Biology Definitions

Question 1

Copies the genetic instructions from DNA in the nucleus, and carries the instructions to the cytoplasm.

Answer 1

Messenger RNA( mRNA )

Question 2

Helps form ribosomes, the organelle where proteins are assembled.

Answer 2

Ribosomal RNA (rRNA )

Question 3

Brings amino acids to ribosomes, where they are joined together to form proteins.

Answer 3

Transfer RNA (tRNA )

Question 4

The addition of nucleotides to the growing mRNA strand.

Answer 4

Elongation

Question 5

The beginning of transcription; occurs when RNA polymerase binds to the promoter of a gene.

Answer 5

Initiation

Question 6

Ending of transcription and occurs when RNA polymerase crosses a stop ( termination ) sequence in the gene.

Answer 6

Termination

Question 7

Group of three nitrogen bases in RNA or DNA that is the genetic code word for a single amino acid or for a start or stop signal.

Answer 7

Codons

Question 8

The three-base frame that divides the bases into codons.

Answer 8

Reading frame

Question 9

Structure found in all cells that is the site of protein synthesis.

Answer 9

Ribosome

Question 10

Nonliving aspect of the environment such as sunlight and water.

Answer 10

Abiotic factors

Question 11

Are the living aspects of the environment. They consist of other organisms, including members of the same and different species.

Answer 11

Biotic factors

Question 12

Two species within the same area coexist and adapt by developing different specializations.

Answer 12

Character displacement

Question 13

Is a relationship between two species, or individuals of the same species, that strive for the same resources in the same place.

Answer 13

Competition

Question 14

An organism that must eat or consume other organisms to obtain energy and nutrients.

Answer 14

Consumer

Question 15

Branch of biology that is the study of how living things interact with each other and with their environment.

Answer 15

Ecology

Question 16

Role that a particular species plays in its ecosystem, including all the ways that the species interacts with the biotic and abiotic factors in the ecosystem.

Answer 16

Niche

Question 17

All the organisms of the same species that live in the same area.

Answer 17

Population

Question 18

Type of organism that uses light energy or chemical energy to make food for itself and other organisms.

Answer 18

Producers

Question 19

Aquatic biome such as a pond, lake, stream, or river in which the water contains little or no salt.

Answer 19

Freshwater biome

Question 20

Predator species that plays a special role in its community because changes in its population affect the population of many species in the community.

Answer 20

Keystone species

Question 21

Interaction between two organisms of unlike species; one organism acts as a predator that captures and feeds on the other organism, which serves as the prey.

Answer 21

Predator-prey relationship

Question 22

A situation in which a species completely dies out and no members remain.

Answer 22

Extinction

Question 23

The relationship between organisms of different species that strive for the same resources in the same place.

Answer 23

Interspecific competition

Question 24

The relationship between organisms of the same species that strive for the same resources in the same place.

Answer 24

Intraspecific competition

Question 25

Close relationship between two species in which at least one species benefits.

Answer 25

Symbiosis

Question 26

Type of species that first colonizes a disturbed area.

Answer 26

Pioneer species

Question 27

Change in the numbers and types of species that live in a community that occurs in an area that has never before been colonized by organisms and lacks soils.

Answer 27

Primary succession

Question 28

Change in the numbers and types of species that live in a community that occurs in an area that has soil and was previously colonized but has been disturbed.

Answer 28

Secondary succession

Question 29

Bar graph that represents the number of individuals of each sex and age ( or age group ) in a population.

Answer 29

Population pyramid

Question 30

Movement of individuals out of a population

Answer 30

Emigration

Question 31

Movement of individuals into a population.

Answer 31

Immigration

Question 32

Regular movement of individuals or populations each year during certain seasons, usually to find food, mates, or other resources.

Answer 32

Migration

Question 33

Organism that makes its own food.

Answer 33

Autotrophs

Question 34

Type of organism that obtains food by breaking down the remains of dead organisms or other organic wastes into its various components, including nutrients that can be used by other organisms.

Answer 34

Decomposers

Question 35

Organism that gets food by consuming other organisms.

Answer 35

Heterptrophs

Question 36

Type of decomposer that consumes dead animals.

Answer 36

Scavengers

Question 37

All the living things in a given area together with the physical and chemical factors of the nonliving environment.

Answer 37

Ecosystem

Question 38

Total mass of organisms at a given trophic level in a food chain or food web.

Answer 38

Biomass

Question 39

An organism's feeding position in a food chain.

Answer 39

Trophic level

Question 40

The evaporation that occurs from the land surface along with transpiration.

Answer 40

Evapotranspiration

Question 41

Release of water vapor into the atmosphere from stomata in the leaves of plants.

Answer 41

Transpiration

Question 42

Process of changing nitrogen gas to nitrates that is carried out by nitrogen-fixing bacteria in the soil or in the roots of legumes.

Answer 42

Nitrogen fixation

Question 43

The variety of life within a particular habitat, often measured by the number of different species.

Answer 43

Biodiversity

Question 44

An area with similar climate that includes similar communities of plants and animals.

Answer 44

Biome

Question 45

Average weather in an area over a long period of time.

Answer 45

Climate

Question 46

Group of similar, land-based ecosystems, such as tropical rain forests, temperate grasslands, or tundras.

Answer 46

Terrestrial biomes

Question 47

Area in a body of water that is deeper than 200 meters where sunlight does not penetrate to allow photosynthesis to take place.

Answer 47

Aphotic zone

Question 48

Water-based biome, or group of similar water-based ecosystems; including freshwater or marine biomes.

Answer 48

Aquatic biomes

Question 49

Aquatic biome in the salt water of the ocean.

Answer 49

Marine biomes

Question 50

Area in a body of water that extends to a maximum depth of 200 meters and where enough sunlight penetrates to allow photosynthesis to take place.

Answer 50

Photic zone

Question 51

Largest population size of a species that can be supported by the environment.

Answer 51

Carrying capacity

Question 52

Individuals that do not have the genetic disorder themselves, but they carry the mutant allele and can pass it to their offspring.

Answer 52

Carriers

Question 53

Monomer of a protein.

Answer 53

Amino acids

Question 54

Doctrine that genetic instructions in DNA are copied by RNA, which carries them to a ribosome where they are used to synthesize a protein ( DNA to RNA to protein )

Answer 54

Central dogma of molecular biology

Question 55

Observations by Erwin Chargaff that concentrations of the four nucleotide bases differ among species; and that, within a species, the concentrations of adenine and thymine are always about the same and the concentrations of cytosine and guanine are always about the same.

Answer 55

Chargaff's rules

Question 56

Relationship between two alleles for the same gene in which both alleles are expressed equally in the phenotype of the heterozygote.

Answer 56

Codominance

Question 57

Double-stranded nucleic acid that stores genetic information; also known as deoxyribonucleic acid.

Answer 57

DNA

Question 58

Double spiral shape of the DNA molecule.

Answer 58

Double Helix

Question 59

Universal code of three-base codons that encodes the genetic instructions for the amino acid sequence of proteins.

Answer 59

Genetic code

Question 60

All of the hereditary information encoded in the DNA of a species.

Answer 60

Genome

Question 61

Organism that inherits two different alleles for a given gene. AKA heterozygous.

Answer 61

Heterozygote

Question 62

International science project that sequenced all 3 billion base pairs of the human genome.

Answer 62

Human Genome Project

Question 63

Relationship between the alleles for a gene in which one allele is only partly dominant to the other allele do an intermediate phenotype results.

Answer 63

Incomplete dominance

Question 64

A change in the sequence of bases in DNA.

Answer 64

Mutations

Question 65

Organic compounds, such as DNA or RNA, that is made of monomers called nucleotides.

Answer 65

Nucleic acid

Question 66

Monomer of nucleic acids; contains a five-carbon sugar, phosphate group, and nitrogenous base.

Answer 66

Nucleotide

Question 67

Characteristics, or trait, controlled by more than one gene, each of which may have two or more alleles.

Answer 67

Polygenic traits

Question 68

Process in which cells make proteins; includes transcription ( DNA to mRNA ) and translation ( mRNA to protein ).

Answer 68

Protein synthesis

Question 69

A single-stranded nucleic acid that helps make proteins.

Answer 69

RNA

Question 70

Process in which genetic instructions in DNA are copied to form a complementary strand of mRNA.

Answer 70

Transcription

Question 71

Containing a gene transferred from another organism.

Answer 71

Transgenic

Question 72

Process in which the genetic code in mRNA is read, one codon at a time, to make a protein.

Answer 72

Translation

Question 73

Traits controlled by a gene located on the X chromosomes.

Answer 73

X-linked traits

Question 74

Energy-requiring movement of molecules across a membrane from a region of lower concentration to a region of higher concentration.

Answer 74

Active transport

Question 75

Any of the alternative forms of a gene that occurs at a specific place on a chromosome.

Answer 75

Allele

Question 76

High energy molecule that contains, within its bonds, energy that cells can use.

Answer 76

ATP

Question 77

Basic unit of life.

Answer 77

Cell

Question 78

Double-layer of phospholipids that forms a boundary between a cell and the surrounding environment and controls the passage of materials into and out of a cell.

Answer 78

Cell membrane

Question 79

Process of producing ATP by breaking down carbon-based molecules when oxygen is present.

Answer 79

Cellular respiration

Question 80

Organelle composed of numerous membranes that are used to convert solar energy into chemical energy; contain chlorophyll.

Answer 80

Chloroplast

Question 81

Long, continuous thread of DNA that consists of numerous genes and regulatory information.

Answer 81

Chromosome

Question 82

Cell that has two copies of each chromosome, one from an egg and one from a sperm.

Answer 82

Diploid

Question 83

Allele that is expressed when two different alleles are present in an organism's genotype.

Answer 83

Dominant

Question 84

Interconnected network of thin, folded membranes that produce, process, and distribute proteins.

Answer 84

Endoplasmic reticulum

Question 85

Protein that catalyzes chemical reactions for organisms.

Answer 85

Enzyme

Question 86

Sex cell; an egg or sperm cell.

Answer 86

Gamete

Question 87

Specific region of DNA that codes for a particular protein.

Answer 87

Gene

Question 88

Cell that has only one copy of each chromosome.

Answer 88

Haploid

Question 89

Regulation and maintenance of constant internal conditions in an organism.

Answer 89

Homeostasis

Question 90

Proposed explanation or answer to a scientific question.

Answer 90

Hypothesis

Question 91

Form of nuclear division that divides a diploid cell into haploid cells; important in forming gametes for sexual reproduction.

Answer 91

Meiosis

Question 92

Bean shaped organelle that supplies energy to the cell and has its own ribosomes and DNA.

Answer 92

Mitochondria

Question 93

Process by which a cell divides its nucleus and contents.

Answer 93

Mitosis

Question 94

Molecular subunit of a polymer.

Answer 94

Monomer

Question 95

Organelle composed of a double membrane that acts as the storehouse for most of a cell's DNA.

Answer 95

Nucleus

Question 96

An individual living thing.

Answer 96

Organism

Question 97

Measurement of acidity; related to free hydrogen ion ( H+ ) concentration in a solution.

Answer 97

pH

Question 98

Process by which light energy is converted to chemical energy; produces sugar and oxygen from carbon dioxide and water.

Answer 98

Photosynthesis

Question 99

Large, carbon based molecule formed by monomers.

Answer 99

Polymer

Question 100

Model for predicting all possible genotypes resulting from a cross, or mating.

Answer 100

Punnett square

Question 101

Allele that is not expressed unless two copies are present in an organism's genotype.

Answer 101

Recessive

Question 102

Condition or quality of allowing some, but not all, materials to cross a barrier or membrane.

Answer 102

Selective permeability

Question 103

Group of organisms so similar to one another that they can breed and produce fertile offspring.

Answer 103

Species