10Th Chem E

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earthquake a movement or trembling of the ground that is caused by a sudden release of energy when rocks along a fault move

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earthquake

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Earth science the scientific study of Earth and the universe around it

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Earth science

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earthshine sunlight illuminating the moon after having been reflected off the Earth

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earthshine

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eccentricity the degree of elongation of an elliptical orbit (symbol, e)

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eccentricity

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echinoderm a radially symmetrical marine invertebrate that has an endoskeleton, such as a starfish, a sea urchin, or a sea cucumber

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echinoderm

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echo a reflected sound wave

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echo

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echolocation the process of using reflected sound waves to find objects; used by animals such as bats

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echolocation

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eclipse an event in which the shadow of one celestial body falls on another

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eclipse

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ecliptic the apparent path that the sun takes through the stars during the year

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ecliptic

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ecological footprint a calculation that shows the productive area of Earth needed to support one person in a particular country

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ecological footprint

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ecological succession a gradual process of change and replacement in a community

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ecological succession

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ecology the study of the interactions of living organisms with one another and with their environment

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ecology

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economics the study of how individuals and groups make decisions about the production, distribution, and consumption of limited resources as the individuals or groups attempt to fulfill their needs and wants

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economics

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ecosystem a community of organisms and their a biotic environment

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ecosystem

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ecosystem services the role that organisms play in creating a healthful environment for humans

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ecosystem services

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ecotourism a form of tourism that supports the conservation and sustainable development of ecologically unique areas

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ectoderm

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ectoderm the outermost of the three germ layers of an embryo that develops into the epidermis and epidermal tissues, the nervous system, external sense organs, and the mucous membranes lining the mouth and anus

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ectoderm

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ectoparasite a parasite that lives on a host but does not enter the host's body

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ectoparasite

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ectoplasm in ciliates, the region in the cytoplasm that is located directly inside the cell membrane and that does not usually have organelles

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ectoplasm

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ectotherm an organism that needs sources of heat outside of itself

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ectotherm

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ectodermic describes the ability of an organism to maintain its body temperature by gaining heat from the environment

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ectodermic

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effective dose the amount of a drug needed to achieve the desired clinical improvement

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effective dose

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efferent neuron a neuron that conducts impulses away from the central nervous system

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efferent neuron

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effervescence a bubbling of a liquid caused by the rapid escape of a gas rather than by boiling

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effervescence

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efficiency a quantity, usually expressed as a percentage, that measures the ratio of work output to work input

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efficiency

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effusion the passage of a gas under pressure through a tiny opening

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effusion

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egg a sex cell produced by a female

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egg

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ejaculation the expulsion of seminal fluids from the urethra of the penis during sexual intercourse

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ejaculation

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elapid a venomous snake that has two small, fixed fangs in the front of the mouth

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elapid

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elastic collision a collision between ideally elastic bodies in which the final and initial kinetic energies are the same

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elastic collision

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the energy available for use when an elastic body returns to its original configuration

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elastic potential energy

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elastic rebound the sudden return of elastically deformed rock to its undeformed shape

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elastic rebound

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elastic rebound theory the theory that states that earthquakes are caused by the energy released when rocks that are deformed by stress suddenly break along a fault and return to their original shape

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elastic rebound theory

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electrical conduction a method of charging an object that occurs when electrons are free to move from one atom to another

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electrical conduction

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electrical conductor a material in which charges can move freely

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electrical conductor

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electrical energy the energy that is associated with charged particles because of their positions

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electrical energy

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electrical insulator a material in which charges cannot move freely

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electrical insulator

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electrical potential energy the ability to move an electric charge from one point to another

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electrical potential energy

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electric charge an electrical property of matter that creates electric and magnetic forces and interactions

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electric charge

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electric circuit a set of electrical components connected such that they provide one or more complete paths for the movement of charges

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electric circuit

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electric current the rate at which charges pass through a given point; measured in amperes

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electric current

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electric discharge the release of electricity stored in a source

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electric discharge

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electric field the space around a charged object in which another charged object experiences an electric force

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electric field

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electric force the force of attraction or repulsion on a charged particle that is due to an electric field

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electric force

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electric generator a device that converts mechanical energy into electrical energy

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electric generator

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electric motor a device that converts electrical energy into mechanical energy

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electric motor

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electric potential the electrical potential energy of a charged particle relative to that of the surface of the Earth, which has zero potential

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electric potential

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electric power the rate at which electrical energy is converted into other forms of energy

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electric power

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electrochemical cell a system that contains two electrodes separated by an electrolyte phase

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electrochemical cell

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electrochemistry the branch of chemistry that is the study of the relationship between electric forces and chemical reactions

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electrochemistry

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electrode a conductor used to establish electrical contact with a nonmetallic part of a circuit, such as an electrolyte

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electrode

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electrode potential the difference in potential between an electrode and its solution

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electrode potential

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electrolysis the process in which an electric current is used to produce a chemical reaction, such as the decomposition of water

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electrolysis

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electrolyte a substance that dissolves in water to give a solution that conducts an electric current

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electrolyte

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electrolytic cell an electrochemical device in which electrolysis takes place when an electric current is in the device

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electrolytic cell

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electromagnet a coil that has a soft iron core and that acts as a magnet when an electric current is in the coil

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electromagnet

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electromagneticinduction -the process of creating a current in a circuit by changing a magnetic field

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electromagneticinduction

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the radiation associated with an electric and magnetic field; it varies periodically and travels at the speed of light

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electromagnetic radiation

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all of the frequencies or wavelengths of electromagnetic radiation

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electromagneticspectrum

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electromagnetic wave a wave that consists of oscillating electric and magnetic fields, which radiate outward at the speed of light

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electromagnetic wave

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electromagnetism the interaction between electricity and magnetism

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electromagnetism

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electron a subatomic particle that has a negative charge

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electron

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electron affinity the energy needed to remove an electron from a negative ion to form a neutral atom or molecule

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electron affinity

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electron capture the process in which an inner orbital electron is captured by the nucleus of the atom that contains the electron

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electron capture

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electron cloud a region around the nucleus of an atom where electrons are likely to be found

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electron cloud

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electron configuration the arrangement of electrons in an atom

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electron configuration

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electronegativity a measure of the ability of an atom in a chemical compound to attract electrons

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electronegativity

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electron microscope a microscope that focuses a beam of electrons to magnify objects

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electron microscope

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electron transportchain a a series of molecules, found in the inner membranes of mitochondria and chloroplasts, through which electrons pass in a process that causes protons to build up on one side of the membrane

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electron transport chain

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electrophoresis the process by which electrically charged particles suspended in a liquid move through the liquid because of the influence of an electric field

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electrophoresis

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electroplating the electrolytic process of plating or coating an object with a metal

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electroplating

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element a substance that cannot be separated or broken down into simpler substances by chemical means; all atoms of an element have the same atomic number

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element

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elevation the height of an object above sea level

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elevation

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elimination reaction a reaction in which a simple molecule, such as water or ammonia, is removed and a new compound is produced

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elimination reaction

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ellipse a closed curve in which the sum of the distances from any point on the curve to two fixed points inside the curve, called foci, equals the sum of the distances from any other point on the curve to the same two fixed points

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ellipse

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elliptical galaxy a type of galaxy that has an elliptical appearance

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elliptical galaxy

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El Niño the warm-water phase of the El Niño–Southern Oscillation; a periodic occurrence in the eastern Pacific Ocean in which the surface-water temperature becomes unusually warm

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El Niño

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embryoan organism in an early stage of development of plants and animals

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embryo

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embryo in humans, a developing individual is referred to as an embryo from the second through the eighth week of pregnancy

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embryo

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embryo sac in plants, the female gametophyte that develops from a megaspore; contains the ovum that fuses with a sperm nucleus during fertilization to form an embryo and seven other cells, including the polar bodies that fuse with another sperm nucleus to form endosperm

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embryo sac

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emergent coastline the coast along which the sea level falls or the land rises

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emergent coastline

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emergent layer the top foliage layer in a forest where the trees extend above surrounding trees

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emergent layer

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emf electromotive force, the energy supplied by an electric current in a given source

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emf

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emigration the movement of an individual or group out of its native area

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emigration

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emission spectrum a diagram or graph that shows how much radiant energy a substance emits with respect to wavelength

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emission spectrum

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emphysema a degenerative disease, especially of the lungs, in which air accumulates in the tissues and destroys the alveoli

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emphysema

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empirical formula a chemical formula that shows the composition of a compound in terms of the relative numbers and kinds of atoms in the simplest ratio

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empirical formula

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emulsion any mixture of two or more immiscible liquids in which one liquid is dispersed in the other

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emulsion

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endangered species a species that has been identified to be in danger of extinction throughout all or a significant part of its range and that is thus under protection by regulations or conservation measures

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endangered species

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Endangered Species Act a act that the U.S. Congress passed in 1973 to protect any plant or animal species in danger of extinction

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Endangered Species Act

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endemic species a species that is native to a particular place and that is found only there

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endemic species

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endergonic reaction a chemical reaction that absorbs energy

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endergonic reaction

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endocrine gland a ductless gland that secretes hormones into the blood

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endocrine gland

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endocrine system a collection of glands and groups of cells that secrete hormones that regulate growth, development, and homeostasis; includes the pituitary, thyroid, parathyroid, and adrenal glands, the hypothalamus, the pineal body, and the gonads

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endocrine system

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endocytosis the process by which a cell membrane surrounds a particle and encloses the particle in a vesicle to bring the particle into the cell

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endocytosis

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endoderm the innermost germ layer of the animal embryo; develops into the epithelium of the pharynx, respiratory tract, digestive tract, bladder, and urethra

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endoderm

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Endodermis the single layer of cells that surrounds the vascular tissue in the roots and in some stems of plants; the innermost layer of cortex in seed plants

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endodermis

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endoparasite a parasite that lives inside a host's body

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endoparasite

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endoplasmic reticulum a system of membranes that is found in a cell's cytoplasm and that assists in the production, processing, and transport of proteins and in the production of lipids

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endoplasmic reticulum

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endoskeleton an internal skeleton made of bone and cartilage

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endoskeleton

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endosperm a triploid (3n) tissue that develops in the seeds of angiosperms and that provides food for a developing embryo

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endosperm

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endospore a thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions

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endospore

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endosymbiosis a mutually beneficial relationship in which one organism lives within another

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endosymbiosis

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endotherm an animal that can generate body heat through metabolism and can maintain a constant body temperature despite temperature changes in the animal's environment

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endotherm

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endothermic describes a process in which heat is absorbed from the environment

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endothermic

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endothermic reaction a chemical reaction that requires heat

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endothermic reaction

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endotoxin a bacterial toxin that forms within the bacterial cell and that is released when the bacterial cell breaks apart

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endotoxin

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end point the point in a titration at which a marked color change takes place

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end point

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energy the capacity to do work

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energy

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energy conservation the process of saving energy by reducing energy use and waste

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energy conservation

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energy conversion a change from one form of energy to another

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energy conversion

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energy efficiency the percentage of energy put into a system that does useful work

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energy efficiency

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energy level the energy state of an atom

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energy level

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energy pyramid a triangular diagram that shows an ecosystem's loss of energy, which results as energy passes through the ecosystem's food chain; each row in the pyramid represents a trophic (feeding) level in an ecosystem, and the area of a row represents the energy stored in that trophic level

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energy pyramid

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enkephalin a compound that is present in the brain and spinal cord that blocks pain

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enkephalin

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enthalpy the sum of the internal energy of a system plus the product of the system's volume multiplied by the pressure that the system exerts on its surroundings

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enthalpy

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entomology the study of insects

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entomology

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entropy a measure of the randomness or disorder of a system

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entropy

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Environment a membrane like layer that covers the capsids of some viruses

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environment

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environment in ecology, the surrounding natural conditions that affect the life and development of organisms

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environment in ecology

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environment in physics, the combination of conditions and influences that determine the behavior of a system

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environment in physics,

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environmental impact a statement an assessment of the effect of a proposed project or law on the environment

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environmental impact statement

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the combined effect of the factors in an environment that prevent an organism from achieving its full biological potential

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environmental resistance

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the study of the air, water, and land surrounding an organism or a community, which ranges from a small area to Earth's entire biosphere; it includes the study of the impact of humans on the environment

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environmental science

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enzyme a type of protein that speeds up metabolic reactions in plant and animals without being permanently changed or destroyed

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enzyme

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eon a unit of time equal to 1 billion years

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eon

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epicenter the point on Earth’s surface directly above an earthquake’s starting point, or focus

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epicenter

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epicotyls the portion of the stem of a plant embryo that is between the cotyledons and the first true leaves

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epicotyls

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epidemiology the study of the distribution of diseases in populations and the study of factors that influence the occurrence and spread of disease

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epidemiology

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epidermis the outer surface layer of cells of a plant or animal

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epidermis

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epididymis the long, coiled tube that is on the surface of a testis and in which sperm mature

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epididymis

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epiglottis a structure that hangs at the entrance of the larynx and prevents food from entering the larynx and the trachea while swallowing

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epiglottis

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epinephrine a hormone that is released by the adrenal medulla and that rapidly stimulates the metabolism in emergencies, decreases insulin secretion, and stimulates pulse and blood pressure; also called adrenaline

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epinephrine

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epiphyte a plant that uses another plant for support, but not for nourishment

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epiphyte

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epithelial tissue a tissue composed of cells that form a barrier between an organism and its external environment

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epithelial tissue

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epoch a subdivision of geologic time that is longer than an age but shorter than a period

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epoch

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equator the imaginary circle halfway between the poles that divides the Earth into the Northern and Southern Hemispheres

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equator

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equilibrium in biology, a state that exists when the concentration of a substance is the same throughout a space

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equilibrium

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equilibrium in physics, the state in which opposing forces balance each other

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equilibrium in physics,

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equilibrium in chemistry, the state in which a chemical process and the reverse chemical process occur at the same rate such that the concentrations of reactants and products do not change

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equilibrium in chemistry,

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equilibrium constant a number that relates the concentrations of starting materials and products of a reversible chemical reaction to one another at a given temperature

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equilibrium constant

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equilibrium vapor pressure the vapor pressure of a system at equilibrium

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equilibrium vapor pressure

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equinox the moment when the sun appears to cross the celestial equator

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equinox

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equivalence point the point at which the two solutions used in a titration are present in chemically equivalent amounts

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equivalence point

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era a unit of geologic time that includes two or more periods

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era

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erosion a process in which the materials of Earth's surface are loosened, dissolved, or worn away and transported from one place to another by a natural agent, such as wind, water, ice, or gravity

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erosion

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erratic a large rock transported from a distant source by a glacier

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erratic

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erythrocyte a red blood cell

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erythrocyte

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escape velocity the speed at which and direction in which a rocket must travel to completely break away from a planet's or moon's gravitational pull

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escape velocity

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esker a long, winding ridge of gravel and coarse sand deposited by glacial melt water streams

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esker

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esophagus a long, straight tube that connects the pharynx to the stomach

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esophagus

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ester an organic compound formed by combining an organic acid with an alcohol such that water is eliminated

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ester

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esterificationan organic reaction in which an acid reacts with an alcohol to form an ester and water

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esterification

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estivation a period of inactivity and lowered body temperature that some animals undergo in summer as a protection against hot weather and lack of food

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estivation

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estrogen a hormone that regulates the sexual development and reproductive function of females

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estrogen

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estuary an area where fresh water from rivers mixes with salt water from the ocean; the part of a river where the tides meet the river current

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estuary

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ethephon a chemical used as a growth regulator for fruit

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ethephon

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ether an organic compound in which two carbon atoms bond to the same oxygen atom

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ether

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Eubacteria in a traditional taxonomic system, a kingdom made up of all prokaryotes except members of the kingdom Archaebacteria; currently, biologists prefer to classify members of this kingdom into the domain Bacteria

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Eubacteria

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Eukaryain a modern taxonomic system, a domain made up of all eukaryotes; this domain aligns with the traditional kingdoms Protista, Fungi, Planate, and Animal

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Eukarya

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eukaryote an organism made up of cells that have a nucleus enclosed by a membrane, multiple chromosomes, and a mitotic cycle; eukaryotes include protists, animals, plants, and fungi but not archaea or bacteria

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eukaryote

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eukaryotic cell a cell that has a nucleus enclosed by a membrane, multiple chromosomes, and a mitotic cycle

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eukaryotic cell

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Eustachian tube a channel that connects the middle ear to the mouth cavity

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Eustachian tube

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eutrophic describes a lake or other body of water that contains a rich supply of plant nutrients

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eutrophic

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eutrophication an increase in the amount of nutrients, such as nitrates, in a marine or aquatic ecosystem

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eutrophication

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evaporation the change of state from a liquid to a gas

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evaporation

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evaporites sedimentary rocks formed from minerals left after water evaporates

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evaporites sedimentary

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evapotranspiration the total loss of water from an area, which equals the sum of the water lost by evaporation from the soil and other surfaces and the water lost by transpiration from organisms

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evapotranspiration

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evergreen describes woody plants that keep their leaves year-round

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evergreen

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evolution a heritable change in the characteristics within a population from one generation to the next; the development of new types of organisms from preexisting types of organisms over time

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evolution

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excess reactant the substance that is not used up completely in a reaction

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excess reactant

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excited state a state in which an atom has more energy than it does at its ground state

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excited state

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excretion the process of eliminating metabolic wastes

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excretion

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excurrent siphon a tube through which water exits the mantle cavity of a bivalve

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excurrent siphon

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exergonic reaction a reaction in which the end product has less energy than the original material did; normally associated with catabolism

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exergonic reaction

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exfoliation the separation of thin layers from surfaces of massive rock due to rain

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exfoliation

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exocrine gland a gland that discharges its secretions through a duct

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exocrine gland

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exocytosis the process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to let the substance out

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exocytosis

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exon the portion of the DNA sequence in a gene that contains the sequence of amino acids in a chain and the beginning and the end of a coding sequence

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exon

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exoskeleton a hard, external, supporting structure that develops from the ectoderm

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exoskeleton

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exosphere the outermost region of a planet's atmosphere in which the density is low enough that the lighter atmospheric atoms can escape into space

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exosphere

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exothermic describes a process in which a system releases heat into the environment

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exothermic

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exothermic reaction a chemical reaction in which heat is released to the surroundings

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exothermic reaction

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exotic species a species that is not native to a particular region

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exotic species

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exotoxin a potent, extra cellular toxin secreted by some bacteria

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exotoxin

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experiment a procedure that is carried out under controlled conditions to discover, demonstrate, or test a fact, theory, or general truth

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experiment

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experimental group in an experiment, a group that is identical to a control group except for one factor and that is compared with the control group

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experimental group

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experimentation the process of conducting an experiment

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experimentation

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exponential group with a logarithmic growth, or growth in which numbers increase by a certain factor in each successive time period

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experimental group

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extensive property a property that depends on the extent or size of a system

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extensive property

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extensor a muscle that extends a joint

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extensor

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external fertilization the union of gametes outside the bodies of the parents, as in many fishes and amphibians

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external fertilization

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external respiration the exchange of gases between the atmosphere and the lungs

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external respiration

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external stimulus a stimulus that comes from outside the body

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external stimulus

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extinct describes a species that has died out completely

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extinct

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extinction the death of every member of a species

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extinction

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extreme halophile a member of the group of archaebacteria that live in extremely salty environments

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extreme halophile

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rock that forms from the cooling and solidification of lava at Earth's surface

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extrusive igneous rock

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eyespot an organ that is covered by pigment in some invertebrates and protozoa and that detects changes in the quantity and quality of light

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eyespot