Abjad E

Glosarium ini diambil dari Buku Biologi Campbell | Jejak Mahasiswa

(EK-deh-sone) A steroid hormone that triggers molting in arthropods.
ecological efficiency 
The ratio of net productivity at one trophic level to net productivity at the next lower level.
ecological niche 
(nich) The sum total of an organism's utilization of the biotic and abiotic resources of its environment.
ecological succession 
Transition in the species composition of a biological community, often following ecological disturbance of the community; the establishment of a biological community in an area virtually barren of life.
The study of how organisms interact with their environments.
A level of ecological study that includes all the organisms in a given area as well as the abiotic factors with which they interact; a community and its physical environment.
(EK-tuh-durm) The outermost of the three primary germ layers in animal embryos; gives rise to the outer covering and, in some phyla, the nervous system, inner ear, and lens of the eye.
(EK-toh-thurm) An animal, such as a reptile, fish, or amphibian, that must use environmental energy and behavioral adaptations to regulate its body temperature.
effector cell 
A muscle cell or gland cell that performs the body's responses to stimuli; responds to signals from the brain or other processing center of the nervous system.
ejaculatory duct 
In the male, a duct from each testis that join to form the urethra.
electrochemical gradient 
The diffusion gradient of an ion, representing a type of potential energy that accounts for both the concentration difference of the ion across a membrane and its tendency to move relative to the membrane potential.
electrogenic pump 
An ion transport protein generating voltage across the membrane.
electromagnetic spectrum
The entire spectrum of radiation; ranges in wavelength from less than a nanometer to more than a kilometer.
electron carrier 
A molecule that conveys electrons; one of several membrane proteins in electron transport chains in cells. Electron carriers shuttle electrons during the redox reactions that release energy used to make ATP.
electron microscope 
(EM) A microscope that focuses an electron beam through a specimen, resulting in resolving power a thousandfold greater than that of a light microscope. A transmission electron microscope (TEM) is used to study the internal structure of thin sections of cells. A scanning electron microscope (SEM) is used to study the fine details of cell surfaces.
electron shell 
An energy level at which an electron orbits the nucleus of an atom.
electron transport chain 
A sequence of electron-carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.
A particle with a single negative charge; one or more electrons orbit the nucleus of the atom.
The tendency for an atom to pull electrons toward itself.
Any substance that cannot be broken down to any other substance.
embryo sac 
The female gametophyte of angiosperms, formed from the growth and division of the megaspore into a multicellular structure with eight haploid nuclei.
(EM-bree-oh) A developing stage of multicellular organisms; in humans, the stage in the development of offspring from the first division of the zygote until body structures begin to appear; about the ninth week of gestation.
(eh-NAN-she-uh-mer) One of a pair of molecules that are mirror-image isomers of each other.
endergonic reaction 
(EN-dur-GON-ik) A nonspontaneous chemical reaction in which free energy is absorbed from the surroundings.
endocrine gland 
(EN-doh-krin) A ductless gland that secretes hormones directly into the bloodstream.
endocrine system 
The internal system of chemical communication involving hormones, the ductless glands that secrete hormones, and the molecular receptors on or in target cells that respond to hormones; functions in concert with the nervous system to effect internal regulation and maintain homeostasis.
(EN-doh-sy-TOH-sis) The cellular uptake of macromolecules and particulate substances by localized regions of the plasma membrane that surround the substance and pinch off to form an intracellular vesicle.
(EN-doh-durm) The innermost of the three primary germ layers in animal embryos; lines the archenteron and gives rise to the liver, pancreas, lungs, and the lining of the digestive tract.
(EN-doh-DUR-mis) The innermost layer of the cortex in plant roots; a cylinder one cell thick that forms the boundary between the cortex and the stele.
endomembrane system 
The collection of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.
(EN-doh-MEE-tree-um) The inner lining of the uterus, which is richly supplied with blood vessels.
endoplasmic reticulum 
(ER) (EN-doh-plaz-mik reh-TIK-yoo-lum) An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.
(en-DOR-fin) A hormone produced in the brain and anterior pituitary that inhibits pain perception.
(EN-doh-SKEL-eh-ton) A hard skeleton buried within the soft tissues of an animal, such as the spicules of sponges, the plates of echinoderms, and the bony skeletons of vertebrates.
(EN-doh-spurm) A nutrient-rich tissue formed by the union of a sperm cell with two polar nuclei during double fertilization, which provides nourishment to the developing embryo in angiosperm seeds.
A thick-coated, resistant cell produced within a bacterial cell exposed to harsh conditions.
endosymbiotic theory 
(EN-doh-SIM-by-OT-ik) A hypothesis about the origin of the eukaryotic cell, maintaining that the forerunners of eukaryotic cells were symbiotic associations of prokaryotic cells living inside larger prokaryotes.
(EN-doh-THEEL-ee-um) The innermost, simple squamous layer of cells lining the blood vessels; the only constituent structure of capillaries.
(EN-doh-thurm) An animal that uses metabolic energy to maintain a constant body temperature, such as a bird or mammal.
(EN-doh-TOKS-in) A component of the outer membranes of certain gram-negative bacteria responsible for generalized symptoms of fever and ache.
energy of activation (EA) 
The amount of energy that reactants must absorb before a chemical reaction will start.
The capacity to do work by moving matter against an opposing force.
A DNA sequence that recognizes certain transcription factors that can stimulate transcription of nearby genes.
(EN-truh-pee) A quantitative measure of disorder or randomness, symbolized by S.
environmental grain 
An ecological term for the effect of spatial variation, or patchiness, relative to the size and behavior of an organism.
A class of proteins serving as catalysts, chemical agents that change the rate of a reaction without being consumed by the reaction.
(EP-eh-DER-mis) (1) The dermal tissue system in plants. (2) The outer covering of animals.
(EP-ih-DID-eh-mis) A long coiled tube into which sperm pass from the testis and are stored until mature and ejaculated.
(EP-eh-JEN-eh-sis) The progressive development of form in an embryo.
A cartilaginous flap that blocks the top of the windpipe, the glottis, during swallowing, which prevents the entry of food or fluid into the respiratory system.
A hormone produced as a response to stress; also called adrenaline.
(EP-eh-fite) A plant that nourishes itself but grows on the surface of another plant for support, usually on the branches or trunks of tropical trees.
(EP-eh-some) A plasmid capable of integrating into the bacterial chromosome.
A phenomenon in which one gene alters the expression of another gene that is independently inherited.
epithelial tissue 
(EP-eh-THEEL-ee-ul) Sheets of tightly packed cells that line organs and body cavities.
A localized region on the surface of an antigen that is chemically recognized by antibodies; also called antigenic determinant.
(er-RITH-roh-site) A red blood cell; contains hemoglobin, which functions in transporting oxygen in the circulatory system.
(eh-SOF-eh-gus) A channel that conducts food, by peristalsis, from the pharynx to the stomach.
essential amino acids 
The amino acids that an animal cannot synthesize itself and must obtain from food. Eight amino acids are essential in the human adult.
(ES-teh-VAY-shun) A physiological state characterized by slow metabolism and inactivity, which permits survival during long periods of elevated temperature and diminished water supplies.
(ES-troh-jens) The primary female steroid sex hormones, which are produced in the ovary by the developing follicle during the first half of the cycle and in smaller quantities by the corpus luteum during the second half. Estrogens stimulate the development and maintenance of the female reproductive system and secondary sex characteristics.
estrous cycle 
(ES-trus) A type of reproductive cycle in all female mammals except higher primates, in which the nonpregnant endometrium is reabsorbed rather than shed, and sexual response occurs only during midcycle at estrus.
(ETH-ul-een) The only gaseous plant hormone, responsible for fruit ripening, growth inhibition, leaf abscission, and aging.
(yoo-KROH-muh-tin) The more open, unraveled form of eukaryotic chromatin, which is available for transcription.
eukaryotic cell 
(YOO-kar-ee-OT-ik) A type of cell with a membrane-enclosed nucleus and membrane-enclosed organelles, present in protists, plants, fungi, and animals; also called eukaryote.
(YOO-met-uh-ZOH-uh) Members of the subkingdom that includes all animals except sponges.
eutrophic lake 
A highly productive lake, having a high rate of biological productivity supported by a high rate of nutrient cycling.
evaporative cooling 
The property of a liquid whereby the surface becomes cooler during evaporation, owing to a loss of highly kinetic molecules to the gaseous state.
All the changes that have transformed life on Earth from its earliest beginnings to the diversity that characterizes it today.
excitatory postsynaptic potential 
(EPSP) (POST-sin-AP-tik) An electrical change (depolarization) in the membrane of a postsynaptic neuron caused by the binding of an excitatory neurotransmitter from a presynaptic cell to a postsynaptic receptor; makes it more likely for a postsynaptic neuron to generate an action potential.
The disposal of nitrogen-containing waste products of metabolism.
excretory system 
The organ system that disposes of nitrogen-containing metabolic wastes.
exergonic reaction 
(EKS-ur-GON-ik) A spontaneous chemical reaction in which there is a net release of free energy.
(EKS-oh-sy-TOH-sis) The cellular secretion of macromolecules by the fusion of vesicles with the plasma membrane.
The coding region of a eukaryotic gene that is expressed. Exons are separated from each other by introns.
A hard encasement on the surface of an animal, such as the shells of mollusks or the cuticles of arthropods, that provides protection and points of attachment for muscles.
(EKS-oh-TOKS-in) A toxic protein secreted by a bacterial cell that produces specific symptoms even in the absence of the bacterium.
exponential population growth 
The geometric increase of a population as it grows in an ideal, unlimited environment.
extraembryonic membranes
(EKS-truh-EM-bree-AHN-ik) Four membranes (yolk sac, amnion, chorion, allantois) that support the developing embryo in reptiles, birds, and mammals.


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