Biology Sat Subject Test Vocabulary Flashcards
abiotic
nonliving, as in the physical environment
absorption
the process by which water and dissolved substances pass through a membrane
acetylcholine
a transmitter substance released from the axons of nerve cells at the synapse
active immunity
protective immunity to a disease in which the individual produces antibodies as a result of previous exposure to the antigen
adaptation
a behavioral or biological change that enables an organism to adjust to its environment
adaptive radiation
the production of a number of different species from a single ancestral species
adenosine phosphate
adenosine diphosphate (ADP) and adenosine triphosphate (ATP), which are energy storage molecules
ADH (vassopressin)
a hormone that regulates water reabsorption
adrenal cortex
the ourter part of the adrenal gland that secretes many hormones, including cortisone and aldosterone
adrenal medulla
the inner part of the adrenal gland that secretes adrenalin
adrenaline (epinephrin)
an “emergency” hormone stimulated by anger or fear; increase blood pressure and heart rate in order to supply the emergency needs of the muscles
adrenocorticotrophic hormone
usually referred to as ACTH and secreted by the anterior lobe of the pituitary gland; stimulates the adrenal cortex to produce its characteristic hormones
aerobe
an organism that requires oxygen for respiration and can live only in the presence of oxygen
aerobic
requiring free oxygen from the atmosphere for normal activity and respiration
aldosterone
hormone active in osmoregulation; a mineral corticoid produced by the adrenal cortex; stimulates reabsorption of Na+ and secretion of K+
alimentary canal
an organ centrally involved in the human digestive system
allantois
the extraembyonic membrane of birds, reptiles and mammals that serves as an area of gaseous exchange and as a site for the storage of noxious excretion products
allele
one or two or more types of genes, each representing a particular trait; many alleles exist for a specific gene locus
alternation of generations
the description of a plant life cycle that consists of a diploid, asexual, sporophyte generation and a haploid, sexual, gametrophyte generation
alveolus
an air sac in the lung; the site of respiratory exchange, involving diffusion of oxygen and carbon dioxide between the air in the alveolus and the blood in the capillaries
amnion
the extraembryonic membrane in birds, reptiles and mammals that surrounds the embryo, forming an amniotic sac
pseudopod
movement of amoeba
anaerobe
an organism that does not require free oxygen in order to respire
anaerobic
living or active in the absence of free oxygen; pertaining to respiration that is independent of oxygen
analogous
describes structures that have similar function but different evolutionary origins; e.g., a bird’s wing and a moth’s wing
anaphase
the stage in mitosis that is characterized by the migration of chromatids to opposite ends of the cell; the stage in meiosis during which homologus pairs migrate (Anaphase I), and the stage in meiosis during which chromatids migrate to different ends of the cell (Anaphase II)
Anaphase I
the stage in meiosis during which homologus pairs migrate
AnaphaseII
the stage in meiosis during which chromatids migrate to different ends of the cell
androgen
a mall sex hormone (e.g., testosterone)
angiosperm
a flowering plant; a plant of the class Angiospermae that produces seeds enclosed in an ovary and is characterized by the possession of fruits and flowers
Annelida
the phylum to which segmented worms belong
anther
the part of the male reproductive organ (the stamen) that produces and stores pollen
antibiotic
an antipathogenic substance (e.g., penicillin)
antibody
globular proteins produced by tissues that destroy or inactivate antigens
antigen
a foreign protein that stimulates the production of antibodies when introduced into the body of an organism
aorta
the largest artery; carries blood from the left ventricle
aortic arch
blood vessels located between ascending and descending aortas that deliver blood to most of the upper body
appendage
a structure that extends from the trunk of an organism and is capable of active movements
aqueous humor
fluid in the eye, found between the cornea and the lens
Arachnida
a class of arthropods that includes scorpions, spiders, mites and ticks
artery
a blood vessel that carries blood away from the heart
Arthropoda
the phylum to which jointed-legged invertebrates belong, including insects, arachnids and crustaceans
asexual reproduction
the production of daughter cells by means other than the sexual union of gametes (as in budding and binary fission)
assimilation
the conversion of digested foods and other materials into forms usable by the body (i.e., the conversion of amino acids into proteins)
assortative mating
the type of mating that occurs when an organism selects a mating partner that resembles itself
atrium
the thin-walled anterior chamber of the heart (also called the auricle)
autolysis
self-digestion occurring in plant and animal tissues, particularly after they have ceased to function properly
autonomic nervous system
the part of the nervous system that regulates the involuntary muscles, such as the walls of the alimentary canal; includes the parasympathetic and sympathetic nervous systems
autosome
any chromosome that is not a sex chromosome
autotroph
an organism that utilizes the energy of inorganic materials such as water and carbon dioxide or the sun to manufacture organic materials
auxin
a plant growth hormone
axon
a nerve fiber
bacillus
bacteria that are rod shaped
bacteriophage
a type of virus that can destroy bacteria by infecting, parasitizing and eventually killing them
bile
an emulsifying agent secreted by the liver
bile salts
compounds in bile that aid in emulsification
binary fission
asexual reproduction; in this process, the parent organism splits into two equal daughter cells
binomial nomenclature
the system of naming an organism by its genus and species name
biome
a habitat zone, such as desert, grassland or tundra
biotic
living, as in living organisms in the environment
blastula
a stage of embryonic development in which the embryo consists of a hollow ball of cells
Bowman’s capsule
part of the nephron in the kidney; involved in excretion
bud
in plants, an area of undifferentiated tissue covered by embryonic leaves
budding
a process of asexual reproduction in which the offspring develop from an outgrowth of the plant or animal
buffer
a substance that prevents appreciable changes in pH in solutions to which small quantities of acids or bases are added
calorie
a unit of heat; the amount of heat required to raise the temperature of one gram of water by one degree centigrade
Calvin cycle
cycle in photosynthesis that reduces fixed carbon to carbohydrates through the addition of electrons (“dark cycle”)
cambium
undifferentiated tissue in the stem of a plant that aids growth in width
capillary
a tube one cell thick that carries blood from artery to vein; the site of material exchange between the blood and tissues of the body
carapace
a bony or chitinous case or shield covering the back or part of the back of an animal (shell of a crab)
carbohydrate
an organic compound to which hydrogen and oxygen are attached; the hydrogen and oxygen are in a 2:1 ratio; examples include sugars, starches and cellulose
carbon cycle
the recycling of carbon from decaying organisms for use in future generations
carnivore
a flesh-eating animal; a holotrophic animal that subsists on other animals or parts of animals
cation
an ion with a positive charge, or an ion that migrates towards the cathode (negative electrode) in an electric field
cell wall
a wall composed of cellulose that is external to the cell membrane in plants; it is primarily involved in support and in the maintenance of proper internal pressure
cell wall plate
in mitosis of higher plants, the structure that forms between the divided nuclei of the two daughter cells and eventually becomes the cell wall
central nervous system
encompasses the brain and the spinal cord
centriole
the small granular body within the centrosome to which the spindle fibers attach
centromere
the place of attachment of the mitotic fiber to the chromosome
centrosome
a structure in animal cells containing centrioles from which the spindle fibers develop
cephalic
pertaining to the head
cerebellum
the hindbrain region that controls equilibrium and muscular coordination
cerebral cortex
the outer layer of cerebral hemispheres in the forebrain, consisting of gray matter
cerebral hemisphere
one of the paired lateral divisions of the forebrain
cerebrum
the largest portion of the human brain; it is believed to be the center of intelligence, conscious thought and sensation
chemosynthesis
the process by which carbohydrates are formed through chemical energy; found in bacteria
chemotropism
the orientation of cells or organisms in relation to chemical stimuli; the growth or movement response of organisms to chemical stimuli
chitin
a white or colorless, amorphous, horny substance that forms part of the outer integument of insects, crustaceans and some other invertebrates; it also occurs in certain fungi
chlorophyll
a green pigment that performs essential functions as an electron donor and light “entrapper” in photosynthesis
chloroplast
a plastid containing chlorophyll
Chordata
an animal phylum in which all members have a notochord, dorsal nerve cord and pharyngeal gill slits at some embryonic stage; includes the Cephalochordata and the Vertebrates
chorion
the outermost, extra-embryonic membrane of reptiles and birds
chromatid
one of the two strands that constitute a chromosome; chromatids are held together by the centromere
chromatin
a nuclear protein of chromosomes that stains readily
chromosome
a short, stubby rod consisting of chromatin that is found in the nucleus of the cells; contains the genetic or hereditary component of cells (in the form of genes)
chyme
partially digested food in the stomach
circadian rhythms
daily cycles of behavior
cleavage
the division in animal cell cytoplasm caused by the pinching in of the cell membrane
climax community
the stable, biotic part of the ecosystem in which populations exist in balance with each other and with the environment
clotting
the coagulation of blood caused by the rupture of platelets and the interaction of fibrin, fibrinogen, thrombin, prothrombin and calcium ions
cloaca
the chamber in the alimentary canal of certain vertebrates located below the large intestine, into which the ureter and reproductive organs empty (as in frogs)
cochlea
the sensory organ of the inner ear of mammals; it is coiled and contains the organ of corti
codominant
the state in which two genetic traits are fully expressed and neither dominates
Coelentrata
an invertebrate animal phylum in which animals possess a single alimentary opening and tentacles with stinging cells
coelom
the space between the mesodermal layers that forms the body cavity of some animal phyla
coenzyme
an organic cofactor required for enzyme activity
colon
the large intestine
commensal
describes an organism that lives symbiotically with a host; this host neither benefits nor suffers from the association
conditioning
the association of physical, visceral response with an environmental stimulus with which it is not naturally associated; a learned response
cone
a cell in the retina that is sensitive to colors and is responsible for color vision
consumer
organism that consumes food from outside itself instead of producing it
contractile vacuole
a specialized structure that controls osmotic pressure by removing water from the cell
cornea
the outer, transparent layer of the eye
corpus callosum
a tract of nerve fibers connecting the two cerebral hemispheres
corpus luteum
a remnant of follicle after ovulation that secretes the hormone progesterone
cortex
in plants, the tissue between the epidermis and the vascular cylinder in the roots and stems of plants; in animals, the outer tissue of some organs
cortisone
a hormonal secretion of the adrenal cortex
cotyledon
a “seed leaf”; responsible for food digestion and storage in plant embryo
cretinism
a thyroid deficiency that results in stunted growth and feeblemindedness
crossing over
the exchange of parts of homologous chromosomes during meiosis
cross-pollination
the pollination of the pistil of one flower with pollen from the stamen of a different flower of the same species
Crustacea
a large class of arthropods, including crabs and lobsters
cuticle
a waxy protective layer secreted by the outer surface of plants, insects, etcetera
cytochrome
a hydrogen carrier containing iron that functions in many cellular processes, including respiration
cytokinesis
a process by which the cytoplasm and the organelles of the cell divide; the final stage of mitosis
cyton
the cell body of a neuron
cytoplasm
the living matter of a cell, located between the cell membrane and the nucleus
cytoskeleton
the organelle that provides mechanical support and carries out motility functions for the cell
cytosine
a nitrogen base that is present in nucleotides and nucleic acids; it is paired with guanine
deamination
the removal of an amino group from an organism, particularly from an amino acid
deletion
the loss of all or part of a chromosome
dendrite
the part of the neuron that transmits impulses to the cell body
deoxyribose
a five carbon sugar that has one oxygen atom less than ribose; a component of DNA
diastole
the passive, rhythmical expansion or dilation of the cavities of the heart (atria or ventricles) that allows these organs to fill with blood; preceded and followed by systole (contraction)
dicotyledon
a plant that has two seed leaves or cotyledons
diencephalon
the hind portion of the forebrain of vertebrates
differentation
a progressive change from which a permanently more mature or advanced state results
diffusion
the movement of particles from one place to another as a result of their random motion
digestion
the process of breaking down large organic molecules into smaller ones
dihybrid
an organism that is heterozygous for two different traits
dimorphism
the instance of polymorphism in which there is a difference of form between two members of a species, as between males and females
diploid
describes cells that have a double set of chromosomes in homologous pairs (2n)
disaccharide
a sugar composed of two combined monosaccharides
disjunction
the separation of homologous pairs of chromosomes following meiotic synapsis
DNA
deoxyribonucleic acid; found in cell nucleus, its basic unit is the nucleotide; contains coded genetic information; can replicate on the basis of heredity
dominance
a dominant allele suppresses the expression of the other member of an allele pair when both members are present
dorsal root
the sensory branch of each spinal nerve
duodenum
the most anterior portion of the small intestine of vertebrates, adjacent to the stomach; the continuation of the stomach into which the bile duct and pancreatic duct empty
ecological succession
the orderly process by which one biotic community replaces another until a climax community is established
ecology
the study of organisms in relation to their environment
ectoderm
the outermost embryonic germ layer that gives rise to the epidermis and the nervous system
egg
the female gamete; it is nonmotile, large in comparison to male gametes, and stores nutrients
electron transport chain
a complex carrier mechanism located on the inside of the inner mitochondrial membrane of the cell; releases energy and is used to form ATP
embolus
a blood clot that is formed within a blood vessel
emulsion
a colloidal system involving the dispersion of a liquid within a liquid
endemic
pertaining to a restricted locality; ecologically, occurring only in one particular region
endocrine gland
a ductless gland that secretes hormones directly into the bloodstream
endocytosis
a process by which the cell membrane is invaginated to form a vesicle which contains extracellular medium
endoderm
the innermost embryonic germ layer that gives rise to the lining of the alimentary canal and to the digestive and respiratory organs
endoplasmic reticulum
a network of membrane-enclosed spaces connected with the nuclear membrane; transports materials through the cell; can be soft or rough
enzyme
an organic catalyst and protein
endoplasm
the inner portion of the cytoplasm of a cell or the portion that surrounds the nucleus
endosperm
the triploid tissue in some seeds that contains stored food and is formed by the union of one sperm nucleus with two nuclei of the female’s gametophyte
epidermis
the outermost surface of an organism
epididymis
the coiled part of the sperm duct, adjacent to the testes in mammals
epiglottis
in mammals, a flap of tissue above the glottis; it folds back over the glottis in swallowing to close the air passages of the lungs; contains elastic cartilage
epicotyl
the portion of seed plant embryo above the cotyledon
epinephrine
adrenaline
epithelium
the cellular layer that covers external and internal surfaces
epiphyte
a plant that lives on another plant mensalistically
erythrocyte
an anucleate red blood cell that contains hemoglobin
esophagus
the portion of alimentary canal connecting the pharynx and the stomach
estrogen
a female sex hormone secreted by the follicle
ethanol fermentation
a form of anaerobic respiration found in yeast and bacteria
ethylene
a hormone that ripens fruit and induces aging
eukaryote
multicellular organism
Eustachian tube
an air duct from the middle ear to the throat that equalizes external and internal air pressure
excretion
the elimination of metabolic waster matter
exocrine
pertaining to a type of gland that releases its secretion through a duct
exocytosis
a process by which the vesicle in the cell fuses with the cell membrane and releases its contents to the outside
exoskeleton
describes arthropods and other animals whose skeletal or supporting structures are outside the skin
eye
a sensory organ capable of detecting light
F1
the first filial generation (first offspring)
F2
the second filial generation; offspring resulting from the crossing of individuals of the F1 generation
fallopian tube
the mammalian oviduct that leads from the ovaries to the uterus
feedback mechanism
the process by which a certain function is regulated by the amount of the substance it produces
femur
the thigh bone of vertebrates
fermentation
anaerobic respiration the yields 2 molecules of ATP, lactic acid, ethyl alcohol and carbon dioxide or some similar compound via the glycolytic pathway
fertilization
the fusion of sperm and the egg to produce a zygote
fibrin
protein threads that form in the blood during clotting
fibrinogen
blood protein that is transformed to fibrin upon clotting
fitness
the ability of an organism to contribute its alleles and therefore is phenotypic traits to future generations
flagellate
an organism that possesses one or more whiplike appendages called flagella
flagellum
a microscopic, whiplike filament that serves as a locomotor structure in flagellate cells
follicle
the sac in the ovary in which the egg develops
food vacuole
a vacuole in the cytoplasm in which digestion takes place (in protozoans)
frame shift mutation
a mutation involving the addition or loss of nucleotides
fruit
a mature ovary
FSH
an anterior pituitary hormone that stimulates the follicles in females and the function of the seminiferous tubules in males
functional groups
chemical groups attached to carbon skeletons that give compounds their functionality