Biology Dictionary

Created by Kathryn Rainelle Cornish

Acid Rain

Definition: Rain containing acids that form in the atmosphere

Supporting Facts: When industrial gas discharge such as sulfur dioxide and nitrogen oxides combine with water it creates biologically harmful rain that is caused by pollutants released by human activity

Related Words: Rain, snow, sleet, fog, acid precipitation

Active Immunity

Definition: A form of developed immunity in which the body produces its own antibodies against disease-causing antigens

Supporting Facts: Occurs when a person is exposed to a live pathogen and triggers the immune system to produce antibodies

Related Words: Acquired immunity, passive immunity

Active Transport

Definition: A movement of a substance such as a protein across a membrane into a region with higher concentration

Supporting Facts: This action requires energy and the energy is supplied through respiration using ATP

Related Words: Transport, ATP, cell membrane


Definition: A change by which makes an organism better suited to live and reproduce in their environment

Supporting Facts: Describes how organisms change over time in response to the environmental change around them

Related Words: Adjustment


Definition: One of the forms of a gene that codes for a particular trait

Supporting Facts: Punnett squares have alleles of one parent along the top and side of the square, alleles are seen in the hardy-weinberg equation, alleles are a part of recessive and dominant traits

Related Words: Genotype, phenotype

Amino Acids

Definition: The basic building blocks of proteins

Supporting Facts: A large proportion of our cells, muscles, and tissues is made up of amino acids

Related Words: Enzyme, codon

Anaerobic Respiration

Definition: A form of cellular respiration when oxygen is absent or scarce

Supporting Facts: Sometimes there isn't enough oxygen around plants and animals for them to breathe. In order to survive they carry out respiration in the absence of oxygen to produce energy. Only a small amount of energy is released

Related Words: Aerobic respiration, cellular respiration

Animal Cell

Definition: A eukaryotic cell in which all the organelles are contained in membranes

Supporting Facts: Animal cells are multicellular and are surrounded by plasma membrane

Related Words: Plant cell


Definition: A chemical that kills bacteria or slows its growth

Supporting Facts: Antibiotics are borrowed from microorganisms such as bacteria or fungi

Related Words: Virus, infection, bacteria


Definition: A molecule that causes an immune response

Supporting Facts: Helps produce antibodies againtst the pathogen invading the body

Related Words: Antibody, immune system

Asexual Reproduction

Definition: A type of reproduction by which offspring results from a single organism

Supporting Facts: Is a copy of parent and only has one parent

Related Words: sexual reproduction, reproduction


Definition: A nucleotide borrowed from adenosine that occurs in muscle tissue; the major source of energy for cellular reactions

Supporting Facts: Also known as biological energy and is the reusable form of energy in your cells

Related Words: Adenosine triphosphate,


Definition: An organism that can nourish itself by using inorganic nutrients materials for nutrients or from photosynthesis

Supporting Facts: Sulfur bacteria uses H2S to help make their food instead of using water. They oxidize the H2S into sulfate so they can use it to make food

Related Words: Heterotroph


Definition: Single celled microscopic organism

Supporting Facts: Bacteria can cause sicknesses in organisms, some bacteria can be good

Related Words: Pathogen

Behavioral Adaptations

Definition: When an organism changes it pattern or action to better suit its environment

Supporting Facts: Behaviors are not always inherited but they are learned. For example wild birds will flee from humans, but birds in cities see humans as a source for food. This trait is learned not inherited.

Related Words: Structural adaptation


Definition: The build up of chemicals in an organism

Supporting Facts: Is a threat of the organisms health and the environment

Related Words: Bioconcentration, biological magnification

Biochemical Similarities (evolution)

Definition: Observation that the basic biochemical processes of all organisms are very similar

Supporting Facts: The genetic code of all life on Earth is written in the same chemical building blocks

Related Words: Comparative embryology, comparative anatomy


Definition: All of the different species in an area

Supporting Facts: Biodiversity can be an important indicator in how healthy and well functioning an ecosystem is

Related Words: Genetic diversity, species diversity, ecosystem diversity


Definition: A large area dominated by specific organisms

Supporting Facts: The biome is biggest level of ecological classification within the biosphere

Related Words: Ecosphere, ecosystem, habitat


Definition: Use of living organisms to make or develop products

Supporting Facts: Developing crops with enhanced nutrition that solves vitamin and nutrient deficiencies is an example because you are taking a living organism and making it do what you want it to. In this case you are taking a crop and making it solve vitamin and nutrient deficiencies.

Related Words: Biochemistry

Birth Rate

Definition: The proportion of births to the total population in a place in a given time

Supporting Facts: Expressed per 1000 population per year

Related Words: Death rate, fertility rate


Definition: A form of asexual reproduction in plants

Supporting Facts: Identical to its parent, buds may be produced anywhere on the plant or only in a specialized part of the plant

Related Words: Bud grafting, reproduction


Definition: The use of biological coloration to disguise location, identity, and movement from prey. Used as protection from predators.

Supporting Facts: Animals use the background of the environment to blend in such as a green snake would in grass

Related Words: Concealing coloration, background matching, countershading


Definition: An organic compound made of carbon, hydrogen, and oxygen

Supporting Facts: The energy stores in most animals are carbohydrates

Related Words: Glucose, lactose

Carbon Cycle

Definition: Circulation of carbon in different forms through nature

Supporting Facts: The source of carbon found in living things are called carbon dioxide and contribute to the carbon cycle

Related Words: Fossil fuel

Carrying Capacity

Definition: The average population size of a species

Supporting Facts: Carrying capacity is different in each species because of the food, shelter, and social requirements

Related Words: Population


Definition: Membrane bound structure that contains the fundamental molecules of life and what all living things are made of

Supporting Facts: A single cell such as bacteria or yeast is a complete organism itself

Related Words: Cell cycle, membrane

Cell Cycle

Definition: The ordered events that take place in a cell in preparation for cell division

Supporting Facts: The cycle is a four stage process in which cells increase in size, copies its DNA, prepares to divide, and divides

Related Words: Mitosis, Meiosis

Cell Differentiation

Definition: When cells produce other cells that are different from themselves

Supporting Facts: Usually produced for a specialized purpose. One cell performs a different function on your body than another cell would, depending where on the body. Your lung cells have different functions than your brain cells.

Related Words: Cell division

Cell Wall

Definition: Made out of cellulose and is tough and rigid; its purpose is to protect and support the cell

Supporting Facts: Cell walls are found in plants

Related Words: Cell membrane, cytoplasm

Cellular Respiration

Definition: The process of when organisms use oxygen to break down food particles to get chemical energy for cell functions

Supporting Facts: Cellular respiration takes place in the cells of animals, plants, fungi, and also other protists

Related Words: Aerobic respiration, protist


Definition: A basic structural component of cell walls

Supporting Facts: A complex carbohydrate consisting 3,000 or more glucose units

Related Words: Oxycellulose


Definition: Short for the compound chlorofluorocarbon

Supporting Facts: Contains carbon, chlorine, and fluorine; used for refrigeration; can lead to ozone depletion

Related Words: ozone layer

Charles Darwin

Definition: The man that developed a theory of evolution to explain biological change

Supporting Facts: Believed that all species developed from common ancestors and believed that species survived through a process called "natural selection"

Related Words: Alfred Russel Wallace, natural selection, evolutionary tree

Chemical Energy

Definition: Energy in a substance that is released by a chemical reaction

Supporting Facts: Our bodies use chemical energy to perform daily functions

Related Words: Energy, free energy


Definition: A plastid containing chlorophyll

Supporting Facts: Photosynthesis takes place in the chloroplast

Related Words: Chlorophyll


Definition: The two strands that join together during the early stages of cell division

Supporting Facts: They separate completely during a later stage and then in an even later stage it becomes a daughter chromosome

Related Words: Sister chromatids, homologous chromosomes


Definition: Protein found in the nucleus of the cell that contains genetic information

Supporting Facts: In humans each chromosome contains 23 pairs of chromosomes, for a total of 46

Related Words: Centromere, gene, chromatid

Classical Conditioning

Definition: When an organism learns through finding associations between different events and stimuli

Supporting Facts: Classical conditioning happens when a neutral stimulus is paired with an unconditional stimulus

Related Words: Neutral stimulus, unconditional stimulus, conditioned response, unconditioned response


Definition: The processes of sorting things into groups according to shared qualities or characteristics

Supporting Facts: Living things were classified into six groups: kingdom, phylum, class, order, family, and genus and species

Related Words: Modern classification, taxonomy

Climate Change

Definition: A change in global or regional temperature patterns

Supporting Facts: Oceans warming and becoming more acidic, icebergs melting, and ocean levels rising are all proof that the earth is warming

Related Words: Climate feedback, climate lag


Definition: The process of creating a genetically identical individual

Supporting Facts: Clones are not always identical. They're genetically the same but the environment plays an important role in how the organism turns out.

Related Words: Reproduction, twin


Definition: Two alleles of a gene pair in a heterozygote that are both fully expressed

Supporting Facts: When alleles from a white and red flower are present their offspring would be pink because both alleles are codominant

Related Words: Dominant, alleles, recessive

Codon Chart

Definition: Chart with amino acid sequences

Supporting Facts: If you look at the chart is shows three letters which are the nucleotides and it will encode a specific amino acid

Related Words: Purine, start codon, stop codon


Definition: The process that happens when two species influence each other during evolution

Supporting Facts: For example prey may develop camouflage techniques which may make predators progressively better at finding them

Related Words: Evolution


Definition: An association between two organisms which one benefits but the other does not benefit nor harm

Supporting Facts: The organism benefiting may gain food supply or shelter

Related Words: Mutualism, symbiosis


Definition: Negative interaction that occurs between two or more organisms whenever they both require the same living requirements

Supporting Facts: Organisms have competition with food, shelter, mates, etc.

Related Words: Natural selection, intraspecific, interspecific


Definition: Protection of plants, animals, and natural resources

Supporting Facts: An example of conservation is cutting your water footprint can help save fresh water ecosystems such as the Colorado River

Related Words: Conservation biology, ecosystem


Definition: Consumers are apart of the ecological food chain that receives energy by consuming other organisms

Supporting Facts: Consumers are above producers on the food chain or pyramid

Related Words: Producer, trophic level, secondary consumers

Convergent Evolution

Definition: The process where organisms that aren't closely related independently evolve similar traits as the result of having to adapt to similar environments or niches

Supporting Facts: Is the opposite from divergent evolution where organisms evolve different traits

Related Words: Divergent evolution, biological evolution, speciation


Definition: The mutual attraction between two individuals of the opposite sex

Supporting Facts: Courtship is important because it helps to ensure that breeding will occur

Related Words: Couple, estrus, offspring, reproduction

Crossing Over

Definition: The exchange of genes between homologous chromosomes and results in a mixture of characteristics from both parents in the offspring

Supporting Facts: The whole effect of crossing over is to provide variety to the population

Related Words: Recombination, chiasma, gametes


Definition: A chemical that has been used to control mosquitoes that carry malaria. It's toxic to birds, top level predators and the environment itself.

Supporting Facts: Some strains of the insects have become resistant to the DDT

Related Words: PCB

Death Rate

Definition: Number of deaths per unit usually 1000 of a population at a given time

Supporting Facts: Death rate is an important factor when controlling the population

Related Words: Birth rate


Definition: Consumers such as fungi and bacteria that break down dead organic matter for energy

Supporting Facts: Decomposers are important because without them breaking down earths matter the dead bodies of animals would just pile up. The soil also wouldn't be as rich

Related Words: Consumers, producers, scavengers


Definition: The process of rotting or decaying

Supporting Facts: Knowing decomposition can help us take better care of our environment because a plastic bag can take 20 to 1,000 years to decompose since it's not organic.

Related Words: Fermentation, dissolution


Definition: The act of cutting down trees and clearing land

Supporting Facts: It affects to ecosystem each time we cut down trees leaving many organisms and species homeless. Agriculture is the main cause of deforestation.

Related Words: Agriculture

Deletions (mutations)

Definition: Mutation in which part of a chromosome breaks off and is lost

Supporting Facts: Causes of this could be because of unequal crossing over, breaking without rejoining, losses from translocation, and chromosomal crossovers within a chromosomal inversion

Related Words: Mutations, deficiency, mutation


Definition: The process of folding the structure of a protein is altered by a chemical or physical factors causing the protein to be biologically inactive

Supporting Facts: Changes in pH affect the chemistry of amino acids

Related Words: Hydrogen bonding

Dichtomous Keys

Definition: Is a tool that allows the user to determine the identity of items in the natural world

Supporting Facts: Keys consists of series of choices that lead the user to the correct name of a given item

Related Words: Polytomous key


Definition: The biotic and abiotic factors in an area

Supporting Facts: The tropical rain forest is an ecosystem because it contains the living things such as trees and monkeys as well as the nonliving things such as the rocks and rain(water)

Related Words: Community, population, environment, habitat

Energy Pyramid

Definition: A representation of the amount of energy available at different trophic levels in the ecosystem

Supporting Facts: Only ten percent of energy is passed on to the next trophic level in this pyramid

Related Words: Food chain, food web


Definition: Proteins that speed up the chemical reactions that make life possible

Supporting Facts: They reduce the activation energy

Related Words: Active site

Food Chain

Definition: The path of energy flow in organisms

Supporting Facts: The arrows indicate the energy that is being passed on

Related Words: Food web

Food Web

Definition: The picture that shows all the food chains in the ecosystem and how they all relate to each other

Supporting Facts: The food web always starts off with the sun because that's the main energy source

Related Words: Food chain

Fossil Fuels

Definition: A natural fuel such as coal or gas formed from the remains of living organisms

Supporting Facts: Is a source of non renewable energy

Related Words: Renewable energy


Definition: A reproductive cell that can combine with another reproductive cell during fertilization to produce a zygote

Supporting Facts: Are produced by meiosis

Related Words: Diploid cell, haploid cell, fertilization


Definition: A combination of alleles for a trait or an organisms whole set of alleles

Supporting Facts: An individuals genotype adds to the entire complex of genes passed down from both parents

Related Words: Phenotype, allele


Definition: A long chain of molecules that has many branches in the form of which animals store carbohydrates

Supporting Facts: Occurs mainly in the liver and muscle tissue and is easily converted to glucose

Related Words: Cellulose, starch, maltose


Definition: A chromosome that only has half the number of chromosome for that species

Supporting Facts: Reproductive cells are usually haploid cells

Related Words: Diploid, gamete


Definition: A protein in red blood cells that brings oxygen from the lungs to cells

Supporting Facts: Having less hemoglobin can lead to anemia because hemoglobin is in red blood cells that contain iron as well and having less of that will cause anemia because of the lack of iron

Related Words: Plasma


Definition: A system that regulates its internal environment and tends to remain stable

Supporting Facts: Involves controlling the balance of water and minerals in the body

Related Words: Equilibrium


Definition: The process of a young animal perceives another for being its parent and follows that animal around; usually around birth

Supporting Facts: Type of automatic learning

Related Words: innate behavior

Innate behavior

Definition: Behaviors you are born with

Supporting Facts: Crying for humans is an innate behavior because it's an automatic reaction when exposed to a stimulus

Related Words: Learned behavior


Definition: Hormone produced in the pancreas and controls the glucose in ones blood

Supporting Facts: The lack of insulin causes a form of diabetes

Related Words: Diabetes


Definition: Yellowing of skin and white of the eyes caused by liver disease

Supporting Facts: Happens when the elevated levels of bilirubin builds up in the blood

Related Words: Neonatal jaundice


Definition: A photograph that displays an individual's paired homologous chromosomes

Supporting Facts: In order to get this picture the chromosomes are isolated, stained, and viewed under the microscope

Related Words: Karyoplast


Definition: A fast growing Japanese climbing vine

Supporting Facts: The growing problem of this plant is that it can cause environmental concerns since it affects the soil around it

Related Words: Soil productivity

Learned Behaviors

Definition: Acquired changes in behavior during one's lifetime

Supporting Facts: Animals such as monkeys can develop learned behaviors by observation

Related Words: Insight learning, innate behavior

Limited Resources

Definition: Natural resources that will eventually run out as time goes by; may be replenished but can take thousands of years before they are renewed

Supporting Facts: Coal is an example of a limited resource because it's naturally available in certain parts of the Earth. Coal is formed by decomposing organisms that are compacted.

Related Words: Natural resource, fossil fuels


Definition: Naturally occurring molecules that are waxes, fats, cholesterol, and fat-soluble vitamins

Supporting Facts: Provides a source and store of energy and is an important part of the membrane that surrounds every cell

Related Words: Fats, fatty acids, steroids


Definition: Results in the four daughter cells with half of the genetic code of the parent cell for the production of gametes

Supporting Facts: Meiosis is in sexual reproduction

Related Words: Mitosis


Definition: The movement in populations, groups, or individuals

Supporting Facts: Migration helps organisms to get better conditioning for living

Related Words: Behavior, stimulus


Definition: Duplication of a cell and all of its parts it duplicates along with its DNA and the 2 daughter cells that have the same genetic code

Supporting Facts: For asexual reproduction

Related Words: Meiosis

Natural Selection

Definition: Process where an organisms heritable traits increases that organisms chance for surviving and reproducing than it would for non-favorable traits

Supporting Facts: Natural selection helps the next generation thrive

Related Words: Evolution


Definition: The specific area where an organism lives

Supporting Facts: Niche shows the relationship between the organism and it's habitat

Related Words: Habitat, ecosystem


Definition: The process of obtaining or providing the nutrients for growth and development as well as energy

Supporting Facts: Good nutrition will help you develop much better and have more energy than a person with poor nutrition

Related Words: Fermentation, Digestion


Definition: Diffusion of a solvent through a membrane from an area of low concentration to an area of high concentration

Supporting Facts: Water will naturally move from an area with a lower concentration of solutes to a higher concentration to achieve equilibrium

Related Words: Equilibrium, concentration, solutes


Definition: The relationship between two organisms where one of them benefits from the other by causing damage to it

Supporting Facts: An example of parasitism would be a tick feeding off of a dog

Related Words: Host, parasite, predation


Definition: A bacteria or virus that can cause a disease

Supporting Facts: Pathogen transmission involves escape from the host, travel to, and infect the new host

Related Words: Bacteria, viruses


Definition: A type of symbolic relationship between two unlike species where one preys on the other

Supporting Facts: Predation is important because it can be a method of population control

Related Words: Symbolic relationship, mutualism

Quadriceps femoris

Definition: Large muscle group that indicates the four common muscles on the front of the thigh

Supporting Facts: When the quadriceps femoris contracts your leg straightens

Related Words: Femur, patella


Definition: A gene that gets taken over by the dominate gene

Supporting Facts: Recessive traits aren't shown because it is masked by the dominate gene

Related Words: Gene, traits, dominate

Renewable resource

Definition: A source of economic value that can be replenished or replaced in a certain amount of time

Supporting Facts: Solar energy, biomass, and oxygen are all examples of renewable sources

Related Words: Non renewable sources


Definition: The protein builder of the cell

Supporting Facts: Connect the amino acids one strand at a time to build long chains

Related Words: RNA, organelle, protein synthesis, enzyme


Definition: A group of individuals that are closely similar to each other and can produce fertile offspring.

Supporting Facts: Horses and zebras are different species because their offspring's are sterile not able to produce fertile offspring

Related Words: Family, genus


Definition: Spores are single-celled reproductive unit of non flowering plants, bacteria, fungi, and algae

Supporting Facts: Are made to grow a new plant and just needs a thriving environment to grow in

Related Words: Sporogenesis, ovule


Definition: The course of change in the species habitat of an ecological community over time

Supporting Facts: The development that takes place during any form of succession depends on a combination of different factors such as soil moisture, temperature, and wind

Related Words: Climax community, secondary succession, primary succession


Definition: The science of identifying, naming, and classifying living things

Supporting Facts: Organisms are classified by their shared characteristics with other organisms

Related Words: Phylogeny, nomenclature


Definition: The components of an organism

Supporting Facts: Traits are eye color, freckles, skin color, hair type, height, etc.

Related Words: Phenotype


Definition: The process where ribosomes create proteins

Supporting Facts: In translation the messenger RNA also known as mRNA. produced by transcription of DNA, is decoded by a ribosome to create an amino acid

Related Words: Transcription


Definition: A single cell

Supporting Facts: Pertains to an organisms functions that are carried out by one cell such as bacteria and algae

Related Words: Multi-cellular


Definition: A substance used to stimulate the making of antibodies and provide immunity of diseases

Supporting Facts: Created to act as an antigen in your body without including the disease

Related Words: Disease, virus, antigen, pathogen


Definition: Fluid filled space in the cells cytoplasm that performs many functions depending on the cells requirements

Supporting Facts: Keeps everything bad separate from the cell

Related Words: Cytoplasm, lysosome, smooth ER


Definition: Singe stand of DNA or RNA that often causes disease in an organism

Supporting Facts: Not all viruses cause disease and can only replicate with a host cell

Related Words: Bacteria, pathogen, disease

Water Runoff

Definition: Water that drains or flows off of a surface

Supporting Facts: Plays a major part of the water cycle because it's another source of how water would come back to the ground

Related Words: Rainfall, slope, erosion

Watson and Crick

Definition: The two men who discovered the DNA structure

Supporting Facts: Highlighted a milestone in the history of science and created the birth of molecular biology that focuses on the knowledge of how genes control the chemical change within a cell

Related Words: RNA, double-helix

X chromosome

Definition: A chromosome that determines the sex of a human or another mammal and occurs in males and females

Supporting Facts: Two x chromosomes are needed for a girl (XX). One x is needed for a male (XY)

Related Words: Y chromosome


Definition: A tissue in a plant transplants water and nutrients from the root upwards

Supporting Facts: Water and nutrients move up the plant while the sugars move down to the roots

Related Words: Phloem, vascular plants

Y chromosome

Definition: A chromosome that determines the sex of a human or of another animal and only occurs in the males

Supporting Facts: The Y chromosome is always paired matched with the X chromosome

Related Words: X chromosome


Definition: The zygote is the fertilized egg cell from the egg and the sperm cell colliding

Supporting Facts: Is the first stage in development of the genetically unique offspring

Related Words: Embryo, egg cell, sperm cell