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205 Cards in this Set
- Front
- Back
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ABO blood typing
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Method of using the presence of proteins A, B, or both at the surface of red blood cells to characaterize an individual's blood. O signifies absence of both proteins.
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Abortion
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Premature, spontaneous or indiced expulsion of the embryo or fetus from uterus. Spontaneous abortion also called miscarriage.
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abscisic acid
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plant hormone that promotes stomatal closure, bud dormancy, and seed dormancy.
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abscission
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hormone induced dropping of leaves, flowers, fruits, or other parts from a plant.
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absorption
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uptake of water ans solutes from the enviorment by cell or multicelled organism; e.g., movement of nuturents, fluid, and ions across gut lining and into internal environment.
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accessory pigment
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any of a variety of light-trapping pigments that extend the range of the wavelengths for photosynthesis beyond those absorbed by chlorophylls.
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acetyl-CoA
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Coenzyme A with a two carbon fragment from pyruvate attached. In the second stage of aerobic respiration, it transfers the fragment to oxaloacetate for the Krebs cycle.
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acidity
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Of a solution, an excess of hydrogen ions relative to hydroxyl ions.
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acid
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any dissolved substance that dontes hydrogen ions to other solutes or to water molecules.
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acid rain
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wet acid decomposition; falling of rain (or snow) rich in sulfer and nitrogen oxides.
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acoelomate
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absence of a fluid filled cavity between gut and body wall.
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accoustical signal
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sounds used as a form of intraspecific communication.
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actin
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cytoskeletal protein; subunit of microfilaments.
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action potential
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abrupt, brief reversal in the resting membrane potential of a nuron and other excitable cells.
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activation energy
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For each type of reaction, the minimum amount of collision energy that will drive reactant molecules to an activated state, from which the reaction will proceed spontaneously.
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active site
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Crevice in the surface of an enzyme molecule where a specific reaction is catalyzed (made to proceed more rapidly than it would spontaneously)
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active transport
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pumping of a specifc solute across a cell membrane, through the interior of a transport protein, against its concentration gradient. Requires an energy boost, as from ATP.
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adaptation
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Of evolution, being adapted (or becoming more adapted) to a set of enviormental conditions. Of a sensory neuron, a decrease or cessation in the frequency of action potentials when a stimulus is maintained at constant strength.
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adaptive radiation
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Macroevolutionary pattern; a burst of genetic divergences from a lineage that gives rise to many new species, each adapted to using a novel resource or a new (or recently vacated) habitat.
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adaptive trait
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Any aspect of form, function, or behavior that helps the individual survive and reproduce under prevailing conditions.
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adaptive zone
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A way of life available for organisms that are physically, ecologically, and evolutionary equipped to live it, such as "catching insects in the air at night".
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adenine
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A purine; a nitrogen containing base in certain nucleotides.
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ADH
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Anti-duretic homone. Hypothalmic hormone that induces water conservation; helps control the solute concentrations and volume of the extracellular fluid.
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adipose tissue
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A coonective tissue having an abundance of fat storing cells and blood vessels for transporting fats
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ADP
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Adenosine diphosphate. Nucleotide coenzyme; typically accepts inorganic (unbound) phosphate or a phosphate group thus becoming ATP.
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aerobic respiration
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Main ATP forming pathway; proceeds from glycolysis through Kreb's cycle and then electron transport phosphorylation. Fianl electron acceptor is oxygen. Typical net energy yeild: 36 ATP per glucose molecule.
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age structure
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number of individuals in each age category for a population.
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agglutination
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Forced clumping together of nonself markers when antibodies circulating in blood chemically recognize them. Clumpingmakes bearers of those markers more easily destroyed by phagocytes. Potential problem in recipients of transfused bllod of a different type.
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aging
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Of any multicelled organism showing extensive cell differentiation, a gradual and expected deterioration of the body over time.
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AIDS
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Acquired immunodeficientcy syndrome. A set of chronic disorders following infection by the human immunodeficiency virus which destroys cells of the immune system.
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alcohol
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organic compound that includes one or more hydroxyl groups (-OH); it dissolves readily in water. Sugars are examples.
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alcholic fermentation
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One of the anaerobic ATP forming pathways. The pyruvate from glycolysis is degraded to actealdehyde, which accepts electrons from NADH to form ethanol; NAD+ needed for reactions is regenerated. Net yeild: 2 ATP.
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aldosterone
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hormone of the adrenal cortex; helps control the body's reabsorption of sodium from nephrons.
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allantois
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An extraembryonic membane. Functions in respiration and in storing of metabolic wastes of embryos of reptiles, birds, and certain mammals. In humans, the urinary bladder and placental blood vessels form from it.
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allele
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For a given gene locus, one of two or more slightly different molecular forms of a gene that arise through mutation and that code for different versions of the same trait.
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allele frequency
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For a given locus, the relative abundance of each kind of allele among all the individuals of a population.
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allergen
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any normally harmless substance that provokes inflammation, excessive mucous secretion, and often immune responses.
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allopatric speciation
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Model of what may be the most common speciation route. A phsical barrier arise and separates populations or subpopulations of a species, stops gene flow, and favors divergences that end in speciation.
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altruism
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behavior that helps other members of a species but diminsihes an individual's own chance of reproductive success.
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alveolus
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Cupped, thin-walled outpouching of respiratory bronchiole where oxygen diffuses from lungs into blood, and carbon dioxide diffuses from blood to lungs.
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amino acid
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An organic molecule with a hydrogen atom, an amino group, an acid group, and an R group, all covalently bonded to a carbon atom. Twety kinds are the subunits of polypeptide chains.
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ammonification
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process by which some soil bacteria and fungi break down nitrogenous wastes and organic remains; part of nitrogen cycle
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amnion
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An extraembryonic membrane; the boundary layer of a fluid-filled sac (amniotic cavity) in which the embryos of some vertibrate embyos grow and develop, move freely, and are protected from sudden impacts and temperature shifts.
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amniote egg
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Egg that has extraembryonic membranes and often a shell. Contributed to successful invasion of land by vertibrates.
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amphibian
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Only type of vertebrate making the transition from water to land (evolutionarily and in their embryonic development). Existing groups are salamanders, frogs, toads and caecilians.
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anaerobic electron transport
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ATP-froming pathway in which electrons stripped from an organic compound move through transport systems in the bacterial plasma membrane; an inorganic compound in the environment often serves at the final electron acceptor. Variable but always small net energy yield.
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anaerobic pathway
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metabolic pathway in which a substance other than oxygen is the final acceptor of electrons stripped from substrates.
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analogous structures
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body parts that once differed in evolutionarily distant lineages but converged in their structure and functionin response to similar environmental pressures.
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anaphase
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Of mitosis, stage when sister chromatids of each chromosome move apart to opposite spindle poles. In anaphase I of meiosis, each duplicated chromosome and its homologue move to opposite spindle poles. In anaphase II of meiosis, sister chromatids of each chromosome move to opposite poles.
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aneuploidy
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having one extra or one less chromosome relative to the parental chromosome number.
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angiosperm
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flowering plant
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animal
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multicelled heterotroph that feeds on other organisms, is motile for at least a part of life cycle, develops through embryonic stages, has tissues (except Trichoplax and sponges), and most often has organs and organ systems.
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annelid
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Type of invertibrate; a segmented worm
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annual
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flowering plant that completes its life cycle in one growing season.
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anther
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part of a stamen, pollen forms in it and is dispersed from it.
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antibiotic
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metabolic prodict of soil microbes that kills bacterial competitors for nutrients.
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antibody
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Antigen-binding receptor. Only B cells make antibodies, then position them at their surface or secrete them.
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anticodon
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sequence of three nucleotide bases in a tRNA molecule that can base-pair with a coon in a mRNA molecule.
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antigen
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Any molecular configurationthat certain lymphocytes recognize as nonself and that triggers an immune response.
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antigen-presenting cell
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Cell that possesses and bears antigen fragments, bound to MHC molecules, at its surface. The antigen-MHC complexes promote immune responses.
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Aorta
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Of vertebrates, main artery of systemic circulation; transports the volume of blood the heart pumps into it.
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apical dominance
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growth inhibiting effect of a terminal bud of lateral buds.
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apical meristem
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mass of self-perpetuating cells underlying primary growth at root tip and shoot tip.
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apoptosis
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programmed cell death. Molecular signals activate weapons of self destruction in body cells that finished thier prescribed functions or became altered, as by infection or cancerous transformation.
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appendicular skeleton
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bones of limbs, hips and shoulders
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archaebacteria
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Kingdom of prokaryotes more like eukaryotic cells than eubacteria; includes methanogens, halophiles, and thermophiles.
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archipelago
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an island chain some disatnce away from a continent.
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area effect
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idea that larger islands support more species than smaller ones at equivalent distances from sources of colonizing species
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arteriole
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type of blood vessel between ateries and capillaries. Controls over arteriolar dilation and constriction selectively distribute blood volume throughout body.
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artery
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Large diameter rapid-transport vessel with thick, muscular wall; smooths out blood pressure pulses caused by heart contractions.
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arthropod
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Inverebrate having a hardened exoskeleton, specialized body segments, and jointed appendages. Insects are examples.
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artificial selection
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Selection of traits among individuals in a population in an artificial environment, under contrived conditions.
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asexual reproduction
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Any of a number of modes of reproduction by which offspring arise from a single parent and inherit the genes of that parent only.
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atmosphere
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The volume of gases, airborne particles, and water vapor enveloping Earth.
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atom
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smallest particle unique to an element; has one or more positively charged protons, electrons, and 9except for hydrogen) electrons.
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atomic number
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number of protons in the nucleus of each atom of an element.
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ATP
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Adensosine triphosphate. Energy carrying nucleotide with adenine, ribose, and three phosphate groups. Phosphate-group transfers from ATP drive most energy-requiring metabolic reactions.
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australopith
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one of the earliest known hominids; a primate that may be on or near evolutionary road to humans.
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autoimmune response
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misdirected immune response in which lymphocytes mount an attack against normal body cells.
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autonomic nervous system
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All nerves fron centrl nervous system to the smooth muscle, cardiac muscle, and glands of viscera (soft internal organs and structures)
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autosome
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Type of chromosome that is the same in males and females of the species.
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autotroph
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Organism that makes its own organic compounds using an enviomental energy source (e.g. sunlight) along with carbon dioxide as its carbon source.
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auxin
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Plant hormone; promotes stem lenthening and responds to gravity and light.
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axial skeleton
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skull, backbone, ribs, and breastbone (sternum)
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axon
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cylindrical extension of neuron cell body, specialized for the rapid propagation of action potentials.
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B cell
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B lymphocyte; only cell that produces antibodies. Key player in immune responses.
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bacterial conjugation
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the transfer of plasmid DNA from one bacterial cell to another.
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bacteriophage
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category of viruses that infect bacterial cells
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Barr body
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In body cells of female mammals, one of either of the two X chromosomesthat was condensed to inactivate its genes.
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basal body
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A centriole which, after giving rise to microtubules of a flagellum or cilium, remains attached to its base in the cytoplasm.
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base
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any substance that accepts hydrogen atoms when dissolved in water.
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base sequence
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Particular order in which on e nucleotide base follows the next in a strand of DNA or RNA. The order is unique in at least some regions for each species.
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basophil
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Fast-acting white blood cell; its secretions (e.g. histamine) cause vasodialation during an inflammatory response.
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behavior
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Response to external and internal stimuli based on sensory, neural, endocrine, and effector components. Has a genetic basis, can evolve, and can be modified by learning.
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benthic province
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All sediments and rocky formations of the ocean bottom.
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biennial
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flowering plant that completes its growing cycle in two seasons.
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bilateral symmetry
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body plan in which lwft and right halves generally are mirror images.
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binary fission
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Asexual reproductive mode of protozoans and some other animals. The body divides into two parts of the same or different sizes.
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binomial system
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Of taxonomy, assigning a generic and a specific name to each species.
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biogeochemical cycle
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slow movement of an element from the environment, through food webs, and then bach to the environment.
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biogeographic realm
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One of six vast land areas, each with distinctive kinds and numbers of plants and animals.
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biological clock
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Internal time measuring mechanism that help's adjust an organism's daily activities, seasonal activities, or both in response to enviormental cues.
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biological magnification
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The increasing concentration of a non-degradeable or slowly degradeable substance in body tissues as it is passed along food chains.
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biological species concept
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Defines a species as one or more populations of individuals that are interbreeding under natural conditions, thaat are producing fertile offspring, and that are isolated reproductively from other such populations. Applies to sexually reproducing species only.
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bioluminescence
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Any organism flashing with flourescent light by way of an ATP-driven reaction envolving enzymes (luciferases)
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biomass
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Combined weight of all organisms at a given trophic level in an ecosystem.
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biome
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Large subdivision of a biogeographic realm, distinctive in its habitat conditions, community structure, and endemic species
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biosphere
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All regions of the Earth's waters, crust, and atmosphere in which organism's live
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biosynthetic pathway
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Metabolic pathway by which organic compounds are synthesized.
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biotic potential
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Of population growth for a given species, the maximum rate of increase per individual under ideal conditions
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bipedalism
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Habitually walking upright on two feet, ,as by ostriches and hominids
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bird
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only vertebrate that produces feathers; evolutionarily linked with dinosaurs.
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blastocyst
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Type of blastula. Blastomeres form a surface layer, a cavity filled with their own secretions, and an inner cell mass.
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blastomere
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One of the small, nucleated cells that form during cleavage of animal zygote
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blastula
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An early outcome of cleavage; a number of blasomeres enclosing a fluid filled cavity.
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blood
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Fluid connective tissue of water, solutes, and formed elements (blood cells and platelets). Blood transports substances to and from cells, and helps maintain internal environment.
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blood pressure
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Fluid pressure, generated by heart contractions, that circulates blood.
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blood-brain barrier
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Mechanism that controls which solutes enter cerebrospinal fluid; helps protect the brain and spinal cord.
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bone
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Vertebrate organ with mineral hardened connective tissue (bone tissue); helps move body, protects other organs, stores minerals, Some (e.g. breastbone) produce blood cells.
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bottleneck
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Severe reduction in population size brought about by intense selection pressure or by a natural calamity.
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Bowman's capsule
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Cup-shaped portion of a nephron that recieves water and solutes being filtered from blood.
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brain
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Of most nervous systems, integrating center that recieves and processes sensory input and issues coordinated commands for responses muscles and glands.
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brain stem
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Of vertebrates, nervous tissue that evolved first and still persists in the hindbrain, midbrain and forebrain.
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bronchiole
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Finely branched airway; part of the bronchial tree inside the lung.
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bronchus
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Tubular airway that branches from trachea and leads into lungs
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brown alga
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Photoautotrophic protistan with chlorophylls a, c1, c2, and carotenids (e.g. fucoxanthin). Mostly marine. Rnage in size from microscopic to giant multicelled kelps.
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bryophyte
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Nonvascular land plant requiring free water to complete fertilization. Haploid dominanance in life cycle. Cuticle and stomata present in some species. A moss (e.g., peat moss), liverwort, or hornwort.
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bud
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Undeveloped shoot, mainly meristematic tissue. Small protective scales often cover it.
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buffer system
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a weak acid and the base that forms when it dissolves in water. The two work as a pair to counter slight shifts in pH.
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bulk flow
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In response to a pressure gradient, a movement of more than one kind of molecule in the same direction in the same medium, as in blod, sap, or air.
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C3 plant
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Plant that uses three carbon PGA as the first intermediate for carbon fixationduring the second stage of photosynthesis.
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C4 Plant
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Plant that uses oxaloacetate (a four-carbon compound) as the first intermediate for carbon fixation during the second stage of photosynthesis. CO2 is fixed twice, in two cell types. Carbon dioxide accumulates in leaf and helps counter photrespiration.
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Calvin-Benson cycle
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Cyclic, light-independant reactions; "synthesis" part of photosynthesis. Uses ATP and NADPH from light dependant reactions. RuBP or some compound to which carbon has been affixed is rearranged and regenerated, and a sugar phosphate forms.
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CAM plant
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Type of plant that conserves water by opening stomata only at night, when it fixes carbon dioxide by means of a C4 pathway.
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camouflage
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Adaptaion in coloration, form, patterning, or behavior that helps predators or prey hide in the open (blend with their surroundings) and escape detection.
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cancer
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Malignant tumor; mass of cells that have grossly altered plasma membrane and cytoplasm, grow and divide abnormally, and adhere weakly to home tissue (which leads to metastasis). Lethal unless eradicated.
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capillary, blood
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blood vessel with thin endothelial wall and small diameter; functions in the exchange of carbon dioxide, oxygen, and other solutes between blood and interstitial fluid.
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capillary bed
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Diffusion zone, consisting of great numbers of capillaries, where blood and interstitial fluid exchange substances.
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carbohydrate
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Molecule of carbon, hydrogen and oxygen mostly in a 1:2:1 ratio. Carbohydrates are structural materials, energy stores, and transportable energy forms. Monosaccharide, oligosaccharide, or polysaccharide.
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carbon cycle
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An atomospheric cycle. Carbon moves from its largest reserviors (sediment,rocks and the ocean), through the atmosphere (mostly as CO2), through food webs and back to the reserviors.
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carbon dioxide fixation
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First-step of light-independent reactions. Enzyme action affixes carbon (from CO2) to RuBP or to some other compound for entry into the Calvin-Benson cycle.
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carcinogen
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any substance or agent that can trigger cancer
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cardiac pacemaker
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Sinoatrial node (SA); basis of normal rate of heartbeat. Self-excitatory cardic muscle cells spontaneously generate rythmic waves of excitation over heart.
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cardiac cycle
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sequence of mucle contraction and relaxation in one heartbeat.
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cardiovascualr system
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Organ system that has blood, one or more hearts and blood vessels.
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carnivore
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Animal that eats other animals
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caroteniod
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An accessory pigment. Different kinds absorb blue-violet and blue-green wavelengths, the energy of which is transferred to chlorophylls. They reflect yellow, orange, and red wavelengths.
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carpel
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Female reproductive part of a flower. One of more carpels make up the ovary and a stigma and often a style.
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carrying capacity
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The maximum number of individuals in a populpation (or species) that a given environment can sustain indefinately.
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cartilage
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Connective tissue with solid, pliable intercellular material that resists compression.
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Casparian strip
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Narrow, waxy, impermeable band between walls of abutting cells making up root endodermis and exodermis.
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cDNA
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DNA molecule copied from a mature mRNA transcript bt reverse transcription.
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cell
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smallest living unir; organized unit with a capacity to survive and reproduce on its own; given DNA instructions, energy sources and raw materials.
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cell count
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The number of cell of a given type in one microliter of blood.
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cell cycle
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Events by which a cell increases in mass, roughly doubles its cytoplasmic components, duplictes its DNA, then divides its nucleuos and cytoplasm. Extends from the time a cell forms until it completes division.
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cell differentiation
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Key development process. Different cell lineages become specialized in their composition, structure, and function by activating and suppressing some fraction of the genome in different ways.
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cell junction
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Site that joins cells physically, functionally or both (e.g., tight junction in animals; plasmoderma in plants).
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cell plate
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Disklike structure that forms in a plant cell after uclear division; becomes a crosswall, with new plasma membrane on both surfaces that divides the cytoplasm.
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cell theory
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Theory stating that all organisms consist of one or more cells, the cell is the smallest unit with a capacity for indeoendent life, and all cells arise from preexisting cells.
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cell wall
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Of most bacteria, many protistan and fungal cells, and plant cells, the outer-most, semirigid, permeable structure that helps the cell retain its shape and resist rupturing when the internal fluid pressure increases.
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central nervous system
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brain and spinal cord
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central vacoule
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Large, fluid-filled organelle of living, mature plant cells. Stores amino acids, sugars, ions, and toxic wastes. As it enlarges during growth, it forces the primary cell wall to expand and cell surface area to increase.
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centriole
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structure that gives rise to microtubules of cilia and flagella.
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centromere
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constricted portion of each chromosome; ocation of a kinetochore to which spindle microtubules become attached.
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cephalization
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The concentration of sensory structures and nerve cells in the head; occured during the evolution of bilateral animals.
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cerebellum
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hind brain region with reflex centers for maintaining posture and smoothing out limb movements
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cerebral cortex
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Thin surface layer of cerebral hemispheres; recieves, integrates, and stores sensory information; coordinates responses
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cerebrospinal fluid
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clear, extracellular fluid, enclosed in a continous system of canals and chambers, that baths and protects the brain and spinal cord
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cerebrum
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part of the forebrain that integrates olfactory input, selects motor responses. In mammals, it evolved into the most complex integrating center
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channel protein
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transport protein that serves as an open or gated channel where ions and other solutes move across a cell membrane
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chemical bond
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a union between the electron structures of two or more atoms or ions
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chemical energy
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potential energy of molecules
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chemical synapse
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narrow cleft between a presynaptic neuron and a postsynaptic cell. Molecules of neuro transmitter diffuse across it
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chemicosmotic theory
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idea that an electrochemical gradient drives ATP formation. H+ accumulates in a membranous compartment, then flows out through proteins (ATP synthases) in response to concentration and electric gradients. The flow drives the attachment of onorganic phosphate to ADP
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chemoautotroph
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type of bacterium that can autosynthesize its own organic compounds using only carbon dioxideas the carbon source and an inorganic substance as the energy source
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chemoreceptor
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sensory receptor that detects chemical energy (ions or or molecules dissolved in the fluid bathing it)
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chloroflourocarbon
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compound of chlorine, flourine, and carbon that has been contributing to ozone thinning
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chlorophyll
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main photosynthetic pigment, absorbs violet to blue and red wavelengths but transmits green
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chloroplast
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the organelle of photosynthesis in plants and many protistans
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chordate
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animal with a notochord, dorsal hollow nerve cord, pharnyx, and gill slits in pharnyx wall during at least part of its life cycle
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chorion
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type of extraembryonic membrane that becomes part of the placenta. Villi (absorptive structures) form at its surface and facilitate exchanges of substances between the embryo and mother
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chromatid
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of a duplicated eukaryotic chromosome, one of two DNA molecules (with associated proteins) attached at centromere. Mitosis or meiosis separates them; each becomes a separate chromosome
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chromatin
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a cell's collection of DNA all of the proteins associted with it
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chromasome
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of eukaryotic cells, a DNA molecule, duplicated or unduplicated, with a profusion of associated proteins. Of prokaryotic cells (bacteria), a circular DNA molecule with few, if any, proteins attached
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chromosome number
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all chromosomes in a given type of cell
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cilium
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plural cilia, short motile or sensory structure projecting from surface of certain eukaryotic cells; its core is a 9 + 2 array of microtubules
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circadium ryhthm
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cycle of physiological events completed every 24 hours or so independently of environmental change
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circulatory system
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organ system that moves substances to and from cells, and often helps stabilize body tempersture and pH. Typically consists of a heart, blood vessels and blood
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cladogram
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evolutionary tree diagram with groups arranged by branch points to show relative relationships. Groups closer together share a more recent common ancestor than those farther apart
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classification scheme
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a way of organizing and retrieving information about species
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cleavage
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early stage of animal development. Mitotic cell divisions divide a fertilzed egg into many smaller, nucleated cells; original volume of egg cytoplasm does not increase
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cleavage furrow
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ringlike depression defining cleavage plane for dividing animal cells
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cleavage reaction
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enzyme action that splits a molecule in teo or more parts; hydrolysis is an example
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climate
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for a specified region, the prevailing weather conditions (e.g., temperature, cloud cover, wind speed, rainfall, and humidity).
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climax community
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array of species that has stabilized under prevailing habitat conditions
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climax pattern model
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idea that physical conditions and other environmental factors often vary in their influence over a large region, so that stable communities other than the climax stage may also persist in that region
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cloaca
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chamber or duct in last portion of gut of some animals that also serves in excretion, reproduction, and sometimes respiration
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cloning vector
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plasmid that has been modified in the laboratory to accept foriegn DNA
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club fungus
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fungus with club shaped cells that produce and bear spores
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cnidarian
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radial invertibrate at tissue level of orgaanization; the only nematocyst producer. Medusae and polyps are typical forms
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coal
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non-renewal energy source that formed over 280 million years ago from submerged, undecayed, and compacted plant remains
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codominance
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In heterozygotes, simultaneous expression of a pair of non-identical alleles that specify different pheno types
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codon
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mRNA base triplet; its linear sequence corresponds to a linear sequence of animo acids in a polypeptide chain. Of 64 codons, 61 code for amino acids; three of these are also sart signals for translation , 1 is a stop signal fro translation
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coelum
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cavity lined with peritoneum between the gut and body wall of most animals
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coenzyme
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nucleotide that acts as an enzyme helper; it accepts electrons and hydrogen atoms stripped from substrates at a reaction site and transfers then to another reaction site
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