Pregunta | Respuesta |
tRNA synthase | a protein enzyme that binds a specific class of transfer RNA molecules and binds a specific kind of amino acid to the. |
ultrastructure | biological structures within a cell that are larger than polymeric molecules but too small to be seen with microscopes. |
Microfossil | within sedimentary rock, fossils forms of prokaryotic cells that are detectable by microscopy. |
Direct panspermia | concept that generative life-forms have been seeded on this ( or another) planet by the purposeful actions of intelligent beings. |
RNA world | prebiotic/probiotic cellular environment in which RNA molecules served both informational and catalytic roles. |
L and D forms | two nonidentical, mirror image forms of molecule built around an asymmetic central carbon atom. |
reduced | an atom whose oxidation number has been decreased (by addition of an electron. |
methane | an organic compound whose molecules are composed of one carbon atom covalently bonded to four hydrogen atoms; also a fuel for cooking. |
geothermal vent | a break in the deep ocean floor which superheated water emerges; the water often contains reduced inorganic compounds. |
abiotic | anything not living; usually referring to physical aspects of an ecosystem. |
Chronic | a condition of disease the recurs through time usually of less severity than a sudden, acute condition or disease. |
tip structure | a morpholic region on the anterior region of some myccloplasmas; used to adhere to host cells and for motility. |
adhesin | a biomolecule; usually a protein on the surface region of a cell or structure that enables it to fix itself firmly to the surface of some other structure or host cell. |
degenerate | in reference to a cell, a biological structure or individual organism whose supposed evolutionary ancestors were larger, more complex or more well adapted. |
parasite | a microscopic organism living on or in another organism from which its gains nutrients and/or energy a the expense of the other organism. |
Host cell | a cell that supports the growth or reproduction of a virus, bacterium, or larger microbial form that has either entered or is in close association with it. |
Mycloplasma | a very small bacterium that lacks a cell wall; appears genetically related to genera Lactobacilllus and Clostidum much larger gram- positive bacteria having cell walls. |
extraceullular | a structure or process that is found or takes place outside of a living cell. |
broth culture | usually an aqueos solution containing sufficent nutrients to allow for the growth or maintenance of a particular kind of microorganism or a collection of related microorganisms. |
Overlap | in genetics a single sequence of DNA or RNA that contains information for two or more coding sequences or genes. |
Reading frames | a way of commencing the transcribing of a DNA sequence; since a new sequence of mRNA is read in condons of three bases each, there are three possible starting points and three reading frames for the same sequence of bases |
Primary flight feather | those large feathers on the distal portions of the avian wing which supports flight |
Cover feather | feathers that cover over other feathers smoothing the contour of the body surface for more efficient air flow. |
vertebrae | any animal that posses a dorsal, medial sequence of interarticulating bone segements; commonly referred to as a backbone. |
airfoil | a three deminsional shape designed to cause a desired response in a moving current of air, for example, an airplane wing |
keratin | light fibrous, sulfur containing proteins that contributing most of the structure of hair nails and feathers |
proximal | in anatomy located close to the central, internal surfaces of a body. |
calamus | the rounded, proximal (lower) portion of the shaft of a feather usually containing no barbs. |
sheath | in living systems a thin layer of cells or tissues or that which covers or protects an underlying structure. |
distal | far from; in anatomy characterizing structures that are far removed from the central, medial portion of a body or form. |
rachis | in compound leaves or feathers, a central shaft that supports leaflets or barbs extending laterally from it surfaces |
barb | a branch that extends laterally from the rachis or shaft of a feather a shaft in its own right supports smaller extensions called barbules. |
barbule | small keratinous extensions from the lateral surfaces of barbs; structures that impede the flow of air through a flight feather. |
Hooklet (barbicel) | a small curled projection from a barbule surface that latches into the groove ridge on the surface of an adjacent barbule; hold the barbs of a feather into a closed planar structure. |
Preen | in birds, the activity of drawing the bill along the space between feather barbs reestablishing hooklet and ridge attachments and thus the integrity of the feather surface. |
uropygial gland | structure in the base of the avian tail that secretes an oil used for preening and/or waterproofing the feathers. |
disulfide bond | a covalent bond formed between two sulfur atoms that helps stabilize the secondary structure of protein molecule. |
plaque | a localized thickened area or patch on surface such as the skin |
epidermis | the outermost external layer of cells within the skin many of the cells in this layer are already dead and soon to be sloughed off. |
dermal | of referring to the deeper, vascularized layer of the skin containing cells that divide to maintain the integrity of the skin as a surface barrier. |
follicle | the skin derived structure that gives rise to the feathers. |
socket wall | the outer epidermal surface of an avian follicle that contains and guides the growth of an internal prefeather structure collar-- an inner epidermal surface within an avian follicle that divides off keratinocytes that form the body of a feather. |
pulp | that internal dermal layer of cells within the follicle that is nutritive of the keratinocytes forming the feather. |
planar | referring to a flat, nearly two deminsonial surface. |
topological | referring to the surface contour of a three deminsonal shape |
down feather | a class of avian feathers that aid homethermic fowl to retain body heat. |
theistic evolution | the concept that the history of life is a long sequence of selection events operating on a corresponding sequence of divinely chosen mutations in the genetic information. |
irreducible complexity | a level of orderliness in a system whereby the removal of one component renders the rest of the system inoperable. |
neo- darwinian sythesis | the version of darwins theory in which Mendelian genes are the informational basis for the variations observed between members of a population |
antibiotic | a chemical from natural source or from a laboratory that limits the growth or kills microbes, mainly bacteria. |
mutagenic | any process or substance that causes changes in informational molecules such as DNA or RNA |
natural selection | that characteristic of the environment that favors the viability and reproductive activity of one individual in a population over another. |
selection pressure | any force within the environment that reduces the reproductive potential of one variety of individuals in a species over another variety |
speciation | the formation of two new species from one by an isolating process that allows two populations of a species to become genetically distinct from each other to the point of intersterility. |
algorithim | a defined sequence of steps. Often repetitive; used to solve math problems. |
cybernetics | the theoretical study of how highly automatic and inter-articulated systems are controlled. |
keel | in avian anatomy, the central (medial) pronounced ridge on the sternal bone of the bird where powerful flight muscles attach |
sternum | the breastbone; a compound, ventral bone to which ribs and skeletal musculature are attached. |
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