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BCT Terms

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Active site
The site on an enzyme that attaches to a substrate
Aerobic
In the presence of oxygen
Anaerobic
Without oxygen
Autotroph
An organism that produces its own nutrients from inorganic substances or from the environment instead of consuming other organisms
Carbohydrate
Any organic compound that is made of carbon, hydrogen and oxygen and that provides nutrients to the cells of living things
Cellular Respiration
The process by which cells obtain energy from carbohydrates, atmospheric oxygen combines with glucose to form water and carbon dioxide
Cell Theory
The theory that states that all living things are made up of one or more cells, that cells are the basic units of organisms, that each cell in a multicellular organism has a specific job
Chlorophyll
A green pigment that is present in most plant cells, that gives plants their characteristic green color, and that reacts with sunlight, carbon dioxide, and water to form carbohydrates
Cohesion
The force that holds molecules of a single material together
Deletion
The loss of a part of DNA from a chromosome
Diffusion
The movement of particles from regions of higher density to regions of lower density
Enzyme
A type of protein or RNA molecule that speeds up metabolic reactions in plant and animals without being permanently changed or destroyed
Energy pyramid
An ecologic or trophic pyramid. A graphical representation designed to show the biomass or productivity at each trophic level in a given ecosystem
Equilibrium
In biology, a state that exists when the concentration of a substance is the same throughout a space
Heterotroph
An organism that obtains organic food molecules by eating other organisms or their byproducts and that cannot synthesize organic compounds from inorganic material
Hypertonic
Describes a solution whose solute concentration is higher than the solute concentration inside a cell
Hypotonic
Describes a solution whose solute concentration is lower than the solute concentration inside a cell
Lipid
A large, nonpolar organic molecule, including fats ad steroids; lipids store energy and make up cell membranes
Lysogenic
A method of viral replication in which a viral genome is replicated as a provirus without destroying the host cell
Lytic
A method of viral replication that results in the destruction of a host cell and the release of many new virus particles
Osmosis
The diffusion of water or another solvent from a more dilute solution to a more concentrated solution through a membrane that is permeable to the solvent
pH
A range of values that are used to express the acidity or alkalinity of a system; each whole number on the scale indicates a tenfold change in acidity; a pH of 7 is neutral, a pH of less than 7 is acidic; and a pH of greater than 7 is alkaline.
photosynthesis
The process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water to produce carbohydrates and oxygen
protein
An organic compound that is made of one or more chains of amino acids and that is a principal component of all cells
Adaptation
The process of becoming adapted to an environment; an anatomical, physiological, or behavioral trait that improves an organism's ability to survive and reproduce
Adaptive radiation
An evolutionary pattern in which many species evolve from a single ancestral species
Analogous
An anatomical structure in one species that is similar in function and appearance, but not in evolutionary origin, to another anatomical structure in another species
Cladogram
A diagram that is based on patterns of shared, derived straits and that shows the evolutionary relationships between groups of organisms
Convergent evolution
The process by which unrelated species become more similar as they adapt to the same kind of environment
Derived Characteristic
A feature that evolved only within a particular taxonomic group
Divergent Evolution
The process by which two or more related but reproductively isolated populations become more and more dissimilar
Domain
In a modern taxanomic system, the broadest category; the category that contains kingdoms
Evolution
A heritable change in characteristics within a population from one generation to the next; the development of new types of organisms from preexisting types of organisms over time
Extinction
The death of every member of a species
Kingdom
A traditional taxonomic system, the highest taxonomic category which contains a group of similar phyla
Natural Selection
The process by which individuals are better adapted to their environment survive and reproduce more successfully than less well adapted individuals do; a theory to explain the mechanism of evolution
Phylogeny
The evolutionary history of a species or taxonomic group; the relationships of ancestry among species or taxonomic groups
Punctuated Equilibrium
A model of evolution in which short periods of drastic change in species, including mass extinctions and rapid specialization, are separated by long periods of little or no change
Species
A group of organisms that are closely related and can mate to produce fertile offspring; also the level to classification below genus and above subspecies
Taxon
An particular group within a taxonomic system
Taxonomy
The science of describing, naming and classifying organisms
Allele
One of the alternative forms of a gene that governs a characteristic, such as hair color
Chromatid
One of the two strands of a chromosome that becomes visible during meiosis or mitosis
Cross-over
The exchange of genetic material between homologous chromosomes during meiosis; can result in genetic recombination
Dihybrid
A cross between individuals that have different alleles for the same gene
Diploid
A cell that contains two haploid sets of chromosomes
F1 Cross
A cross that yields the first generation of offspring obtained from an experimental cross of two organisms that are both true-breeding
F2 Cross
The second generation of offspring, obtained from an experimental cross of two organisms; the offspring of the F1 generation
Genotype
The entire genetic makeup of an organism; also the combination of genes for one or more specific traits
Haploid
Describes a cell, nucleus, or organism that has only one set of unpaired chromosomes
Heterozygous
Describes an individual that has two different alleles for a trait
Homozygous
Describes an individual that has identical alleles for a trait on both homologous chromosomes
Incomplete Dominance
A condition in which a trait in an individual is intermediate between the phenotype of the individual's two parents because the dominant allele is unable to express itself fully
Karyotype
A micrograph of the array of chromosomes visible in a cell during metaphase; a graphical display that shows an individual's chromosomes arranged in homologous pairs and in order of diminishing size
Nitrogen base
An organic base that contains nitrogen, such as a purine or pyrimidine; a subunit of a nucleotide in DNA and RNA
Nucleotide
In a nucleic-acid chain, a subunit that consists of a sugar, a phosphate, and a nitrogenous base
Pedigree
A diagram that shows the occurrence of a genetic trait in several generations of a family
Phenotype
An organism's appearance or other detectable characteristic that results from the organism's genotype and the environment
Polygenic
Describes a characteristic that is influenced by many genes
Purine
A nitrogenous base that has a double-ring structure; one of the two general categories of nitrogenous bases found in DNA and RNA; either adenine or guanine
Pyrimidine
A nitrogenous base that has a single-ring structure; one of the two general categories of nitrogenous bases found in DNA and RNA; thymine, cytosine or uracil
Recombinant DNA
DNA molecules that are artificially created by combining DNA from different sources
Tetrad
The four chromatids in a pair of homologous chromosomes that come together as a result of synapsis during meiosis
Test-cross
The crossing of an individual of an unknown genotype with a homozygous recessive individual to determine the unknown genotype
Transcription
The process of forming a nucleic acid by using another molecule as a template; particularly the process of synthesizing RNA by using one strand of a DNA molecule as a template
Translation
The portion of protein synthesis that takes place at ribosomes and that uses the codons in mRNA molecules to specify the sequence of amino acids in polypeptide chains
Abiotic factor
An environmental factor that is not associated with the activities of living organisms
Acid rain
Precipitation, such as rain, sleet, or snow, that contains a high concentrations of acids, often because of the pollution of the atmosphere
Biome
A large region characterized by a specific type of climate and certain types of plant and animal communities
Biotic factors
An environmental factor that is associated with or results from the activities of living organisms
Consumer
An organism that eats other organisms or organic matter instead of producing its own nutrients or obtaining nutrients from inorganic sources
Ecosystem
A community of organisms and their abiotic environment
Food Chain
The pathway of energy transfer through various stages as a result of the feeding patterns of series of organisms
Habitat
The place where an organisms usually lives
Niche
The unique position occupied by a species, both in terms of its physical use of its habitat ad its function within an ecological community
Ozone layer
The layer of the atmosphere at an altitude of 15 to 40 km in which ozone absorbs ultraviolet solar radiation
Population
A group of organisms of the same species that live in a specific geographical area and interbreed
Producer
An organism that can make organic molecules from inorganic molecules; a photosynthetic or chemosynthetic autotroph that serves as the basic source in an ecosystem
Water Cycle
The continuous movement of water between the atmosphere, the land and the oceans