| A | B |
|---|
| Word | Definition |
| Acceleration | the rate of change in speed |
| Active transport | process requiring energy by which cells move materials |
| Adaptation | evolution of structural, internal, or behavioral features that help an organism better survive in its environment |
| AIDS (acquired immune deficiency syndrome) | caused by HIV, which damages the immune system |
| Allele | gene form for each variation of a trait of an organism |
| Amplitude | the maximum distance an object moves from equilibrium in any periodic motion |
| Animals | multicellular consumers that eat other organisms for food |
| Antibiotic | microbial or fungal product that kills or inhibits the growth of other microorganisms |
| Archaebacteria | group of prokaryotes that produce glucose by chemosynthesis rather than by photosynthesis |
| ATP | adenosine triphosphate; energy-storing molecule that serves as the cell’s “energy currency” |
| Bacteria | microscopic, prokaryotic cells; the smallest and simplest of living things |
| Battery | a group of cells connected together to convert chemical energy to electric energy |
| Behavior | response of an animal to an environmental stimulus |
| Buoyancy | ability of a fluid to exert an upward force on an object immersed in the fluid (some textbooks call this buoyant force.) |
| Carbon cycle | the cycle in which carbon dioxide is fixed by photosynthetic organisms to form organic nutrients and is ultimately restored to the inorganic state by respiration and decay |
| Cell membrane | the boundary between the cell and its external environment; allows materials such as oxygen to enter and waste products to leave (Some textbooks call this the plasma membrane.) |
| Chemical change | a process involving one or more substance changing into new substances |
| Chemical property | the ability or inability of a substance to combine with or change into new substances |
| Chloroplasts | chlorophyll-containing organelle found in green plants and some protists |
| Circulatory System | includes the heart, blood vessels, and blood |
| Commensalism | symbiotic relationship in which one species benefits and the other species is neither harmed nor helped |
| Conduction | the process that transfers kinetic energy when particles collide |
| Control | the part of the experiment in which all condition are kept constant |
| Convection | the transfer of heat by means of motion in a fluid |
| Covalent bond | a chemical bond that results from the sharing of valence electrons |
| Density | a ratio that compares the mass of an object to its volume (g/cm3) |
| Digestion | the process of making food absorbable by breaking it down into simpler chemical compounds |
| Digestive System | receives and breaks down food and absorbs nutrients |
| DNA | deoxyribonucleic acid; the master copy of an organism’s information code |
| Dominant | visible, observable trait of an organism that masks a recessive form of the trait |
| Ecosystem | populations in a community and the abiotic factors with which they interact |
| Efficiency | the ratio of output work to input work |
| Electrolyte | an ionic compound whose aqueous solution conducts an electric current |
| Endocrine System | controls the metabolic activities of the body |
| Endoplasmic reticulum | membranes forming a type of transport system |
| Energy transformation | a change from one form of energy to another, such as electrical energy to thermal energy |
| Eubacteria | group of prokaryotes with a wide variety of structures and types of metabolism |
| Excretory system | filters the blood, collects urine, and excretes urine from the body (some textbooks call this the urinary system) |
| Extinction | occurs when the last member of a species dies |
| Food chain | a possible route for the transfer of matter and energy through an ecosystem |
| Food pyramid | summarizes interactions of matter and energy at each trophic level (Some textbooks refer to this as an ecological pyramid.) |
| Food web | shows all the possible feeding relationships in a community |
| Force | a push or pull exerted on an object; has magnitude and direction |
| Fossil fuels | coal, oil, and natural gas formed from the remains of organisms |
| Frequency | in periodic motion, the number of complete oscillations |
| Fungi | group of heterotrophic, eukaryotic consumers that absorb nutrients from decomposing wastes and dead organisms |
| Greenhouse effect | a natural phenomenon by which carbon dioxide and other atmospheric gases prevent heat from escaping into space |
| Heat | energy transferred between objects because of a temperature difference |
| Homeostasis | equilibrium of an organism’s internal environment that maintains conditions suitable for life |
| Host cell | a cell in which a virus reproduces |
| Hypothesis | testable explanation of a question or problem |
| Immune system | protects the body from infections such as the cold and flu |
| Integumentary system | consists of the skin and its associated structures |
| Interference | the interaction of two or more waves |
| Ionic bond | the electrostatic force that holds oppositely charged particles together in an ionic compound |
| Kingdom | taxonomic grouping of related phyla |
| Laboratory safety | biologists try to minimize hazards to themselves, the people working around them, and the organisms they are studying |
| Law of Conservation of Energy | the energy in a closed, isolated system is constant |
| Law of Conservation of Mass | states that, in any process, mass is neither created nor destroyed, but is conserved |
| Lytic cycle | viral reproductive cycle |
| Mechanical advantage | the ratio of resistance force to effort force |
| Metabolism | total of all chemical reactions that occur within a living organism |
| Mitochondrion | eukaryotic membrane-bound organelle in which good molecules are broken down to produce energy |
| Momentum | a property of any moving object; the product of an object’s mass and velocity (p=mv) |
| Muscular/skeletal system | includes three types of muscles: smooth, cardiac, and skeletal; the skeletal system consists of the skeleton |
| Mutation | error or change in the DNA sequence that may affect whole chromosome or just one gene |
| Mutualism | symbiotic relationship beneficial to both species |
| Natural selection | mechanism that explains how changes in populations occur when organisms with favorable variations for a particular environment survive, reproduce, and pass these variations on to the next generation; can be stabilizing, directional or disruptive |
| Nervous system | includes the brain, spinal cord, nerves and sense organs |
| Newton’s First Law | If a system has no net force on it, then its velocity will not change. |
| Newton’s Second Law | Acceleration of an object equals the net force on that object divided by its mass. |
| Newton’s Third Law | All forces come in pairs that are equal in magnitude and opposite in direction. |
| Organelles | internal membrane-bound structures in a cell |
| Oxidation | the loss of electrons from the atoms of a substance |
| Parasitism | symbiotic relationship in which one species benefits at the expense of the other species |
| Period | in periodic motion, the time needed to repeat a complete cycle |
| Permeability | property of a plasma or cell membrane that maintains the cell’s homeostasis (Some textbooks call this selective permeability.) |
| pH scale | the logarithm of the hydrogen ion concentration of a solution |
| Photosynthesis | process by which autotrophs produce simple sugars from water and carbon dioxide using energy absorbed from sunlight |
| Phylogeny | evolutionary history of a species based on comparative relationships of structures and on comparisons of modern life forms with fossils |
| Physical change | a change that alters the physical properties of a substance but not its composition |
| Physical Property | characteristic of a material that can be observed without changing the identity of the material |
| Plants | of stationary, multicellular eukaryotes that photosynthesize |
| Polarization | the action or process of affecting radiation and light so that the vibrations of the waves assume a definite form |
| Power | the rate at which energy is transferred |
| Predation | a mode of life in which food is primarily obtained by the killing and consuming of animals |
| Protists | group of eukaryotic, plantlike, animal-like, or funguslike organisms lacking complex organ systems that live in moist environments |
| Punnett square | a shorthand way of finding the expected proportions of possible genotypes in the offspring of a cross |
| Radiation | the transfer of energy by electromagnetic waves |
| Reflection | occurs when a wave strikes an object and bounces off |
| Refraction | a change in the direction of waves crossing a boundary between two different media |
| Replication | process in which the two strands of the double helix separate and bases pair with free nucleotides to form two molecules of DNA |
| Reproductive system | involved in the production of gametes |
| Resonance | a vibration of large amplitude caused by a relatively small stimulus of a similar period |
| Respiration | process in which cells break down molecules of food to release energy |
| Respiratory system | consists of a pair of lungs, a series of passageways into the body, and a thin sheet of smooth muscle called the diaphragm |
| Retroviruses | viruses containing a unique enzyme, reverse transcriptase, which transcribes viral RNA into DNA, enabling the viral DNA to enter the host cell’s chromosome |
| Ribosomes | eukaryotic organelles involved in protein synthesis |
| RNA | ribonucleic acid; forms a copy of DNA for use in protein synthesis |
| Rock cycle | continuous, dramatic set of processes by which rocks are changed into other types of rock |
| Scientific methods | common procedures used by scientists to gather information used in problem solving and experimentation |
| Solar cell | changes light energy into electric energy (Some textbooks call this a photovoltaic cell.) |
| Solubility | the maximum amount of solute that will dissolve in a given amount of solvent at a specific temperature and pressure |
| Solute | the substance that dissolves |
| Solution | a uniform mixture that may contain solids, liquids, or gases |
| Solvent | the dissolving medium |
| Speciation | the process by which a new species is formed when individuals of a population are unable to interbreed or produce fertile offspring |
| Speed | rate of change in the position of an object (some textbooks call this velocity.) |
| States of matter | the physical forms in which all matter naturally exists—most commonly as a solid, liquid, or a gas |
| Taxonomy | branch of biology dealing with grouping and naming organisms |
| Transcription | the process by which enzymes make an RNA copy of a DNA strand |
| Translation | process in which the bases in mRNA code for amino acids |
| Trophic level | represents a feeding step in the transfer of energy and matter in an ecosystem |
| Universal solvent | Water is commonly called a universal solvent because of its polarity. |
| Valence electrons | the electrons in an atom’s outermost orbitals that determine the chemical properties of an element |
| Variable | a quantity or condition that can have more than one value in a controlled experiment |
| Virus | disease-causing, nonliving particle composed of an inner core of nucleic acid enclosed by one or two protein coats |
| Viscosity | a measure of the resistance of a liquid to flow |
| Water cycle | the sequence through which water passes from the atmosphere through precipitation on land or water surfaces and ultimately back into the atmosphere |
| Wavelength | the shortest distance between points where the wave pattern repeats itself |
| Work | the process of changing the energy of a system by means of forces; the product of the force and the distance over which the force was applied (W=fd) |
