks the end of a gene; it signals RNA polymerase to release the newly made RNA molecule, which then departs from the gene.
tertiary structure
(TUR-shee-air-ee) Irregular contortions of a protein molecule due to interactions of side chains involved in hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.
testcross
Breeding of an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype. The ratio of phenotypes in the offspring determines the unknown genotype.
testis
(plural, testes) The male reproductive organ, or gonad, in which sperm and reproductive hormones are produced.
testosterone
The most abundant androgen hormone in the male body.
tetanus
(TET-un-us) The maximal, sustained contraction of a skeletal muscle, caused by a very fast frequency of action potentials elicited by continual stimulation.
tetrapod
A vertebrate possessing two pairs of limbs, such as amphibians, reptiles, birds, and mammals.
thalamus
(THAL-uh-mus) One of two integrating centers of the vertebrate forebrain. Neurons with cell bodies in the thalamus relay neural input to specific areas in the cerebral cortex and regulate what information goes to the cerebral cortex.
thermoregulation
The maintenance of internal temperature within a tolerable range.
thick filament
A filament composed of staggered arrays of myosin molecules; a component of myofibrils in muscle fibers.
thigmomorphogenesis
A response in plants to chronic mechanical stimulation, resulting from increased ethylene production; an example is thickening stems in response to strong winds.
thigmotropism
(THIG-moh-TROH-piz-um) The directional growth of a plant in relation to touch.
threshold potential
The potential an excitable cell membrane must reach for an action potential to be initiated.
thylakoid
(THY-luh-koid) A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy.
thymus
(THY-mus) An endocrine gland in the neck region of mammals that is active in establishing the immune system; secretes several messengers, including thymosin, that stimulate T cells.
thyroid gland
An endocrine gland that secretes iodine-containing hormones (T3 and T4), which stimulate metabolism and influence development and maturation in vertebrates, and cacitonin, which lowers blood calcium levels in mammals.
thyroid-stimulating hormon
(TSH) A hormone produced by the anterior pituitary that regulates the release of thyroid hormones.
Ti plasmid
A plasmid of a tumor-inducing bacterium that integrates a segment of its DNA into the host chromosome of a plant; frequently used as a carrier for genetic engineering in plants.
tight junction
A type of intercellular junction in animal cells that prevents the leakage of material between cells.
tissue
An integrated group of cells with a common structure and function.
tonoplast
A membrane that encloses the central vacuole in a plant cell, separating the cytosol from the cell sap.
totipotency
The ability of embryonic cells to retain the potential to form all parts of the animal.
trace element
An element indispensable for life but required in extremely minute amounts.
trachea
(TRAY-kee-uh) The windpipe; that portion of the respiratory tube that has C-shaped cartilagenous rings and passes from the larynx to two bronchi.
tracheae
(TRAY-kee-ee) Tiny air tubes that branch throughout the insect body for gas exchange.
tracheal system
A gas exchange system of branched, chitin-lined tubes that infiltrate the body and carry oxygen directly to cells in insects.
tracheid
(TRAY-kee-id) A water-conducting and supportive element of xylem composed of long, thin cells with tapered ends and walls hardened with lignin.
transcription factor
A regulatory protein that binds to DNA and stimulates transcription of specific genes.
transcription
The synthesis of RNA on a DNA template.
transfer RNA
(tRNA) An RNA molecule that functions as an interpreter between nucleic acid and protein language by picking up specific amino acids and recognizing the appropriate codons in the mRNA.
transformation
(1) The conversion of a normal animal cell to a cancerous cell. (2) A phenomenon in which external DNA is assimilated by a cell.
translation
(1) The conversion of a normal animal cell to a cancerous cell. (2) A phenomenon in which external DNA is assimilated by a cell.
translocation
(1) An aberration in chromosome structure resulting from an error in meiosis or from mutagens; attachment of a chromosomal fragment to a nonhomologous chromosome. (2) During protein synthesis, the third stage in the elongation cycle when the RNA carrying the growing polypeptide moves from the A site to the P site on the ribosome. (3) The transport via phloem of food in a plant.
transpiration
The evaporative loss of water from a plant.
transposon
(trans-POH-son) A transposable genetic element; a mobile segment of DNA that serves as an agent of genetic change.
triplet code
A set of three-nucleotide-long words that specify the amino acids for polypeptide chains.
triploblastic
Possessing three germ layers: the endoderm, mesoderm, and ectoderm. Most eumetazoa are triploblastic.
trophic level
The division of species in an ecosystem on the basis of their main nutritional source. The trophic level that ultimately supports all others consists of autotrophs, or primary producers.
trophic structure
The different feeding relationships in an ecosystem that determine the route of energy flow and the pattern of chemical cycling.
trophoblast
The outer epithelium of the blastocyst, which forms the fetal part of the placenta.
tropic hormone
A hormone that has another endocrine gland as a target.
tropical rain forest
The most complex of all communities, located near the equator where rainfall is abundant; harbors more species of plants and animals than all other terrestrial biomes combined.
tropism
A growth response that results in the curvature of whole plant organs toward or away from stimuli due to differential rates of cell elongation.
tumor
A mass that forms within otherwise normal tissue, caused by the uncontrolled growth of a transformed cell.
tumor-suppressor gene
A gene whose protein products inhibit cell division, thereby preventing uncontrolled cell growth (cancer).
tundra
A biome at the extreme limits of plant growth; at the northernmost limits, it is called arctic tundra, and at high altitudes, where plant forms are limited to low shrubby or matlike vegetation, it is called alpine tundra.
turgid
(TUR-jid) Firm; walled cells become turgid as a result of the entry of water from a hypotonic environment.
turgor pressure
The force directed against a cell wall after the influx of water and the swelling of a walled cell due to osmosis.

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