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Flashcards in Workbook1 Deck (171):
1

ecology

scientific study of interactions among organisms and between organisms and their environment

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biosphere

part of Earth in which life exists including land, water, and air or atmosphere

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species

group of similar organisms that can breed and produce fertile offspring

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population

group of individuals of the same species that live in the same area

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community

assemblages of different populations that live together in a defined area

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ecosystem

collection of all the organisms that live in a particular place, together with their nonliving environment

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biome

group of ecosystems that have the same climate and dominant communities

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autotroph

organism that can capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds; also called a producer

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producer

organism that can capture energy from sunlight or chemicals and use it to produce food from inorganic compounds; also called an autotroph

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photosynthesis

process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high,energy carbohydrates such as sugars and starches

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chemosythesis

process by which some organisms, such as certain bacteria, use chemical energy to produce carbohydrates

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heterotroph

organism that obtains energy from the foods it consumes; also called a consumer

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consumer

organism that relies on other organisms for its energy and food supply; also called a heterotroph

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herbivore

organism that obtains energy by eating only plants

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carnivore

organism that obtains energy by eating animals

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omnivore

organism that obtains energy by eating both plants and animals

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detritivore

organism that feeds on plant and animal remains and other dead matter

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decomposer

organism that breaks down and obtains energy from dead organic matter

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food chain

series of steps in an ecosystem in which organisms transfer energy by eating and being eaten

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food web

network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem

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trophic level

step in a food chain or food web

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ecological pyramid

diagram that shows the relative amounts of energy or matter within each trophic level in a food chain or food web

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biomass

total amount of living tissue within a given trophic level

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biogeochemical cycle

process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another

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evaporation

process by which water changes from a liquid into an atmospheric gas

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transpiration

loss of water from a plant through its leaves

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nutrient

chemical substance that an organism requires to live

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nitrogen fixation

process of converting nitrogen gas into ammonia

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denitrification

conversion of nitrates into nitrogen gas

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primary productivity

rate at which organic matter is created by producers in an ecosystem

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limiting nutrient

single nutrient that either is scarce or cycles very slowly, limiting the growth of organisms in an ecosystem

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algal bloom

an immediate increase in the amount of algae and other producers that results from a large input of a limiting nutrient

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accessory pigment

compound other than chlorophyll that absorbs light at different wavelengths than chlorophyll

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eyespot

Group of cells that can detect changes in the amount of light in the environment

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pellicle

Cell membrane in Euglenas

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phytoplankton

population of algae and other small, photosynthetic organisms found near the surface of the ocean and forming part of plankton

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phycobilin

accesory pigment found in red algae that is especially good at absorbing blue light.

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filament

In algae, a long threadlike colony formed by many green algae; in plants, a long, thin structure that supports an anther

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alternation of generations

process in which many algae switch back and forth between haploid and diploid stages of their life cycles

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gametophyte

Haploid, or gamete,producing, phase of an organism

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spore

haploid reproductive cell

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sporophyte

diploid, or spore,producing, phase of an organism

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protist

any eukaryote that is not a plant, an animal, or a fungus

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pseudopod

temporary projection of cytoplasm, or a "false foot," used by some protists for feeding or movement

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amoeboid movement

Type of locomotion used by amoebas

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food vacuole

small cavity in the cytoplasm of protists that temporarily stores food

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cilium

short hairlike projection similar to a flagellum; produces movement in many cells

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trichocyst

small, bottle,shaped structure used for defense by paramecia

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macronucleus

the larger of a ciliate's two nuclei, contains multiple copies of most of the genes that the cell needs in its day,to,day existence

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micronucleus

the smaller of a ciliate's two nuclei; contains a "reserve copy" of all of the cell's genes

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gullet

indentation in one side of a ciliate that allows food to enter the cell

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anal pore

region of the cell membrane of a ciliate where waste,containing food vacuoles fuse and are then emptied into the environment

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contractile vacuole

Cavity in the cytoplasm of some protists that collects water and discharges it from the cell

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conjugation

form of sexual reproduction in which paramecia and some prokaryotes exchange genetic information

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cellular slime mold

slime mold whose individual cells remain separated during every phase of the mold's life cycle

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acellular slime mold

slime mold that passes through a stage in which its cells fuse to form large cells with many nuclei

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fruiting body

slender reproductive structure that produces spores and is found in some funguslike protists; reproductive structure of fungus that develops from a mycelium

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plasmodium

structure with many nuclei formed by acellular slime molds

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hypha

tiny filament that makes up a multicellular fungus or a water mold

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zoosporangium

Spore case

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antheridium

Male reproductive structure in some algae and plants

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oogonium

Specialized structure formed by hyphae that produces female Nuclei

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prokaryote

unicellular organism lacking a nucleus

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bacillus

rod,shaped prokaryote

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coccus

spherical prokaryote

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spirillum

spiral or corkscrew,shaped prokaryote

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chemoheterotroph

organism that must take in organic molecules for both energy and carbon

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photoheterotroph

organism that is photosynthetic but needs organic compounds as a carbon source

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photoautotroph

organism that uses energy from sunlight to convert carbon dioxide and water to carbon compounds

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chemoautotroph

organism that makes organic carbon molecules from carbon dioxide using energy from chemical reactions

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obligate aerobe

organism that requires a constant supply of oxygen in order to live

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obligate anaerobe

organism that cannot live in the presence of oxygen

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facultative anaerobe

organism that can survive with or without oxygen

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binary fission

type of asexual reproduction in which an organism replicates its DNA and divides in half, producing two identical daughter cells

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conjugation

form of sexual reproduction in which paramecia and some prokaryotes exchange genetic information

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endospore

type of spore formed when a bacterium produces a thick internal wall that encloses its DNA and a portion of its cytoplasm

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nitrogen fixation

process of converting nitrogen gas into ammonia

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pathogen

disease,causing agent

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vaccine

a preparation of weakened or killed pathogens

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antibiotic

compound that blocks the growth and reproduction of bacteria

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viriod

Single stranded RNA molecules that have no surrounding capsids that cause disease in plants.

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prion

infectious particles composed of protein with no nucleic acid

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virus

a particle made up of nucleic acid, protein, and in some cases lipids that can replicate only by infecting living cells

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capsid

outer protein coat of a virus

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bacteriophage

virus that infects bacteria

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lytic infection

process in which a virus enters a cell, makes a copy of itself, and causes the cell to burst

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lysogenic infection

process by which a virus embeds its DNA into the DNA of the host cell and is replicated along with the host cell's DNA

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prophage

the viral DNA that is embedded in the host cell's DNA

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retrovirus

virus that contains RNA as its genetic information

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gene pool

combined genetic information of all the members of a particular population

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relative frequency

number of times an allele occurs in a gene pool compared with the number of times other alleles occur

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single,gene trait

trait controlled by a single gene that has two alleles

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polygenic trait

trait controlled by two or more genes

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directional selection

form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve

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stabilizing selection

form of natural selection by which the center of the curve remains in its current position; occurs when individuals near the center of a distribution curve have higher fitness than individuals at either end

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disruptive selection

form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle

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genetic drift

random change in allele frequencies that occurs in small populations

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founder effect

change in allele frequencies as a result of the migration of a small subgroup of a population

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Hardy,Weinberg principle

principle that allele frequencies in a population will remain constant unless one or more factors cause the frequencies to change

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genetic equilibrium

situation in which allele frequencies remain constant

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speciation

formation of new species

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reproductive isolation

separation of species or populations so that they cannot interbreed and produce fertile offspring

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behavioral isolation

form of reproductive isolation in which two populations have differences in courtship rituals or other types of behavior that prevent them from interbreeding

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geographical isolation

form of reproductive isolation in which two populations are separated physically by geographic barriers such as rivers, mountains, or stretches of water

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temporal isolation

form of reproductive isolation in which two populations reproduce at different times

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evolution

change in a kind of organism over time; process by which modern organisms have descended from ancient organisms

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theory

well,tested explanation that unifies a broad range of observations

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fossil

preserved remains or evidence of an ancient organism

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artificial selection

selection by humans for breeding of useful traits from natural variation

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struggle for existence

competition among members of a species for food, living space, and the other necessities of life

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fitness

ability of an organism to survive and reproduce in its environment

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adaptation

inherited characteristic that increases an organism's chance of survival

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survival of the fittest

process by which the individuals that are better suited to their environment survive and reproduce most successfully; also called natural selection

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natural selection

process by which the individuals that are better suited to their environment survive and reproduce most successfully; also called survival of the fittest

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descent with modification

principle that each living species has descended, with changes, from other species over time

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common descent

principle that all living things were derived from common ancestors

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homologous structures

structures that have different mature forms in different organisms but develop from the same embryonic tissues

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vestigial organ

organ that serves no useful function in an organism

119

transformation

process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria

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bacteriophage

kind of virus that infects bacteria

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nucleotide

building block of a nucleic acid (DNA and RNA)

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base pairing

Adenine+ Thymine, Cytosine+ Guanine

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chromatin

long strands of DNA found in the eukaryotic cell nucleus; condense to form chromosomes

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histone

protein molecule around which DNA is tightly coiled in chromatin

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replication

(genetics) the process whereby DNA makes a copy of itself before cell division

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DNA polymerase

enzyme that makes bonds between nucleotides, forming an identical strand of DNA during replication

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gene

sequence of DNA that codes for a protein and thus determines a trait

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mRNA (messenger RNA)

RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell

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rRNA (ribosomal RNA)

type of RNA that makes up the major part of ribosomes

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tRNA (transfer RNA)

type of RNA molecule that transfers amino acids to ribosomes during protein synthesis

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transcription

process in which part of the nucleotide sequence of DNA is copied into a complementary sequence in RNA

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RNA polymerase

enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during transcription

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promoter

region of DNA that indicates to an enzyme where to bind to make RNA

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intron

sequence of DNA that is not involved in coding for a protein

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exon

expressed sequence of DNA; codes for a protein

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codon

three,nucleotide sequence on messenger RNA that codes for a single amino acid

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translation

decoding of a mRNA message into a polypeptide chain

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anticodon

group of three bases on a tRNA molecule that are complementary to an mRNA codon

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mutation

a change or alteration in form or qualities

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point mutation

gene mutation involving changes in one or a few nucleotides

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frameshift mutation

mutation that shifts the "reading" frame of the genetic message by inserting or deleting a nucleotide

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polyploidy

condition in which an organism has extra sets of chromosomes

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sex,linked genes

genes found on the chromosomes that determine sex, XX= female, XY= male

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nondisjunction

occurs in meiosis when homologous chromosomes fail to separate

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homologous

term used to refer to chromosomes that each have a corresponding chromosome from the opposite,sex parent

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diploid

term used to refer to a cell that contains both sets of homologous chromosomes

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haploid

term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes

148

meiosis

process by which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell

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tetrad

structure containing 4 chromatids that forms during meiosis

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crossing,over

process in which homologous chromosomes exchange portions of their chromatids during meiosis

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cell division

process by which a cell divides into two new daughter cells

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mitosis

part of eukaryotic cell division during which the cell nucleus divides

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cytokinesis

division of the cytoplasm during cell division

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chromatid

one of two identical "sister" parts of a duplicated chromosome

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centromere

area where the chromatids of a chromosome are attached

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interphase

period of the cell cycle between cell divisions

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cell cycle

series of events that cells go through as they grow and divide

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prophase

first and longest phase of mitosis, during which the chromosomes become visible and the centrioles separate and take up positions on the opposite sides of the nucleus

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centriole

one of two tiny structures located in the cytoplasm of animal cells near the nuclear envelope

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spindle

fanlike microtubule structure that helps separate the chromosomes during mitosis

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metaphase

second phase of mitosis, during which the chromosomes line up across the center of the cell

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anaphase

the third phase of mitosis, during which the chromosome pairs separate and move toward opposite poles

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telophase

fourth and final phase of mitosis, during which the chromosomes begin to disperse into a tangle of dense material

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cyclin

one of a family of closely related proteins that regulate the cell cycle in eukaryotic cells

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cancer

disorder in which some of the body's own cells lose the ability to control growth

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homologous

term used to refer to chromosomes that each have a corresponding chromosome from the opposite,sex parent

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diploid

term used to refer to a cell that contains both sets of homologous chromosomes

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haploid

term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes

169

meiosis

process by which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell

170

tetrad

structure containing 4 chromatids that forms during meiosis

171

crossing,over

process in which homologous chromosomes exchange portions of their chromatids during meiosis