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Flashcards in Science Terms Deck (117):
1

acid rain

the formation of acidic rain drops by reaction with chemicals produced by burning fossil fuels

2

alleles

different forms of a gene, some of which may be dominant and some, recessive

3

alternating current (AC)

electricity produced by a generator, in which electrons move back and forth

4

amino acids

molecular building blocks of proteins

5

animals

multicellular organisms that obtain their energy and raw materials from the biomolecules of other organisms

6

antimatter

particles that, when combined with their oppositely charged matter particles, annihilate to form energy

7

astronomy

the science of collecting, analyzing, and interpreting photons from space

8

atom

a submicroscopic particle from which solids, liquids, and gases are made atomic number: the number of protons in an atom, which defines the element battery: a device that applies a continuous motive force to electrons

9

big bang theory

the theory that proposes that the universe came into existence at one moment in time, and subsequently has undergone rapid expansion

10

biology

the study of living systems

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black hole

: the collapse of the remnants of a massive star into a point, from which even light cannot escape

12

cancer

a disease that occurs when defects in the genetic machinery cause a cell to divide again and again to form a tumor

13

carbohydrates

energy-rich molecules composed of carbon, hydrogen, and oxygen; the most abundant biomolecules on Earth

14

cell

the basic unit of all living things

15

Cenozoic Era

the period of Earth history from 65 million years ago to the present; the age of mammals

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chemical reactions

the breakdown or rearrangement of atoms into different substances

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chemistry

the study of atomic interactions

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chromosome

the structure in a cell that carries genes in the chemical DNA

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climate

a long-term average of weather for a given region

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computer

a machine that stores and processes information

21

conduction

the movement of heat by atomto-atom contact

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convection

the movement of heat by transfer of a mass of fluid

23

convergent boundary

a plate boundary where two plates move together core: the inner metallic layers of the Earth

24

covalent bond

a chemical bond in which two or more atoms share electrons crust: the outer layer of the solid Earth

25

deoxyribonucleic acid (DNA)

the chemical that carries genetic information

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direct current (DC)

electricity produced by a battery, in which electrons flow in one direction

27

divergent boundary

a plate boundary where two plates move apart and new crust is formed

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earth science

the study of our planet's history and present dynamic state

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earthquakes

sudden Earth movements that result from the gradual buildup of stress and subsequent fracture between two blocks of rock

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ecosystems

complex communities of organisms and their physical environment

31

electric circuit

a system that incorporates a source of electrical energy, a device that responds to this electrical potential and a closed loop of conducting material

32

electricity

the motion of electrons in a closed circuit

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electromagnetic radiation

a form of wave energy produced whenever an electric charge accelerates; travels at the speed of light

34

electromagnetic spectrum

the continuum of all possible wavelengths of electromagnetic radiation, including radio, microwaves, infrared radiation, light, ultraviolet, x-rays, and gamma rays

35

electron

subatomic particle that carries a negative electric charge and participates in chemical bonding

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element

a substance that cannot be broken down into other substances by any ordinary physical or chemical means

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energy

the ability to do work

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entropy

the ratio of heat energy over temperature; a measure of the disorder of a physical system

39

eukaryotes

single-celled organisms with a nucleus and other organelles

40

evolution

the process by which life has changed over billions of years of Earth history

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extinction

the disappearance of a species

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fission reactions

nuclear reactions that split an atom

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force

the phenomenon that causes an object to accelerate

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fossil

any evidence of ancient life; usually preserved in rock

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fossil fuel

a carbon-based fuel obtained from the Earth, including coal, petroleum, and natural gas

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fungi

organisms that resemble plants in terms of their cell structure and growth patterns, but are nonphotosynthetic

47

fusion reactions

nuclear reactions that combine two nuclei, usually hydrogen galaxies: collections of billions of gravitationally bound stars

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genetic disease

a disease that arises from a defective gene

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genetic engineering

the process of consciously altering a coded sequence of DNA or RNA to produce an organism with new characteristics

50

genetics

the study of the ways by which biological information is passed down from parents to offspring

51

gravity

an attractive force that exists between any two masses

52

greenhouse effect

the warming of the Earth's surface by atmospheric gases, notably carbon dioxide, that trap infrared radiation

53

Human Genome Project

a project that will provide a detailed map of the distribution of genes on the 23 human chromosomes, and the sequence of bases hydrocarbons: compounds of carbon and hydrogen

54

igneous rocks

all rocks that form from a molten state

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ionic bond

a chemical bond that forms through an exchange of one or more electrons

56

isotope

an atom for which the number of protons and neutrons are known

57

istocacy

an earlier geological concept that held that mountains were great rafts of relatively light material buoyed up like icebergs on the ocean

58

laser

a device that emits an intense narrow light beam of a single wavelength (an acronym for Light Amplification by Simulated Emission of Radiation)

59

leptons

a class of six particles, including electrons and neutrinos, that do not occur in the atom's nucleus

60

Linnaean system

the system of nomenclature that assigns a specific name to each kind of organism

61

lipids

biomolecules including fats, oils, and waxes; building blocks of cell membranes

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lithosphere

the strong rock layer that includes the crust and the top part of the mantle of the Earth; it is relatively thin, cold, and brittle and is typically between 50-100 km in thickness

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mantle

rocky layers of the Earth interior; mantle convection drives plate tectonics

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mass

an object's tendency to resist an acceleration

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mass extinction

a time in geological history when a large percentage of species become extinct

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Mesozoic Era

the period of Earth history from 248 to 65 million years ago; the age of dinosaurs

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messenger RNA

the molecule that copies the base sequence of a DNA segment (a gene) letter by letter

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metabolism

the cell's process of obtaining and using energy from its surroundings

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metallic bond

a chemical bond that forms when all atoms release electrons, creating a " sea " of negatively charged electrons with positively charged atoms interspersed

70

metamorphic rocks

all rocks whose mineralogy is altered by the effects of temperature and pressure

71

microchip, or integrated circuit

a semiconductor device that may incorporate thousands of transistor-like regions

72

natural selection

the theory that life evolves by the gradual, selective transmission of desirable traits from one generation to the next

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nebular hypothesis

a widely accepted model for the formation of stars, including the solar system

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neutrons

electrically neutral nuclear particles with mass slightly greater than that of a proton

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nuclear reactor

a device that produces electrical energy by sustained nuclear fission reaction

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nucleus (of atoms)

tiny object that carries most of an atom's mass

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nucleus (of cell)

the central organelle of eukaryote cells; contains the cell's DNA

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organelles

discrete internal structures in a eukaryotic cell; the nucleus is an example

79

organic chemistry

the field of chemistry devoted to carbon compounds

80

ozone hole

a region over the Antarctic with seasonally reduced ozone

81

ozone layer

a region of the stratosphere, containing small amounts of the gas ozone (03), which absorbs much of the Sun's harmful UVB ultraviolet radiation

82

paleoclimatology

the study of ancient climates

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Paleozoic Era

the period of Earth history from 543 to 248 million years ago, characterized by the appearance of animals with hard parts

84

plastic

a solid formed from complexly intertwined polymer strands

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phase transformation

a change in state or atomic structure, often resulting from changes in temperature or pressure

86

photon

an individual packet of electromagnetic radiation

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physics

the study of matter in motion

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plants

multicellular organisms that obtain their energy from the sunlight

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plate tectonics

the theory that the surface of the Earth is divided into about a dozen thin, brittle, mobile plates

90

polymer

a large molecular structure composed of chains of small molecules

91

polymerase chain reaction (PCR):

a technique to duplicate a specific strand of DNA

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Precambrian Era

the period of geological history before 543 million years ago

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prokaryote

single-celled organisms without any well defined internal structures, such as a nucleus

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proteins

chemical workhorses of life, built from chains of amino acids, their structure determines their function

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proton

positively-charged nuclear particle, present in all atoms

96

pulsar

a neutron star that emits brief sharp pulses of energy as opposed to the steady release of energy typically encountered.

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punctuated equilibrium

the theory of evolution that claims species change in relatively sudden bursts

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quantum mechanics

the study of motions at the scale of quantum jumps

99

quarks

: a class of six different particles that combine in twos or threes to form neutrons, protons, and other nuclear particles

100

radiation

the movement of heat by electromagnetic radiation; also the energetic particles produced by radioactive atoms

101

radioactivity

the spontaneous release of nuclear energy from an atom

102

relativity

the theory that the laws of nature are the same in every reference frame

103

ribonucleic acid (RNA)

the molecule that transforms DNA into proteins

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scientific method

a cyclic process of inquiry based on observations, synthesis, hypothesis, and predictions that lead to more observations

105

sedimentary rocks

all rocks that are deposited in layers

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seismology

the study of the Earth with sound waves

107

semiconductors

materials that conduct electricity, but not very well

108

SETI

the search for extraterrestrial intelligence; involves looking for characteristic radio signals from nearby Sun-like stars

109

solar system

all objects that are gravitationally bound to the Sun spectroscopy: the study of light-matter interactions

110

states of matter

solid, liquid, gas, and plasma, which are manifestations of submicroscopic organization of atoms

111

superconductors

materials that conduct electricity without any resistance supernova: the sudden collapse and subsequent explosion of a star taxonomy: the formalized procedure for classifying and naming life forms

112

transfer RNA

the molecule that matches three bases on messenger RNA to an amino acid

113

transform boundary

a plate boundary where two plates move past each other

114

virus

a strand of genetic material (DNA or RNA) surrounded by a coating of proteins; viruses can take over a cell's genetic machinery

115

volcano

a mountain or other feature that forms when molten rock erupts as lava and accumulates at the surface

116

waves

a way to move energy without moving mass

117

weather

the state of the atmosphere at a given time and place work: the exertion of a force over a distance