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BIO SAT II Subject Test
N/A
511
Biology
12th Grade
07/06/2012

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Cards

Term
abiotic
Definition
nonliving, as in the physical environment\
Term
absorption
Definition
the process by which water and dissolved substances pass through a membrane\
Term
acetylcholine
Definition
a transmitter substance released from the axons of nerve cells at the synapse\
Term
active immunity
Definition
protective immunity to a disease in which the individual produces antibodies as a result of previous exposure to the antigen\
Term
adaptation
Definition
a behavioral or biological change that enables an organism to adjust to its environment\
Term
adaptive radiation
Definition
the production of a number of different species from a single ancestral species\
Term
adenosine phosphate
Definition
adenosine diphosphate (ADP) and adenosine triphosphate (ATP), which are energy storage molecules\
Term
ADH (vassopressin)
Definition
a hormone that regulates water reabsorption\
Term
adrenal cortex
Definition
the ourter part of the adrenal gland that secretes many hormones, including cortisone and aldosterone\
Term
adrenal medulla
Definition
the inner part of the adrenal gland that secretes adrenalin\
Term
adrenaline (epinephrin)
Definition
an "emergency" hormone stimulated by anger or fear; increase blood pressure and heart rate in order to supply the emergency needs of the muscles\
Term
adrenocorticotrophic hormone
Definition
usually referred to as ACTH and secreted by the anterior lobe of the pituitary gland; stimulates the adrenal cortex to produce its characteristic hormones\
Term
aerobe
Definition
an organism that requires oxygen for respiration and can live only in the presence of oxygen\
Term
aerobic
Definition
requiring free oxygen from the atmosphere for normal activity and respiration\
Term
aldosterone
Definition
hormone active in osmoregulation; a mineral corticoid produced by the adrenal cortex; stimulates reabsorption of Na+ and secretion of K+\
Term
alimentary canal
Definition
an organ centrally involved in the human digestive system\
Term
allantois
Definition
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\
Term
allele
Definition
one or two or more types of genes, each representing a particular trait; many alleles exist for a specific gene locus\
Term
alternation of generations
Definition
the description of a plant life cycle that consists of a diploid, asexual, sporophyte generation and a haploid, sexual, gametrophyte generation\
Term
alveolus
Definition
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\
Term
amnion
Definition
the extraembryonic membrane in birds, reptiles and mammals that surrounds the embryo, forming an amniotic sac\
Term
pseudopod
Definition
movement of amoeba\
Term
anaerobe
Definition
an organism that does not require free oxygen in order to respire\
Term
anaerobic
Definition
living or active in the absence of free oxygen; pertaining to respiration that is independent of oxygen\
Term
analogous
Definition
describes structures that have similar function but different evolutionary origins; e.g., a bird's wing and a moth's wing\
Term
anaphase
Definition
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)\
Term
androgen
Definition
a mall sex hormone (e.g., testosterone)\
Term
angiosperm
Definition
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\
Term
Annelida
Definition
the phylum to which segmented worms belong\
Term
anther
Definition
the part of the male reproductive organ (the stamen) that produces and stores pollen\
Term
antibiotic
Definition
an antipathogenic substance (e.g., penicillin)\
Term
antibody
Definition
globular proteins produced by tissues that destroy or inactivate antigens\
Term
antigen
Definition
a foreign protein that stimulates the production of antibodies when introduced into the body of an organism\
Term
aorta
Definition
the largest artery; carries blood from the left ventricle\
Term
aortic arch
Definition
blood vessels located between ascending and descending aortas that deliver blood to most of the upper body\
Term
appendage
Definition
a structure that extends from the trunk of an organism and is capable of active movements\
Term
aqueous humor
Definition
fluid in the eye, found between the cornea and the lens\
Term
Arachnida
Definition
a class of arthropods that includes scorpions, spiders, mites and ticks\
Term
artery
Definition
a blood vessel that carries blood away from the heart\
Term
Arthropoda
Definition
the phylum to which jointed-legged invertebrates belong, including insects, arachnids and crustaceans\
Term
asexual reproduction
Definition
the production of daughter cells by means other than the sexual union of gametes (as in budding and binary fission)\
Term
assimilation
Definition
the conversion of digested foods and other materials into forms usable by the body (i.e., the conversion of amino acids into proteins)\
Term
assortative mating
Definition
the type of mating that occurs when an organism selects a mating partner that resembles itself\
Term
atrium
Definition
the thin-walled anterior chamber of the heart (also called the auricle)\
Term
autolysis
Definition
self-digestion occurring in plant and animal tissues, particularly after they have ceased to function properly\
Term
autonomic nervous system
Definition
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\
Term
autosome
Definition
any chromosome that is not a sex chromosome\
Term
autotroph
Definition
an organism that utilizes the energy of inorganic materials such as water and carbon dioxide or the sun to manufacture organic materials\
Term
auxin
Definition
a plant growth hormone\
Term
axon
Definition
a nerve fiber\
Term
bacillus
Definition
bacteria that are rod shaped\
Term
bacteriophage
Definition
a type of virus that can destroy bacteria by infecting, parasitizing and eventually killing them\
Term
bile
Definition
an emulsifying agent secreted by the liver\
Term
bile salts
Definition
compounds in bile that aid in emulsification\
Term
binary fission
Definition
asexual reproduction; in this process, the parent organism splits into two equal daughter cells\
Term
binomial nomenclature
Definition
the system of naming an organism by its genus and species name\
Term
biome
Definition
a habitat zone, such as desert, grassland or tundra\
Term
biotic
Definition
living, as in living organisms in the environment\
Term
blastula
Definition
a stage of embryonic development in which the embryo consists of a hollow ball of cells\
Term
Bowman's capsule
Definition
part of the nephron in the kidney; involved in excretion\
Term
bud
Definition
in plants, an area of undifferentiated tissue covered by embryonic leaves\
Term
budding
Definition
a process of asexual reproduction in which the offspring develop from an outgrowth of the plant or animal\
Term
buffer
Definition
a substance that prevents appreciable changes in pH in solutions to which small quantities of acids or bases are added\
Term
calorie
Definition
a unit of heat; the amount of heat required to raise the temperature of one gram of water by one degree centigrade\
Term
Calvin cycle
Definition
cycle in photosynthesis that reduces fixed carbon to carbohydrates through the addition of electrons ("dark cycle")\
Term
cambium
Definition
undifferentiated tissue in the stem of a plant that aids growth in width\
Term
capillary
Definition
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\
Term
carapace
Definition
a bony or chitinous case or shield covering the back or part of the back of an animal (shell of a crab)\
Term
carbohydrate
Definition
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\
Term
carbon cycle
Definition
the recycling of carbon from decaying organisms for use in future generations\
Term
carnivore
Definition
a flesh-eating animal; a holotrophic animal that subsists on other animals or parts of animals\
Term
cation
Definition
an ion with a positive charge, or an ion that migrates towards the cathode (negative electrode) in an electric field\
Term
cell wall
Definition
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\
Term
cell wall plate
Definition
in mitosis of higher plants, the structure that forms between the divided nuclei of the two daughter cells and eventually becomes the cell wall\
Term
central nervous system
Definition
encompasses the brain and the spinal cord\
Term
centriole
Definition
the small granular body within the centrosome to which the spindle fibers attach\
Term
centromere
Definition
the place of attachment of the mitotic fiber to the chromosome\
Term
centrosome
Definition
a structure in animal cells containing centrioles from which the spindle fibers develop\
Term
cephalic
Definition
pertaining to the head\
Term
cerebellum
Definition
the hindbrain region that controls equilibrium and muscular coordination\
Term
cerebral cortex
Definition
the outer layer of cerebral hemispheres in the forebrain, consisting of gray matter\
Term
cerebral hemisphere
Definition
one of the paired lateral divisions of the forebrain\
Term
cerebrum
Definition
the largest portion of the human brain; it is believed to be the center of intelligence, conscious thought and sensation\
Term
chemosynthesis
Definition
the process by which carbohydrates are formed through chemical energy; found in bacteria\
Term
chemotropism
Definition
the orientation of cells or organisms in relation to chemical stimuli; the growth or movement response of organisms to chemical stimuli\
Term
chitin
Definition
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\
Term
chlorophyll
Definition
a green pigment that performs essential functions as an electron donor and light "entrapper" in photosynthesis\
Term
chloroplast
Definition
a plastid containing chlorophyll\
Term
Chordata
Definition
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\
Term
chorion
Definition
the outermost, extra-embryonic membrane of reptiles and birds\
Term
chromatid
Definition
one of the two strands that constitute a chromosome; chromatids are held together by the centromere\
Term
chromatin
Definition
a nuclear protein of chromosomes that stains readily\
Term
chromosome
Definition
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)\
Term
chyme
Definition
partially digested food in the stomach\
Term
circadian rhythms
Definition
daily cycles of behavior\
Term
cleavage
Definition
the division in animal cell cytoplasm caused by the pinching in of the cell membrane\
Term
climax community
Definition
the stable, biotic part of the ecosystem in which populations exist in balance with each other and with the environment\
Term
clotting
Definition
the coagulation of blood caused by the rupture of platelets and the interaction of fibrin, fibrinogen, thrombin, prothrombin and calcium ions\
Term
cloaca
Definition
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)\
Term
cochlea
Definition
the sensory organ of the inner ear of mammals; it is coiled and contains the organ of corti\
Term
codominant
Definition
the state in which two genetic traits are fully expressed and neither dominates\
Term
Coelentrata
Definition
an invertebrate animal phylum in which animals possess a single alimentary opening and tentacles with stinging cells\
Term
coelom
Definition
the space between the mesodermal layers that forms the body cavity of some animal phyla\
Term
coenzyme
Definition
an organic cofactor required for enzyme activity\
Term
colon
Definition
the large intestine\
Term
commensal
Definition
describes an organism that lives symbiotically with a host; this host neither benefits nor suffers from the association\
Term
conditioning
Definition
the association of physical, visceral response with an environmental stimulus with which it is not naturally associated; a learned response\
Term
cone
Definition
a cell in the retina that is sensitive to colors and is responsible for color vision\
Term
consumer
Definition
organism that consumes food from outside itself instead of producing it\
Term
contractile vacuole
Definition
a specialized structure that controls osmotic pressure by removing water from the cell\
Term
cornea
Definition
the outer, transparent layer of the eye\
Term
corpus callosum
Definition
a tract of nerve fibers connecting the two cerebral hemispheres\
Term
corpus luteum
Definition
a remnant of follicle after ovulation that secretes the hormone progesterone\
Term
cortex
Definition
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\
Term
cortisone
Definition
a hormonal secretion of the adrenal cortex\
Term
cotyledon
Definition
a "seed leaf"; responsible for food digestion and storage in plant embryo\
Term
cretinism
Definition
a thyroid deficiency that results in stunted growth and feeblemindedness\
Term
crossing over
Definition
the exchange of parts of homologous chromosomes during meiosis\
Term
cross-pollination
Definition
the pollination of the pistil of one flower with pollen from the stamen of a different flower of the same species\
Term
Crustacea
Definition
a large class of arthropods, including crabs and lobsters\
Term
cuticle
Definition
a waxy protective layer secreted by the outer surface of plants, insects, etcetera\
Term
cytochrome
Definition
a hydrogen carrier containing iron that functions in many cellular processes, including respiration\
Term
cytokinesis
Definition
a process by which the cytoplasm and the organelles of the cell divide; the final stage of mitosis\
Term
cyton
Definition
the cell body of a neuron\
Term
cytoplasm
Definition
the living matter of a cell, located between the cell membrane and the nucleus\
Term
cytoskeleton
Definition
the organelle that provides mechanical support and carries out motility functions for the cell\
Term
cytosine
Definition
a nitrogen base that is present in nucleotides and nucleic acids; it is paired with guanine\
Term
deamination
Definition
the removal of an amino group from an organism, particularly from an amino acid\
Term
deletion
Definition
the loss of all or part of a chromosome\
Term
dendrite
Definition
the part of the neuron that transmits impulses to the cell body\
Term
deoxyribose
Definition
a five carbon sugar that has one oxygen atom less than ribose; a component of DNA\
Term
diastole
Definition
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)\
Term
dicotyledon
Definition
a plant that has two seed leaves or cotyledons\
Term
diencephalon
Definition
the hind portion of the forebrain of vertebrates\
Term
differentation
Definition
a progressive change from which a permanently more mature or advanced state results\
Term
diffusion
Definition
the movement of particles from one place to another as a result of their random motion\
Term
digestion
Definition
the process of breaking down large organic molecules into smaller ones\
Term
dihybrid
Definition
an organism that is heterozygous for two different traits\
Term
dimorphism
Definition
the instance of polymorphism in which there is a difference of form between two members of a species, as between males and females\
Term
diploid
Definition
describes cells that have a double set of chromosomes in homologous pairs (2n)\
Term
disaccharide
Definition
a sugar composed of two combined monosaccharides\
Term
disjunction
Definition
the separation of homologous pairs of chromosomes following meiotic synapsis\
Term
DNA
Definition
deoxyribonucleic acid; found in cell nucleus, its basic unit is the nucleotide; contains coded genetic information; can replicate on the basis of heredity\
Term
dominance
Definition
a dominant allele suppresses the expression of the other member of an allele pair when both members are present\
Term
dorsal root
Definition
the sensory branch of each spinal nerve\
Term
duodenum
Definition
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\
Term
ecological succession
Definition
the orderly process by which one biotic community replaces another until a climax community is established\
Term
ecology
Definition
the study of organisms in relation to their environment\
Term
ectoderm
Definition
the outermost embryonic germ layer that gives rise to the epidermis and the nervous system\
Term
egg
Definition
the female gamete; it is nonmotile, large in comparison to male gametes, and stores nutrients\
Term
electron transport chain
Definition
a complex carrier mechanism located on the inside of the inner mitochondrial membrane of the cell; releases energy and is used to form ATP\
Term
embolus
Definition
a blood clot that is formed within a blood vessel\
Term
emulsion
Definition
a colloidal system involving the dispersion of a liquid within a liquid\
Term
endemic
Definition
pertaining to a restricted locality; ecologically, occurring only in one particular region\
Term
endocrine gland
Definition
a ductless gland that secretes hormones directly into the bloodstream\
Term
endocytosis
Definition
a process by which the cell membrane is invaginated to form a vesicle which contains extracellular medium\
Term
endoderm
Definition
the innermost embryonic germ layer that gives rise to the lining of the alimentary canal and to the digestive and respiratory organs\
Term
endoplasmic reticulum
Definition
a network of membrane-enclosed spaces connected with the nuclear membrane; transports materials through the cell; can be soft or rough\
Term
enzyme
Definition
an organic catalyst and protein\
Term
endoplasm
Definition
the inner portion of the cytoplasm of a cell or the portion that surrounds the nucleus\
Term
endosperm
Definition
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\
Term
epidermis
Definition
the outermost surface of an organism\
Term
epididymis
Definition
the coiled part of the sperm duct, adjacent to the testes in mammals\
Term
epiglottis
Definition
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\
Term
epicotyl
Definition
the portion of seed plant embryo above the cotyledon\
Term
epinephrine
Definition
adrenaline\
Term
epithelium
Definition
the cellular layer that covers external and internal surfaces\
Term
epiphyte
Definition
a plant that lives on another plant mensalistically\
Term
erythrocyte
Definition
an anucleate red blood cell that contains hemoglobin\
Term
esophagus
Definition
the portion of alimentary canal connecting the pharynx and the stomach\
Term
estrogen
Definition
a female sex hormone secreted by the follicle\
Term
ethanol fermentation
Definition
a form of anaerobic respiration found in yeast and bacteria\
Term
ethylene
Definition
a hormone that ripens fruit and induces aging\
Term
eukaryote
Definition
multicellular organism\
Term
Eustachian tube
Definition
an air duct from the middle ear to the throat that equalizes external and internal air pressure\
Term
excretion
Definition
the elimination of metabolic waster matter\
Term
exocrine
Definition
pertaining to a type of gland that releases its secretion through a duct\
Term
exocytosis
Definition
a process by which the vesicle in the cell fuses with the cell membrane and releases its contents to the outside\
Term
exoskeleton
Definition
describes arthropods and other animals whose skeletal or supporting structures are outside the skin\
Term
eye
Definition
a sensory organ capable of detecting light\
Term
F1
Definition
the first filial generation (first offspring)\
Term
F2
Definition
the second filial generation; offspring resulting from the crossing of individuals of the F1 generation\
Term
fallopian tube
Definition
the mammalian oviduct that leads from the ovaries to the uterus\
Term
feedback mechanism
Definition
the process by which a certain function is regulated by the amount of the substance it produces\
Term
femur
Definition
the thigh bone of vertebrates\
Term
fermentation
Definition
anaerobic respiration the yields 2 molecules of ATP, lactic acid, ethyl alcohol and carbon dioxide or some similar compound via the glycolytic pathway\
Term
fertilization
Definition
the fusion of sperm and the egg to produce a zygote\
Term
fibrin
Definition
protein threads that form in the blood during clotting\
Term
fibrinogen
Definition
blood protein that is transformed to fibrin upon clotting\
Term
fitness
Definition
the ability of an organism to contribute its alleles and therefore is phenotypic traits to future generations\
Term
flagellate
Definition
an organism that possesses one or more whiplike appendages called flagella\
Term
flagellum
Definition
a microscopic, whiplike filament that serves as a locomotor structure in flagellate cells\
Term
follicle
Definition
the sac in the ovary in which the egg develops\
Term
food vacuole
Definition
a vacuole in the cytoplasm in which digestion takes place (in protozoans)\
Term
frame shift mutation
Definition
a mutation involving the addition or loss of nucleotides\
Term
fruit
Definition
a mature ovary\
Term
FSH
Definition
an anterior pituitary hormone that stimulates the follicles in females and the function of the seminiferous tubules in males\
Term
functional groups
Definition
chemical groups attached to carbon skeletons that give compounds their functionality\
Term
gall bladder
Definition
an organ that stores bile\
Term
gamete
Definition
a sex or reproductive cell that must fuse with another of the opposite type to form a zygote\
Term
gametophyte
Definition
the haploid, sexual stage in the life cycle of plants\
Term
ganglion
Definition
a grouping of neuron cell bodies that acts as a coordinating center\
Term
gastrula
Definition
a stage of embryonic development characterized by the differentiation of the cells into the ectoderm and endoderm germ layers and by the formation of the archenteron\
Term
gene
Definition
the portion of a DNA molecule that serves as a unit of heredity; found on the chromosome\
Term
gene frequency
Definition
a decimal fraction that represents the presence of an allele for all members of a population that have a particular gene locus\
Term
genetic code
Definition
a four-letter code made up of the DNA nitrogen bases A, T, G and C; each chromosome is made up of thousands of these bases\
Term
genetic drift
Definition
random evolutionary changes in the genetic makeup of a population\
Term
genotype
Definition
the genetic makeup of an organism without regard to physical appearance\
Term
genus
Definition
in taxonomy, a classification between species and family\
Term
geographical barrier
Definition
any physical feature that prevents the ecological niches of different organisms from overlapping\
Term
geotropism
Definition
any movement or growth of a living organism in response to the force of gravity\
Term
germ cell
Definition
a reproductive cell\
Term
germ layer
Definition
one of the primary tissues of the embryo\
Term
gibberellin
Definition
a hormone that stimulates plant stem elongation\
Term
gill slit
Definition
a perforation leading from the pharynx to the outside environment that is a characteristic of chordates at one stage of their development\
Term
glomerulus
Definition
a network of capillaries in the Bowman's capsules of the kidney\
Term
glottis
Definition
in mammals, the slitlike opening formed by the vocal folds in the larynx\
Term
glycogen
Definition
a starch form in animals; glucose is converted to this in the liver\
Term
gylcolysis
Definition
the anaerobic respiration of carbohydrates\
Term
goiter
Definition
an enlargement of the thyroid gland due to lack of iodine\
Term
Golgi apparatus
Definition
membranous organelles involved in the storage and modification of secretory products\
Term
gonads
Definition
the reproductive organ that produces sex cells\
Term
Graffian follicle
Definition
the cavity in the mammalian ovary in which the egg ripens\
Term
granum
Definition
the smallest particle that is capable of carrying out photosynthesis; the functional unit of a chloroplast\
Term
gray matter
Definition
a portion of the CNS consisting of cytons (cell bodies), their dendrites and synaptic connections\
Term
guanine
Definition
a purine (nitrogenous base) component of nucleotides and nucleic acids; links with cytosine in DNA\
Term
guard cell
Definition
one of a pair of kidney-shaped cells that surround a stomate and regulate the size of the stomate in a leaf\
Term
gymnosperm
Definition
a plant that belongs to the class of seed plants in which the seeds are not enclosed in an ovary; includes the conifers\
Term
haploid
Definition
describes cells (gametes) that have half the chromosome number typical of the species\
Term
hemoglobin
Definition
a protein compound containing iron that is found in red blood cells\
Term
hepatic portal system
Definition
the veins that carry blood from the digestive organs to the liver\
Term
herbivore
Definition
a plant-eating animal\
Term
hermaphrodite
Definition
an organism that possesses both the male and the female reproductive organs\
Term
heterotroph
Definition
an organism that must get its inorganic and organic raw materials from the environment; a consumer\
Term
heterozygous
Definition
describes an individual that possesses two contrasting alleles for a given trait\
Term
homeotherm
Definition
an animal with a constant body temperature\
Term
homologous
Definition
describes two or more structures that have similar forms, positions and origins despite the differences between their current functions\
Term
homozygous
Definition
describes an individual that has the same gene for the same trait on each homologous chromosome\
Term
hormone
Definition
a chemical messenger that is secreted by one part of the body and carried by the blood to affect another part of the body, usually a muscle or gland\
Term
host
Definition
any organism that is the victim of a parasite\
Term
humerus
Definition
a bone of the upper arm\
Term
hybrid
Definition
an offspring that is heterozygous for one or more gene pairs\
Term
hydrostatic skeleton
Definition
fluid skeleton of annelids\
Term
hyperthyroidism
Definition
an over secretion of thyroid that leads to high metabolism and exopthalmia goiter\
Term
hypertonic
Definition
describes a fluid that has a higher osmotic pressure than another fluid it is compared to\
Term
hypocoytl
Definition
the portion of the embryonic seed plant below the point of attachment of the coytledon; form the root\
Term
hypothalamus
Definition
a section of the posterior forebrain associated with the pituitary gland\
Term
hypotonic
Definition
describes a fluid that has a lower osmotic pressure than a fluid it is compared to\
Term
ilium
Definition
the dorsal part of the hip girdle\
Term
immunity
Definition
a resistance to disease developed through the immune system\
Term
imprinting
Definition
the process by which environmental patterns or objects presented to a developing organism during a "critical period" of its growth is accepted as a permanent element of its behavior\
Term
incomplete dominance
Definition
genetic blending; each allele exerts some influence on the phenotype\
Term
independent assortment
Definition
the law by which genes on different chromosomes are inherited independently of each other\
Term
ingestion
Definition
the intake of food from the environment into the alimentary canal\
Term
inner ear
Definition
a fluid-filled sensory apparatus that aids balance and hearing\
Term
insulin
Definition
a hormone produced by the Islets of Langerhans in the pancreas\
Term
integument
Definition
refers to protective covering\
Term
interphase
Definition
a metabolic stage between mitoses in which genetic material is reproduced\
Term
interstitial cells
Definition
cells which in the female are located between the ovarian follicles and in the male are located between the seminiferous tubules of the testes\
Term
inversion
Definition
occurs when a segment of genetic material on a chromosome becomes reversed\
Term
iris
Definition
the colored part of the eye that is capable of contracting and regulating the size of the pupils\
Term
irritability
Definition
the ability to respond to a stimulus\
Term
isolation
Definition
the separation of some members of a population from the rest of their species; prevents interbreeding and may lead to the development of a new species\
Term
isomer
Definition
one of a group of compounds that is identical in a atomic composition, but different in structure and arrangement\
Term
isotonic
Definition
describes a fluid that has the same osmotic pressure as a fluid it is compared to\
Term
Krebs cycle
Definition
process of aerobic respiration that fully harvests the energy of glucose; also known as the citric acid cycle\
Term
lactase
Definition
the enzyme that acts upon lactose\
Term
lacteal
Definition
a lymph tubule located in the villus that absorbs fatty acids\
Term
lactid acid fermentation
Definition
a type of anaerobic respiration found in fungi, bacteria and human muscle cells\
Term
larva
Definition
a period in the development of animals between the embryo and adult stages; starts at hatching and ends in metamorphasis\
Term
legume
Definition
a flowering plant with simple dry fruit, characterized by nodes on their roots that contain nitrogen-fixing bacteria\
Term
lens
Definition
a structure of the eye that focuses images on the retina by changing its convexity\
Term
levels of structure
Definition
different relationships that are formed in proteins between the original sequence of amino acids and more complex three-dimensional compounds\
Term
lichen
Definition
an association between an algae and a fungus that is symbiotic and mutualistic in nature\
Term
linkage
Definition
occurs when different traits are inherited together more often than they would have been by chance along; it is assumed that these traits are linked on the same chromosome\
Term
lipase
Definition
a fat-digesting hormone\
Term
lipid
Definition
a fat or oil\
Term
littoral zone
Definition
a marine biome; a region on the continental shelf that contains an ocean area with depths of up to 600 ft\
Term
Loop of Henle
Definition
the thin, bent part of the renal tubule that is the site of the counter-current flow and the sodium gradient\
Term
luteinizing hormone (LH)
Definition
secreted by the anterior pituitary gland, this hormone stimulates the conversion of a follicle into the corpus luteum and the secretion of progesterone by the corpus luteum\
Term
lymph
Definition
a body fluid that flows in its own circulatory fluid in lymphatic vessels separate from blood circulation\
Term
lymph capillary
Definition
one of many tubules that absorb tissue fluid and return it to the bloodstream via the lymphatic system\
Term
lymphocyte
Definition
a kind of white blood cell in vertebrates that is characterized by a rounded nucleus; involved in the immune response\
Term
lysosome
Definition
an organelle that contains enzymes that aid in intracellular digestion\
Term
macula
Definition
a sensory hair structure in the utriculus and the sacculus of the inner ear; orients the head with respect to gravity\
Term
malleus
Definition
the outermost bone of the middle ear (hammer)\
Term
malpighian tubules
Definition
tubules that excrete metabolic wastes into the hindgut in arthropods\
Term
maltase
Definition
an enzyme that acts upon maltose and converts it into glucose\
Term
maltose
Definition
a 12-carbon sugar that is formed by the union of two glucose units (a disaccharide)\
Term
marsupial
Definition
a pouched mammal, such as the kangaroo or opossum\
Term
medulla
Definition
the inner layer of an organ surrounded by the cortex\
Term
medulla oblongata
Definition
the posterior part of the brain that controls the rate of breathing and other autonomic functions\
Term
medusa
Definition
a jellyfish\
Term
meiosis
Definition
a process of cell division whereby each daughter cell receives only one set of chromosomes; the formation of gametes\
Term
Mendelian laws
Definition
laws of classical genetics established through Mendel's experiments with peas\
Term
meninges
Definition
three membranes that envelop the brain and spinal cord (pia mater, dura mater and arachnoid)\
Term
meristem
Definition
an undifferentiated, growing region of a plant that is constantly undergoing cell division and differentiation\
Term
mesoderm
Definition
the primary germ layer, developed from the lip of the blastopore, that gives rise to the skeleton, the circulatory system and many organs and tissues between the epidermis and the epithelium\
Term
metabolism
Definition
a group of life-maintaining processes that includes nutrition, respiration (the production of usable energy) and the synthesis and degradation of biochemical substances\
Term
metamorphosis
Definition
the transformation of an immature animal into an adult; a change in the form of an organ or structure\
Term
metaphase
Definition
a stage of mitosis; chromosomes line up at the equator of the cell\
Term
microbodies
Definition
organelles that serve as specialized containers for metabolic reactions\
Term
micron (micrometer)
Definition
one-thousandth of a millimeter; a unit of microscopic length\
Term
mitochondria
Definition
cytoplasmic organelles that serve as sites of respiration; a rod-shaped body in the cytoplasm known to be the center of cellular respiration\
Term
mitosis
Definition
a type of nuclear division that is characterized by complex chromosomal movement and the exact duplication of chromosomes; occurs in somatic cells\
Term
monocotyledon
Definition
a plant that has a single cotyledon or seed-leaf\
Term
monohybrid
Definition
an individual that is heterozygous for only one trait\
Term
monosaccharide
Definition
a simple sugar\
Term
morphology
Definition
the study of form and structure\
Term
morula
Definition
the solid ball of cells the results from cleavage of an egg; a solid blastula that precedes the blastula stage\
Term
mucosa
Definition
a mucus-secreting membrane\
Term
mutagenic agent
Definition
agent that induces mutations; typically carcinogenic\
Term
mutation
Definition
changes in genes that are inherited\
Term
mutualism
Definition
a symbiotic relationship from which both organisms involved derive some benefit\
Term
myelin sheath
Definition
a fatty sheath surrounding the axon of a neuron that aids in stimulus transmission; it is secreted by the Schwann cells\
Term
NAD
Definition
an abbreviation of nicotinamide-adenine-dinucleotide, also called DPN; a respiratory oxidation-reduction molecule\
Term
NADP
Definition
an abbreviation of nicotinamide-adenine-dinucleotide-phosphate, also called TPN; an organic compound that serves as an oxidation-reduction molecule\
Term
nephron
Definition
functional urinary tubules responsible for excretion in the kidney of vertebrates\
Term
nerve
Definition
a bundle of nerve axons\
Term
nerve cord
Definition
a compact linear organization of nerve tissues with ganglia in the CNS\
Term
nerve net
Definition
a multidirectional sensory system of lower animals such as the hydra, consisting of nerve fibers spread throughout the ectoderm\
Term
neural tube
Definition
an embryonic structure that gives rise to the central nervous system\
Term
neuron
Definition
a nerve cell\
Term
niche
Definition
the functional role and position of an organism in an ecosystem; embodies every aspect of the organism's existence\
Term
nictitating membrane
Definition
a thin, transparent, eyelid-like membrane that opens and closes laterally across the cornea of many vertebrates (the third eyelid)\
Term
nitrogen cycle
Definition
the recycling of nitrogen from decaying organism for use in future generations\
Term
nondisjunction
Definition
the failure of some homologous pairs of chromosomes to separate following meiotic synapsis\
Term
notochord
Definition
a flexible, supportive rod running longitudinally through the dorsum ventral to the nerve cord; found in lower chordates and in the embryos of vertebrates\
Term
nuclear membrane
Definition
a membrane that envelopes the nucleus and separates it from the cytoplasm; present in eukaryotes\
Term
nucleolus
Definition
a dark-staining small body within the nucleus; composed of RNA\
Term
nucleotide
Definition
an organic molecule consisting of joined phosphate, 5-carbon sugar (deoxyribose or ribose), and a purine or a pyrimidine (adenine, guanine, uracil, thymine or cytosine)\
Term
nucleus
Definition
an organelle that regulates cell functions and contains the genetic material of the cell\
Term
olfactory
Definition
related to the sense of smell\
Term
oogenesis
Definition
a process of formation of ova\
Term
organelle
Definition
a specialized structure that carries out particular functions for eukaryotic cells\
Term
osmoregulation
Definition
the ways in which organisms regulate their supply of water\
Term
osmosis
Definition
the diffusion of water through a semipermeable membrane, from an area of greater concentration to an area of lesser concentration\
Term
ovary
Definition
the female gonad in animals; the base of the pistil in plants\
Term
oviduct
Definition
a tube connecting the ovaries and the uterus\
Term
oxidation
Definition
the removal of hydrogen or electrons from a compound or addition of oxygen; half of a redox (oxidation or reduction) process\
Term
pairing
Definition
an association of homologous chromosomes during the first meiotic division\
Term
parasitism
Definition
a relationship in which one organism benefits at the expense of another\
Term
parasympathetic
Definition
pertaining to a subdivision of the autonomic nervous system of vertebrates\
Term
parathyroid
Definition
an endocrine gland of vertebrates, usually paired, and located near or within the thyroid that secretes parathormone, which controls the metabolism of calcium\
Term
parenchyma
Definition
plant tissue consisting of large thin-walled cells for storage\
Term
passive immunity
Definition
a resistance to disease produced through the injection of antibodies\
Term
parthenogenesis
Definition
a form of asexual reproduction in which the egg develops in the absence of sperm\
Term
pathogen
Definition
a disease-causing organism\
Term
pedigree
Definition
a family tree depicting the inheritance of a particular genetic trait over several generations\
Term
pelagic zone
Definition
a marine biome typical of the open seas\
Term
pepsin
Definition
a stomach enzyme that partially digests proteins\
Term
peptide
Definition
the kind of bond formed when two amino acid units are jointed end to end\
Term
peripheral nervous system
Definition
comprises somatic and autonomic nervous systems; consists of cranial nerves and spinal nerves\
Term
peristalsis
Definition
waves of contraction and relaxation passing along a tubular structure, such as the digestive tube\
Term
permeability
Definition
degree of penetrability, as in membranes that allow given substances to pass through; the ability to penetrate\
Term
pH
Definition
a symbol that denotes the relative concentration of hydrogen ions in a solution\
Term
phagocyte
Definition
any cell capable of ingesting another cell\
Term
pharynx
Definition
the part of the alimentary canal between the mouth and the esophagus\
Term
phenotype
Definition
the physical appearance or makeup of an individual, as opposed to its genetic makeup\
Term
pheromone
Definition
substance secreted by organisms that influences the behavior of other members of the same species\
Term
phloem
Definition
the vascular tissue of a plant that transports organic materials (photosynthetic products) from the leaves to other parts of the plant\
Term
photolysis
Definition
a process of photosynthesis in which water is split into H+ and OH-; the hydrogen ion is then joined to NADP\
Term
photoperiodism
Definition
a response by an organism to the duration and timing of light and dark conditions\
Term
phototropism
Definition
plant growth stimulated by light (stem: +, towards light; root: -, away from light)\
Term
phylogeny
Definition
the study of the evolutionary descent and interrelations of groups of organisms\
Term
phylum
Definition
a category of taxonomic classification that is ranked above class and under kingdoms\
Term
physiology
Definition
the study of all living processes, activities and functions\
Term
pineal body
Definition
a structure found between the cerebral hemispheres of vertebrates; secretes melatonin\
Term
pinocytosis
Definition
the intake of fluid droplets into a cell\
Term
pistil
Definition
the part of the flower that bears the female gametophyte\
Term
pith
Definition
the central tissue of a stem, used for food storage\
Term
pituitary
Definition
a gland composed of two parts, anterior and posterior, each with its own secretions; called the "master gland" because its hormones stimulate secretions by other glands\
Term
placenta
Definition
a structure formed by the wall of the uterus and the chorion of the embryo; serves as the area in which the embryo obtains nutrition from the parent\
Term
planaria
Definition
the class of free-living flatworms\
Term
plankton
Definition
passively floating or drifting flora and fauna of a body of water; consists mainly of microscopic organisms\
Term
plasma
Definition
the liquid part of blood\
Term
plasma membrane
Definition
the cell membrane\
Term
plasmodium
Definition
a motile, multinucleate mass of protoplasm resulting from fusion of uninuclear amoeboid cells\
Term
plastid
Definition
cytoplasmic bodies within a plant cell that are often pigmented\
Term
platelet
Definition
small, disc-shaped bodies in the blood that play a chief role in coagulation\
Term
pleural cavity
Definition
the cavity between the lungs and the wall of the chest\
Term
plexus
Definition
a network, particularly of nerve or blood vessels\
Term
point mutation
Definition
a mutation in which a single nucleotide base is substituted for another nucleotide base, or an extra nucleotide base is added\
Term
polar body
Definition
nonfunctional haploid cells created during meiosis in females; they have very little cytoplasm-most has gone into the functional egg cell\
Term
pollen
Definition
the microspore of a seed plant\
Term
pollination
Definition
the transfer of pollen to the micropyle or to a receptive surface that is associated with an ovule (such as stigma)\
Term
polymer
Definition
a large molecule that is composed of many similar molecule units\
Term
polymorphism
Definition
the individual differences of form among the members of a species\
Term
polyp
Definition
a typical coelenterate individual with a hollow tubular body whose outer ectoderm is separated from its inner ectoderm by mesoglea\
Term
polyploidy
Definition
a condition in which an organism may have a multiple of the normal number of chromosomes (4n, 6n, etc)\
Term
polysaccharide
Definition
a carbohydrate that is composed of many monosaccharide units joined together\
Term
pons
Definition
the part of the hindbrain located in the brain stem\
Term
population
Definition
all the members of a given species inhabiting a certain locale\
Term
Porifera
Definition
the phylum of sponges\
Term
primary oocyte
Definition
a cell that divides to form the polar body and the secondary oocyte\
Term
primary spermatocyte
Definition
a cell that divides to form two secondary spermatocytes\
Term
producer
Definition
organism that produces its own food; first stage in the food chain\
Term
progesterone
Definition
the hormone secreted by the corpus luteum of vertebrates and the placenta of mammals; its function is to maintain the endometrium\
Term
prokaryote
Definition
unicellular organism with simple cell structure\
Term
prophase
Definition
a mitotic or meiotic stage in which the chromosomes become visible and during which the spindle fibers form; synapsis takes place during the first meiotic prophase\
Term
protein
Definition
one of a class of organic compounds that is composed of many amino acids; contains C, H, O and N\
Term
prothrombin
Definition
a constituent of the plasma of the blood of vertebrates; it is converted to thrombin by thrombokinase in the presence of calcium ions, thus contributing to the clotting of blood\
Term
Protista
Definition
a kingdom of unicellular living organisms that are neither animals nor plants; includes some groups of algae, slime molds and protozoa\
Term
ptyalin
Definition
a digestive enzyme of the saliva that turns starch into maltose (salivary amylase)\
Term
pulmonary
Definition
relating to the lung\
Term
pupil
Definition
an opening in the eye whose size is regulated by the iris\
Term
purine
Definition
a nitrogenous base such as adenine or guanine; when joined with sugar or phosphate, a component of nucleotides and nucleic acids\
Term
pyrimidine
Definition
a nitrogen base such as cytosine, thymine and uracil; when joined with sugar or phosphate, a component of nucleotides and nucleic acids\
Term
pyloric valve
Definition
a muscular valve regulating the flow of food from the stomach to the small intestine\
Term
recessive
Definition
pertains to a gene or characteristic that is masked when a dominant allele is present\
Term
recombinant DNA technology
Definition
technology that allows for manipulation of genetic material\
Term
reduction
Definition
a change from a diploid nucleus to a haploid nucleus, as in meiosis\
Term
regeneration
Definition
the ability of certain animals to regrow missing body parts\
Term
respiration
Definition
a chemical action that releases energy from glucose to form ATP\
Term
respiratory center
Definition
the area of medulla that regulates the rate of breathing\
Term
reticulum
Definition
a network or mesh of fibrils, fibers or filaments\
Term
retina
Definition
the innermost tissue layer of the eyeball that contains light-sensitive receptor cells\
Term
Rh factor
Definition
an antigen in blood; can cause erythroblastosis fetalis when the mother is Rh- and the fetus is Rh+\
Term
rhizome
Definition
an underground stem\
Term
ribosome
Definition
an organelle in the cytoplasm that contains RNA; serves as the site of protein synthesis\
Term
rhodopsin
Definition
the pigment in rod cells that causes light sensitivity\
Term
rickettsia
Definition
a kind of microorganism that is between a virus and a bacterium; parasitic within the cells of insects and ticks\
Term
RNA
Definition
an abbreviation of ribonucleic acid, a nucleic acid in which the sugar is ribose; a product of DNA transcription that serves to control certain cell activities\
Term
rod
Definition
a cell in the retina that is sensitive to weak light\
Term
root hair
Definition
outgrowths of a root's epidermal cells that allow for greater surface area for absorption of nutrients and water\
Term
saprophyte
Definition
an organism that obtains its nutrients from dead organisms\
Term
secondary tissue
Definition
tissue formed by the differentiation of cambium that causes a growth in width of a plant system\
Term
selective breeding
Definition
the creation of certain strains of specific traits through control of breeding\
Term
self-pollination
Definition
the transfer of pollen from the stamen to the pistil of the same flower\
Term
semicircular canals
Definition
fluid-filled structures in the inner ear that are associated with the sense of balance\
Term
seminal fluid
Definition
semen\
Term
seminiferous tubules
Definition
structures in the testes that produce sperm and semen\
Term
sensory neuron
Definition
a neuron that picks up impulses from receptors and transmits them to the spinal cord\
Term
serum
Definition
the fluid that remains after fibrinogen is removed from the blood plasma of vertebrates\
Term
sex chromosome
Definition
there are two kinds of sex chromosomes, X and Y; XX signifies a female and XY signifies a male\
Term
sex linkage
Definition
occurs when certain traits are determined by genes on sex chromosomes\
Term
sinus
Definition
a space in the body\
Term
small intestine
Definition
the site of most digestion of nutrients and absorption of digested nutrients\
Term
smooth muscle
Definition
involuntary muscle\
Term
somatic cell
Definition
any cell that is not a reproductive cell\
Term
species
Definition
a group of populations that can interbreed\
Term
spermatogenesis
Definition
the process of forming the sperm cells from primary spermatocytes\
Term
spindle
Definition
a structure that arises during mitosis and helps separate the chromosomes; composed of tubulin\
Term
spiracle
Definition
the external opening of the trachea in insects\
Term
sphincter
Definition
a ring-shaped muscle that is capable of closing a tubular opening by constriction\
Term
spore
Definition
a reproductive cell that is capable of developing directly into an adult\
Term
sporophyte
Definition
an organism that produces spores; a phase in the diploid-haploid life cycle that alternates with a gametophyte phase\
Term
stamen
Definition
the part of the flower that produces pollen\
Term
steroid
Definition
one of a class of organic compounds that contains a molecular skeleton of four fused rings of carbon\
Term
stigma
Definition
the uppermost portion of pistil upon which pollen grains alight\
Term
stoma
Definition
a microscopic opening located in the epidermis of a leaf and formed by a pair of guard cells\
Term
stomach
Definition
the portion of alimentary canal in which some protein digestion occurs\
Term
stroma
Definition
a dense fluid within the chloroplast in which CO2 is converted into sugars in photosynthesis\
Term
style
Definition
a stalklike or elongated body part, usually pointed at one end\
Term
substrate
Definition
a substance that is acted upon by an enzyme\
Term
sucrase
Definition
an enzyme that acts upon sucrose\
Term
symbiosis
Definition
the living together of two organisms in an intimate relationship\
Term
sympathetic
Definition
pertaining to a subdivision of the autonomic nervous system\
Term
synapse
Definition
the junction or gap between the axon terminal of one neuron and the dendrites of another neuron\
Term
synergistic
Definition
describes organisms that are cooperative in action, such as hormones or other growth factors that reinforce each other's activity\
Term
synaptic terminal
Definition
the swelling at the end of an axon\
Term
synapsis
Definition
the pairing of homologous chromosomes during meiosis\
Term
systole
Definition
the contraction of the atria or ventricles of the heart\
Term
taiga
Definition
a terrestrial habitat zone that is characterized by large tracts of coniferous forests, long and cold winters, and short summers\
Term
taxonomy
Definition
the science of classification of living things\
Term
telophase
Definition
a mitotic stage in which nuclei reform and nuclear membrane reappears\
Term
test cross
Definition
the breeding of an organism with a homozygous recessive in order to determine whether an organism is homozygous dominant or heterozygous dominant for a given trait\
Term
testes
Definition
the male gonads that produce sperm and male hormones\
Term
tetrad
Definition
a pair of chromosome pairs present during the first metaphase of meiosis\
Term
thalamus
Definition
a lateral region of the forebrain\
Term
thermoregulation
Definition
the ways in which organisms regulate their internal heat\
Term
thoracic duct
Definition
a major lymphatic that empties lymph into a vein in the neck\
Term
thorax
Definition
the part of the body of an animal that is between the neck or head and the abdomen\
Term
thrombin
Definition
a substance that participates in the clotting of blood in vertebrates\
Term
thrombokinase
Definition
the enzyme released from the blood platelets in vertebrates during clotting\
Term
thymine
Definition
a pyrimidine component of nucleic acids and nucleotides; pairs with adenine in DNA\
Term
thymus
Definition
a ductless gland in upper chest region concerned with immunity and the maturation of lymphocytes\
Term
thyroid
Definition
an endocrine gland located in the neck that produces thyroxin\
Term
thryoxin
Definition
a hormone of the thyroid that regulates basal metabolism\
Term
tissue
Definition
a mass of cells that have similar structures and perform similar functions\
Term
trachea
Definition
an air-conducting tube\
Term
transcription
Definition
the fist stage of protein synthesis, in which the information coded in the DNA base is transcribed onto a strand of mRNA\
Term
translation
Definition
the final stages of protein synthesis in which the genetic code of nucleotide sequences is translated into a sequences of amino acids\
Term
translocation
Definition
the transfer of a piece of chromosome to another chromosome\
Term
transpiration
Definition
the evaporation of water from leaves or other exposed surfaces of plants\
Term
trilobite
Definition
a marine arthropod, now extinct, that lived during the Paleozoic era\
Term
trypsin
Definition
an enzyme from the pancreas that digests proteins in the small intestine\
Term
tundra
Definition
the biome located between the polar region and the tiaga\
Term
turgor pressure
Definition
the pressure exerted by the contents of a cell against the cell membrane or cell wall\
Term
umbilicus
Definition
the navel\
Term
ungulate
Definition
a hoofed animal\
Term
uracil
Definition
a pyrimidine found in RNA (but not DNA); pairs with DNA adenine\
Term
urea
Definition
an excretory product of protein metabolism\
Term
ureter
Definition
a duct that carries urine from the kidneys to the bladder\
Term
urethra
Definition
a duct through which the urine passes from the bladder to the outside\
Term
urinary bladder
Definition
an organ that stores urine temporarily before it is excreted\
Term
urine
Definition
fluid excreted by the kidney containing urea, water, salts, etc\
Term
uterus
Definition
the womb in which the fetus develops\
Term
vacuole
Definition
a space in the cytoplasm of a cell that contains fluid\
Term
vagus nerve
Definition
the tenth cranial nerve that innervates digestive organs, heart and other areas\
Term
vein
Definition
a blood vessel that carries blood back to the heart from the capillaries\
Term
ventral root
Definition
the basal branch of each spinal nerve; carries motor neurons\
Term
ventricle
Definition
the more muscular chamber(s) of the heart that pump blood to the lungs and to the rest of the body\
Term
vestigial organ
Definition
an organ that is not functional in an organism, but was functional at some period in its evolution\
Term
villus
Definition
a small projection in the walls of the small intestine that increases the surface area available for absorption\
Term
vitamin
Definition
an organic nutrient required by organisms in small amounts to aid in proper metabolic processes\
Term
white matter
Definition
an accumulation of axons within the CNS that is white because it is fatty, myelin sheath\
Term
wood
Definition
xylem that is no longer being used\
Term
xylem
Definition
vascular tissue of the plant that aids in support and carries water\
Term
yolk sac
Definition
a specialized structure that leads to the digestive tract of a developing organism and provides it with food during early development\
Term
zygote
Definition
a cell resulting from the fusion of gametes}
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