Absorbance: The ability to take up electromagnetic radiation by objects; different wavelengths of the visible light spectrum have different absorbances and appear as different colors.
Absorption spectrum: The particular wavelengths of light that are absorbed by objects, e.g. pigment molecules, measured by a spectrophotometer.
Accessory pigments: Pigments that expand the accessible wavelengths that can be absorbed and used in photosynthesis, e.g. carotene (absorbs between 460 and 550nm, appears red, orange, or yellow) and phycocyanin (absorbs between 550 and 640 nm, appears blue).
Acetylcholine: A neurotransmitter secreted by motor neurons.
Acetylcholinesterase: An enzyme that inactivates acetylcholine.
Acid Rain: Also called acid precipitation or acid deposition, acid rain is precipitation containing harmful amounts of nitric and sulfuric acids formed primarily by nitrogen oxides and sulfur oxides released into the atmosphere when fossil fuels are burned
Action Potential: An electrochemical change that occurs across the cell membrane of a neuron.
Action Spectrum: Rate of activity in relation to wavelength of light, e.g. photosynthesis most active in blue and red parts of the visible spectrum
Active Site: Specific location on an enzyme in which the substrate molecule(s) fit(s).
Adaptation: An inherited trait thatenables an organism to survive a particular environmentalchallenge.
Adaptive Radiation: The divergence of many new species from an ancestral species, usually a rapid process, often tied to the colonization of new environments.
Adipose Tissue: Aggregations of fat cells in animals; white adipose tissue used for energy storage; brown adipose tissue used to release heat energy.
Aerobic (cellular) respiration: A series of metabolic reactions grouped into three subpathways.
agar: an enriched gelatinous media on which various microorganisms can grow
Algal blooms: Unusually high growth and biomass of various types of simple aquatic plant-like organisms (e.g. dinoflagellates, cyanobacteria), usually attributed to excess nutrient levels (nitrogen or phosphorus), glycolysis, Krebs cycle and electron transport/oxidative phosphorylation), occurring in the cells of most organisms, to convert food molecules (e.g. sugars like glucose) into usable energy (ATP). Some of the compounds involved in respiration also provide links to other metabolic pathways, such a
Alleles: Alternate forms of a gene, reflecting differences in the DNA nucleotide sequence; often described in terms of their expression in an organism.
Alternative Hypothesis: A second hypothesis to be considered and tested simultaneously with the first.
Amino acids: The building blocks of protein; 20 different amino acids exist naturally in organisms.
Analysis: To determine whether the results of your experiment are meaningful, one performs some sort of analysis that lets one see trends or patterns in the data.
Anoxia: Depletion of dissolved oxygen levels to near zero by respiration of algae and decomposers (bacteria and fungi), often an end result of large algal blooms as the algae die and decompose.
Antibody: Protein that B cells secrete that recognizes and binds to foreign antigens, disabling them or signaling other cells to do so.
Antigen: The specific parts of molecules that elicit an immune response.
Apoptosis: Genetically programmed cell death; normal part of embryonic development in animals.
Asexual Reproduction: Reproduction by cell division without exchange of genetic material.
DNA: Deoxyribonucleic acid, the double-stranded molecule that comprises the genetic material in virtually all organisms; organized into chromosomes and stored in the nucleus in eukaryotes.
Dominant Allele: An allele that masks the expression of another allele.
Assumptions: In every experiment assumptions are made which are very basic and broad, e.g. Laws of Nature are same across time and space or events in the natural world have natural causes or specific to experiment e.g. Insects cannot see infrared.
ATP: Adenosine triphosphate, an energy carrier; formed either by substrate-level phosphorylation (a phosphate group is directly transferred from another molecule to ADP) or by oxidative phosphorylation (a free phosphate is attached to ADP by chemiosmosis).
Autosomes: Non-sex chromosomes.
Autotroph: Types of organisms that can manufacture energy rich organic molecules from inorganic compounds such as water and carbon dioxide.
Avoidance: Short or long-term strategies for avoiding extremes of heat and cold, e.g.burrowing, dormancy.
Axon: A long, thick extension of a neuron that sends messages away from the cell body of the neuron.
Base Pairs: Two bases which form a "rung of the DNA ladder." A DNA nucleotide is made of a molecule of sugar, a molecule of phosphoric acid, and a molecule called a base. The bases are the "letters" that spell out the genetic code. In DNA, the code letters are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine, respectively. In base pairing, adenine always pairs with thymine, and guanine always pairs with cytosine.
Bile: Chemical that assists in fat digestion produced by the liver and gall bladder.
Biodiversity (Biological Diversity): The total variety of living things on Earth, including genetic variation in populations and the variety of species and ecosystems.
Biogeochemical cycle: Complex global-scale recycling of materials (e.g. water, carbon, nitrogen, and phosphorus) on Earth, involving varying amounts of biological, geological, and chemical transformations.
Biomagnification: Tendency for certain chemicals to increase in concentration at higher trophic levels, usually this concentration results in expression of toxicity at these higher trophic levels; e.g. DDT.
Biomes: Distinctive types of communities and ecosystems that are recognizable over largegeographic areas.
Biotechnology: General term referring to manipulation of genetic material by humans; genetic engineering; insertion of genes into different species, alteration of gene sequences.
Camouflage: Color patterns in organisms that allow them to blend in with their environment.
Cancer: Disease in which some of the body¹s cells divide uncontrollably; many factors trigger formation of cancerous cells, ranging from viral infections to environmental damage (e.g. smoking, exposure to UV light) to genetic risk factors.
Carcinogens: Substances that cause cancer; usually carcinogens are mutagens, which is how they function to cause cancer.
carotene: an orange pigment involved in photosynthesis
Carrying capacity: The population that can be sustained indefinitely in a particular environment.
Cell: The basic unit of life, containing enzymes, membranes, genetic material and, in eukaryotes but not prokaryotes, internal membrane-bound specialized compartments called organelles.
Cell Cycle: The life cycle and activities of a single eukaryotic cell from one division to the next; includes various phases (G1, S, G2, and M) that have different functions.
Fermentation: A series of biochemical reactions required to keep glycolysis going in the absence of oxygen.
Fitness: A measure of the number of surviving offspring in the next generation; greater fitness = greater reproductive success.
Flagellum: A long whiplike appendage a cell uses for motility, composed of microtubules
Food Web: A complex of interrelated food chains in an ecological community. Also called food cycle
Gall Bladder: Organ in the human digestive system that produces and stores bile.
Cell Division: The process by which a single cell divides into two daughter cells; usually includes the division of the genetic material as well as the cytoplasm; mitosis and cytokinesis in eukaryotes, prokaryotic fission in prokaryotes.
Cell Growth: The increase in size exhibited by most cells between cell division events.
Cell Membrane: A selectively permeable fluid barrier surrounding cells and organelles.
Cell Wall: A thin membrane around the cytoplasm of a cell; controls passage of substances in and out of the cell (SEE Cell Membrane)
Chemiosmosis: A way to make ATP by moving H+ against concentration gradient across inner mitochondrial membrane during electron transport, then allowing the H+ to flow back through a channel protein. Energy inherent in H+ flow serves to add a phosphate group to ADP.
Chlorophyll a: Primary photosynthetic pigment in all organisms except bacteria; absorbs red and orange (600-700 nm) and blue and violet (400-500 nm).
Chloroplast: Eukaryotic cellular organelle that contains the machinery for operation of photosynthesis.
Chromatid (sister chromatids): Replicated chromosome that consists of two identical sequences of double-stranded DNA, joined at a constricted region called the centromere; sister chromatids divide and separate during mitosis and meiosis.
chromatography: a method for separating mixtures using liquid and stationary media. Because the components of the sample differ in solubility they separate while traveling through the stationary meduim
Chromosome: Rod-shaped structure in the eukaryotic cell nucleus consisting of a continuous molecule of double-stranded DNA wrapped with protein.
Cilium: A microscopic hairlike process extending from the surface of a cell or unicellular organism. Capable of rhythmical motion, it acts in unison with other such structures to bring about the movement of the cell or of the surrounding medium
Climate: The long-term average weather in a given area, includes temperature range and precipitation amounts.
Codominance: Expression of two different alleles in heterozygotes; e.g ABO blood type alleles.
Codon: Three-letter nucleotide sequence that codes for an amino acid.
Coevolution: Occurs when two or more species (often predators/herbivores and prey/plants) mutually influence each others evolution through natural selection.
Co-factors: Vitamins in the diet that aid enzyme function in energy metabolism.
Community (Biotic): All the populations (of individual species) living in a given area.
Compentent Cells: Cells that accept the cloning vector.
Competition: Process in which individuals or species live with one another for resources in order to survive.
Complementary Strands: The double strands of DNA come together by thehydrogen bonding of adenine on one strand and thymine on the other, cytosine on one strand and guanine on the other. Therefore, if the nucleotide sequence of one strand is known, the sequence for the other can be constructed using these rules for pairing (adenine goes with thymine; cytosine goes with guanine).
Concentration Gradient: A difference in concentration (number of molecules per volume) of a substance between two points in space, e.g. on opposite sides of a cell membrane. (See also gradient).
Gene: A sequence of DNA that specifies a sequence of amino acids that forms a particular polypeptide.
Genetic Code: The correspondence between the chemical language of mRNA and the resulting polypeptide; code is read in sets of three RNA letters (a codon, e.g. AGC > serine).
Genotype: Genetic makeup of an individual.
Germ Cells: Cells that undergo meiosis and give rise to gametes; egg (female gametes) and sperm (male gametes) in animals.
Golgi Apparatus: A system of flat, stacked membrane-bound sacs where cell secretions are sorted and packaged into vesicles for exocytosis.
Conduction: The transfer of energy (in this case heat) from one place to another directly (by contact). Heat flows down a gradient from warmer to cooler areas. The grater the difference in temperature, the faster the transfer of heat.
Conjugation: A form of gene transfer (sexual reproduction) in bacteria.
Control Group: The individuals or subjects in the control group(s) are subjected to exactly the same treatment and conditions as those in the experimental group(s)EXCEPT for the application of the experimental manipulation.
Control Variable: A control variable is any of the factors that you choose to hold constant for all groups to insure that it is not that variable producing the effect, but instead it is the experimental variable that has the effect.
Controlled Experiment: In a controlled experiment, the experimenter determines the levels or amount of the variable of interest to apply. At least two groups are involved and one group is not 'exposed' to the factor of interest.
Convection: The transfer of heat energy by mass movement of a fluid (gas or liquid). Fluids in motion (like wind) facilitate heat transfer by maintaining a high heat gradient between the solid and the new portion of fluid.
Core Body Temperature: This is the internal temperature of an animal. When you take your temperature, the thermometer is not held on the surface of your skin, it is placed inside your body (somewhere!).
Countercurrent exchange: Passage of heat from one blood vessel to another.
Courtship Display: Stereotyped, elaborate, and conspicuous behaviors that prevent mating with the wrong species and overcome aggression of the opposite sex long enough for mating to occur.
Crossing Over: The exchange of homologous chromosome segments during prophase I of meiosis.
Crypsis: Concealment. An organism that is cryptic has coloration and markings that resemble the substrate or other surroundings which help to conceal it from other organisms.
Cystic fibrosis: An autosomal recessive genetic disorder; affected individuals inherit two copies of a defective gene (one from each parent) that codes for the CFTR protein (functions to transport chloride ions across cell membranes).
Cytokinesis: The division of the cytoplasm in eukaryotic cells, following the nuclear division (mitosis or meiosis).
Cytoplasm: The jellylike fluid in which cell structures are suspended
Death rate/mortality: The rate at which death occurs in a population, e.g., # deaths/10,000 individuals in the population/year.
Decomposers: Organisms that consumes feces and dead organisms
Dendrite: Short, branched extension of a neuron that receives messages from other neurons and transmits messages toward the cell body.
Dependent Variable: The dependent variable is the variable in which you are measuring changes in response to the independent or experimental variable.
Dialysis: The separation of smaller molecules from larger molecules by selective diffusion through a semipermeable membrane
Differentiation: The process by which cells become specialized in their structure and function, by restricting expression of certain genes.
Diffusion: The movement of a substance from an area of higher concentration to an area of lower concentration
Digestion: The breakdown of food into smaller subunits so that energy can be extracted via the body¹ metabolic pathways (e.g. cellular respiration).
Diploid: Two sets of chromosomes.
Direct Competition: Competition that involves behaviors directed at other organisms to prevent their access to a resource (Contest competition).
Disruptive Coloration: A distinct coloration which delays recognition of the whole animal by attracting the attention of the observer to certain elements of the color pattern.
Dissolved Oxygen: A measure of oxygen contained in the water. Adequate dissolved oxygen is critical to most aquatic organisms and is one of the more important indicators of environmental health
Double Blind Experiment: While the subjects rarely if ever know whether they are in the control or experimental group, in a double-blind experiment the person collecting data does not know either until after data are collected to avoid bias.
Ecological Diversity: The variety of different types of ecosystems on Earth, which in turn support a wide variety of species.
Ecosystem: All of the organisms (communities) in a defineable area + the physical environment of that area. Examples - pond, forest
Ectotherm: An animal that obtains body heat primarily from its external environment.
Electron Transport: Passing of electrons (taken from some organic chemical) along a series of proteins embedded in a cell membrane, e.g. the inner mitochondrial membrane. This series of proteins is referred to as the electron transport chain (ETC).
Encounter Rate: The frequency at which a predator detects prey.
Endocrine System: Glands and cells that secrete hormones.
Endosymbiosis: Literally, a symbiotic relationship between members of two species in which the smaller symbiont lives inside the larger one. Usually used to refer to symbionts that live inside a eukaryotic cell.
Endotherm: An animal that attains most of its heat internally from its metabolism.
Enzyme Inhibitor: A chemical that prevents or slows enzyme activity, e.g. by changing its shape or blocking the active site.
Enzymes (Proteins): Macromolecules made up of a genetically-determined linear sequence of amino acids, having a specific, environmentally-sensitive 3-dimensional shape, that catalyze (speed up) very specific chemical reactions.
Epidemic: Sudden rapid spread or growth of a disease.
Essential Micronutrients: Chemicals required for metabolism that are not synthesized by the organism; must be obtained in diet; vary from species to species; e.g. 8 of the 20 amino acids needed by human.
Estuaries: Transitional coastal ecosystems where fresh water from rivers and streams meets and mixes with the salty waters of the ocean; wetlands, marshes; typically have high primary productivity and support commercial and sport fisheries.
Eukaryote: A type of organism whose cells have a membrane-bound nucleus and other internal membrane-bound compartments (organelles).
Eutrophication: Slow (thousands of yrs) natural process in lakes, ponds, and coastal waters; involves build up of sediments and nutrients (N and P) and plant/algae biomass;often decreased species diversity;cultural if accelerated by fertilizer, sewage, runoff.
Evaporation: Loss of water in the form of a vapor. Because evaporation of water requires a great deal of heat, heat is transferred from an organism to its surroundings as water evaporates from the organismís surface.
Evaporative Cooling: Heat loss by evaporation of fluid from the body's surface.
Evolution: A process of change through time in the genetically determined characteristics of organisms, at the level of populations (natural selection and genetic drift), speciation and emergence of new types of organisms.
Exocytosis: Fusion of vesicles with the cell membrane that releases cell products or wastes outside of the cell.
Exotic (introduced, non-native) Species: Species that enter a new ecosystem, often introduced accidentally or intentionally, by humans; often disrupt ecological diversity and alter ecosystem function, if exotic species have no natural predators.
Experimental Group: The individuals in the experimental group are treated to some non-zero level of the factor of interest.
Experimental Variable: The experimental variable is the item or factor you wish to test to see if it affects the subjects in the way you predict based on your hypothesis.
Feedback loop: Means of regulating the timing and output of cellular metabolism; production of certain chemicals, often enzymes, can act to turn pathways on or off.
Exponential population growth: Population growth which is rapid due to an ever-expanding base of reproductive individuals. The geometric increase of a population as it grows in an ideal, unlimited environment.
Fluid Mosaic Model: The theory that describes cell membranes as a phospholipid bilayer in which are embedded proteins with a variety of functions. This model is consistent with selective permeability, chemiosmosis, electron microscopy, etc.
Genetic Counseling: Health care profession in which counselors help families assess their risk of having children with genetic disorders, based on a variety of genetic tests and understanding of the family¹s genetic history (pedigree).
Genetic Diversity: The total variety of alleles for all genes in population, communities, and all species worldwide; important for the processes of natural selection, biotechnology and agriculture.
Glycolysis: First (and most evolutionarily ancient) series of biochemical reactions of cellular respiration in which 6-carbon sugars (e.g.glucose) are split to 3-carbon compounds with a net yield of 2 ATP; can operate without oxygen in conjunction with fermentation.
Good Genes Hypothesis: Male courtship and appearance provide information to females about the health and condition of a would-be mate but states that the benefit from mating with a robust and healthy partner lies in the acquisition of genes conducive to offspring survival.
Gradient: A gradient is the difference in a variable with distance. e.g. Temperature gradient, chemical gradient
Grana: Stacks of thylakoid membranes that contain the chlorophyll pigments.
Growth factors: Chemicals that act as signals for cells to grow and/or divide; e.g. epidermal growth factor, cyclins.
Guard Cells: One of a pair of epidermal cells that open and close stomata in plants by gaining and losing turgor pressure
Handicap Hypothesis: Females prefer the trait (e.g. long tail, bright coloration, etc.) because it is a handicap to the male and therefore acts as a reliable signal of a male's genetic quality.
Handling Time: The time it takes for an animal to capture and eat its prey.
Haploid: One set of chromosomes.
Heat Radiation: Heat transfer between two objects in the absence of direct contact. All objects above absolute zero emit radiation and receive radiation from their surroundings.
Heritability: The amount of variation for a trait that can be attributed to the genes.
Heritable Traits: Observed traits or characters that have some genetic component and thus are passed from one generation to the next from parents to offspring.
Heterozygous: Individuals who carry two different alleles for a trait.
Hierarchical Classification System: The Hierarchical order of Kingdom, Phylum, Class, Order, Family, Genus, Species.
Homeostasis: The ability of organisms to maintain a stable range of internal conditions in the face of a wider range of temperature and chemical conditions in the external environment.
Homeotherm: Animals that maintain a reasonably constant body temperature independent of the immediate environmental temperature.
Homologous Chromosomes: Pairs of chromosomes that carry genes for the same traits.
Homozygous: Individuals who carry two of the same alleles for a trait.
Hormone: Chemical messengers of the endocrine system that regulate and coordinate an organism¹s physiology, often proteins or lipids.
Human Genome Project: Multi-scientist project to map the nucleotide sequence and location of each human gene
Hypertonic: The solution on one side of a membrane where the solute concentration is greater than on the other side
Hypothalamus: Part of the forebrain that links the nervous and endocrine systems; regulates many vital functions (e.g. body temperature), responsible for maintaining homeostasis.
Hypothesis: To answer some general or specific question, one develops a hypothesis, a tentative causal explanation, based on the observations that have been made.
Hypotonic: The solution on one side of a membrane where the solute concentration is less than on the other side
Immunity: A condition of being able to resist a particular disease especially through preventing development of a pathogen or its products.
Incomplete Dominance: Heterozygous phenotype is intermediate between the two homozygous phenotypes.
Independent Assortment: Random assortment of maternal and paternal chromosome homologues during metaphase I of meiosis; results in different allele combinations in different gametes.
Independent/Manipulated/Predictor Variable: An independent variable is an experimental variable or variable of interest that the experimenter typically is able to manipulate, i.e. set the values, and serves as the predictor for the result.
Infectious disease: A disease caused by an infective agent, a parasite which may be prokaryotic or eukaryotic, unicellular or multicellular.
Insulation: A layer with a limited capacity for heat transfer, like fur.
Interpret/Draw Conclusions: One interprets or draws conclusions based on the data collected and the works of others. Interpretation leads to a statement as to whether the data support the hypothesis or not. Additionally one speculates and suggests new hypotheses.
Intrasexual Competition: Competition between the sexes
Intrinsic Rate of Increase: The difference between the birth rate and the death rate, the maximum population growth rate; population growth under ideal conditions.
Ion: An atom that has lost or gained electrons, giving it an electrical charge
Isotonic: When solute concentration is the same on both side of a membrane
J-Shaped Curve: The shape of a curve depicting exponential population growth.
K+ channel: Protein that allows potassium ions to pass through a membrane.
Krebs Cycle (Citric Acid Cycle): The stage in cellular respiration that completely metabolizes the products of glycolysis.
Law of Q10: The increase of a rate of reaction as a function of temperature. As a general rule, reaction rates double with every 10o C change in temperature.
Ligase: An enzyme that catalzes formation of covalent bonds in the DNA sugar-phosphate backbone
Light Dependent Reaction: Photosynthetic pathways that use absorbed light energy to make ATP (photophosphorylation) and NADPH.
Light Independent Reaction: Chemical reactions of photosynthesis that do not require light energy directly to transform (or fix) carbon dioxide into organic carbon compounds.
Limiting Factors: Physical or biological factors that limit the size of populations; Density-Independent (climatic factors) or Density-Dependent (predation, disease, etc.)
Lipases: Enzymes that break down lipids into fatty acid subunits.
Lipids: Organic macromolecules composed mostly of C, O, and H and not soluble in water; necessary for metabolism; many function as energy storage (fats and oils), others comprise the cell membrane, others function as receptors and hormones.
Liver: Largest organ in the human body; functions in digestion by producing bile, storing glycogen and vitamins; also important in detoxifying the blood.
Lymphatic System: A companion circulatory system to the blood that acts as a filter for infections and absorbs lipids from the digestive system.
Macronutrients: Carbohydrates, fats, and proteins obtained from the diet.
Macrophage: A very large, wandering phagocyte; an amoeboid cell that moves through tissue fibers, engulfing bacteria and dead cells by phagocytosis.
Mate Choice: The mate that is chosen based on physical attributes.
Mating Strategy: A number of different strategy use to increase the chance of ones genes being past on.
Mating System: Social organization of a breeding group, may be species-specific or vary according to conditions.
Meiosis: Cell division that halves the number of chromosome sets; part of sexual reproduction.
Metabolic Rate: The rate at which an organism's metabolism takes place.
Metabolism: The sum of an organismís biochemical reactions that acquire and use energy.
Metastasis: Cancer cells that leave the original tumor and spread the cancer, usually through the bloodstream, to new parts of the body.
Mimicry: Resemblances in physical appearance between species, often only distantly related in an evolutionary sense; often associated with defenses against predation.
Missense Mutation: A mutation that changes a codon specifying a certain amino acid into a codon specifying a certain amino acid into a codon specifying a different amino acid
Mitochondria: An organelle present in all eukaryotic cells whose main function is to carry out aerobic respiration and make ATP; surrounded by a double membrane and contains own ribosomes (involved in protein synthesis) and DNA (genetic material).
Mitosis: Cell division of a parent cell that yields two genetically identical daughter cells.
Mode Of Action: The method by which something works.
Molecule: The smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atoms; a group of like or different atoms held together by chemical forces
Monogamy: A breeding unit of one male and one female, can be lifetime but not necessarily; favored if offspring have higher survival rates when both parents provide care.
Mortality: Death of organism.
mRNA: MessengerRNA, contains the genetic message transcribed from the DNA.
Mutagens: Agents that cause mutation, any change in the DNA structure; e.g. ultraviolet light, chemicals like caffeine, x-rays; mutagens function as carcinogens.
Mutation: Any change in a gene or chromosome.
Na+ channel: Protein that allows sodium ions to pass through a membrane.
Na+/K+ Pump: A mechanism that uses energy released from splitting ATP to transport Na+ out of cells and K+ into cells.
Natural Selection: Differential survival and reproduction of organisms whose genetic traits are better adapted to the organisms particular environment. Considered the main mechanism of adaptive evolution.
Neuron: A nerve cell, consisting of a cell body, a 'sending' axon and many 'receiving'dendrites.
Neurosecretions: Release of hormones from neurons that then travel to their target cells.
Neurotransmitter: A chemical passed from one neuron to receptors on another neuron or a muscle or gland cell; alters membrane permeability, either provoking or preventing an action potential.
Niche: A species way of life; includes habitat, resource use, interactions with other species.
Nitrogen: N - Nitrogen makes up 78 percent of air by volume, and is obtained by liquefaction and fractional distillation of air. Nitrogen is colorless, odorless, and generally inert, yet when combined with other molecules is very active
Nondisjunction: Failure of one or more pairs of chromosomes to separate during meiosis.
Nonsence Mutation: A point mutation that alters a codon that encodes an amino acid to one that encodes a stop codon.
Nucleoid: The part of a prokaryotic cell where the DNA is located
Nucleolus: A structure within the nucleus where RNA nucleotides are stored
Observation: Some that is detected or measured through 5 senses (or their extensions).
Oncogene: Gene that normally triggers cell division; when overexpressed, alters the cell cycle and causes cancer.
Optimal Foraging Theory: That selection favors a strategy in which a predator utilizes prey in a manner that optimizes net energy gain per unit feeding time.
Non-Point Source Pollution: Diffuse entry or introduction of pollutants into an ecosystem from a variety of sources and locations; often difficult to monitor and control; e.g. runoff from farmland into rivers and lakes; largest remaining class of water pollution in the U.S.
Nucleotides: Building blocks of nucleic acid (such as DNA), each containing a sugar, phosphate group, and nitrogenous base (adenine - A, guanine - G, cytosine - C, thymine - T in DNA; uracil ­ U instead of thymine in RNA).
Observational Experiment: The experimenter cannot set the exact values of the experimental variable or select the subjects for each groupbecause it: is ethically unacceptable, physically impossible, includes too many variables so test by correlation and conclusions less strong.
Organelle: Compartment surrounded by one or more membranes and having a specific function(s).
Osmosis: Passive diffusion of water through a semipermeable membrane
Oxidative Phosphorylation: Formation of ATP using chemiosmosis in mitochondria.
Paradigm Shift: A paradigm is a theory of such general importance or usefulness that it shapes the way science is conducted. A paradigm shift is when a paradigm is found to be in error or no longer useful and is replaced by another.
Parasitism: A symbiotic relationship in which one member lives at the expense of the other, called the host.
Parental Investment: Parent provides time, energy, and resources to survival of its offspring.
Pathogen: A parasite that causes disease in the host.
PCR: Polymerase Chain Reaction; technique that allows the replication of millions of copies of a small sequence of DNA, useful in the biotechnology industry and criminal investigations.
Pedigree: Genetic family tree; family genealogical relationships plus expression of genotypes for certain traits; can reveal mode of inheritance for some traits and genetic disorders.
Peptide Hormones: Water soluble hormones (usually short amino acid chains) that bind to receptors and initiate a response in the target cell; present in both plants and animals.
Phagocytosis: A type of endocytosis involving large, particulate substances. (Endocytosis is the cell¹s means of obtaining extracellular material by engulfing particles within a portion of the cell membrane)
Phenotype: Observed expression of an individual¹s genotype; what a trait looks like
Phosphorus: One of the major minerals in the body. Also one of the main components in ATP production
Photomicrograph : An image taken using a microscope (light, electron, or confocal)
Photon: Packet of light energy.
Photophosphorylation: The use of light energy to phosphorylate ATP via the light-dependent reactions.
Photoreceptor: Pigment molecule(s) associated with membranes that allow animals to detect light; shape changes in pigment molecules generate action potentials to transmit sensory information to neurons; many organisms use rhodopsin as the photoreceptor pigment.
Photosynthesis: Biochemical process in primary producers (photoautotrophs) that uses the energy of sunlight to make organic molecules (organic acids and sugars) from inorganic molecules (carbon dioxide and water).
Recessive allele: An allele whose expression is masked by another allele.
Recombinant DNA: An aspect of biotechnology that allows scientists to cut a gene from a cell and insert it into another host.
Red Algae: Multicellular algae that contain red and blue pigments allowing them to run photosynthesis at greater depths.
Reflectance: Scatter and reflection of electromagnetic radiation; wavelengths that are not absorbed are reflected.
Restriction Enzyme Digest: Reaction used by restriction enzyme to cut the DNA.
Restriction Enzyme Site: The site which tells the restriction enzyme where to cut.
Photosystems I and II: Two clusters of pigment molecules that concentrate light energy at the chlorophyll a reaction center, and provide an energized electron to an electron transport chain, which drives the formation of ATP; located in thylakoid membranes of chloroplasts.
Phycobilin: Water-soluble photosynthetic pigment
Phytoplankton: Microscopic photosynthetic organisms that drift in water
Pituitary gland: A small gland below the brain that releases hormones, e.g. those that regulate growth and reproductive processes.
Placebo: Substance substituted for experimental treatment (e.g. a sugar pill instead of drug) to minimize differences between experimental and control groups; prevents bias of subjects +/or observers knowing whether they are receiving the experimental treatment.
Plasmids: These are circular piece of DNA found in bacteria. Like other DNA molecules, they code for proteins which result in the characteristics he bacteria have. They are naturally transferred betweeen bacteria during conjugation. By inserting selected pieces of DNA into a plasmid, scientists can change the characteristics of bacteria and give them the ability to make desired proteins
Plastid: A plant organelle that encapsulates photosynthetic membranes
Plate Tectonics: The theory that the earths surface is divided into separate plates that shift and change position over long periods of time.
Ploidy: Refers to the number of chromosome sets that is characteristic of an individual or species.
Poikilotherm: Animals with body temperatures that fluctuate with the temperature of the immediate environment.
Point Source Pollution: Introduction of pollutants into an ecosystem from a single source; e.g. industrial effluents and sewage piped into a river; still a source of water pollution in the U.S. but largely regulated and monitored.
Point-source Pollution: Source of pollution that involves discharge of wastes from an identifiable point, such as a smokestack or sewage treatment plant, water pollution coming from a single point, such as a sewage outflow pipe
Polyandry: A breeding unit of one female and many males.
Polygyny: A breeding unit of one male and many females.
Population: All the members of a species that live in the same geographic area.
Population Density: The abundance or number of members of a population per unit area or volume of habitat.
Population Growth:
Predictions: A forecast about what can or will occur based on the hypothesis proposed and the conditions of an experiment. Comparing the actual occurrences to the predictions made by alternative hypotheses results in support for certain hypotheses and not others.
Primary Consumers (Herbivores): Animals that eat plants and form the second trophic level.
Primary Producers (photoautotrophs): The species forming the base of a food web or the first link in a food chain. These species can produce their own food from energy sources such as the sun.
Probability: Mathematical prediction of the likelihood of an event¹s occurrence.
Prokaryote: A type of organism (bacteria and cyanobacteria) whose cells lack both a membrane-bound nucleus and other internal membrane-bound compartments (organelles).
Punnett Square: Diagram used to represent all possible genetic combinations in a cross between two individuals.
Radiation: Heat transfer between two objects in the absence of direct contact. All objects above absolute zero emit radiation and receive radiation from their surroundings.
Reaction Center: Chlorophyll a molecule located in the center of a photosystem; functions to eject an energized electron from the photosystem to the electron transport chain.
Reading Frame: The idea that DNA nucleotides are 'read' in groups of three (codons) in order for the correct sequence of amino acids to be constructed.
Question: Typically scientists investigate components of some general question like 'What causes cancer?' or 'What leads to the formation of certain types of communities?' or more specific ones such as 'How does this hormone affect blood-sugar level?'
Random Sampling: A commonly used sampling technique in which sample units are selected in such a manner that all combinations of n units under consideration have an equal chance of being selected as the sample
Receptor Protein: Membrane protein that binds with an incoming molecule (e.g. a neurotransmitter); the binding process causes shape changes in the receptor protein, which in turn may open ion transport channels through the membrane.
Restriction Enzymes: Enzymes that recognize a specific sequence of double-stranded DNA and cut the DNA at that site. Restriction enzymes are often referred to as molecular scissors.
Retina: Sheet of photoreceptors (rods and cones) within the eye; light is focused onto the retina through the lens.
Ribosome: A structure built of RNA and protein upon which mRNA ancors during protein synthesis
RNA: Ribonucleic acid, the single-stranded molecule that transfers genetic information from the DNA and assists in its translation into protein; contains uracil rather than thymine.
Rods and Cones: Rods are photoreceptors that are responsible for black and white vision, located around the edges of the retina. Cones are responsible for color vision and are concentrated toward the center of the retina.
Rough Endoplasmic Reticulum: A labyrinth of membranous sacs and tubules that extends from the nuclear membrane towards the cell membrane and is covered on its external surface with ribosomes, hence its rough appearance, functions largely in protein synthesis.
rRNA: Ribosomal RNA,makes up the ribosomes where protein synthesis takes place.
Runoff: Drainage of nutrients or other chemicals from the land into bodies of water; cause of eutrophication and examples of non-point source pollution.
Sample Size: Number of individuals used in an experimen. One performs every experiment with more than one subject to control for individual variation. The larger the sample size, the more likely that one will see the true impact of the experimental variable.
Scramble Competition: Competition in which organisms attempt to consume the resources as quickly as they can therby preventing others from acquiring it.
Search Image: A model for visual comparison, formed as part of the behavioral mechanism by which individual predators select certain prey types and ignore others, thereby optimizing their foraging efficiency.
Search Time: Time it take an animal to find a resource (essentially the opposite of encounter rate).
Secondary Metabolites: Chemicals made in a limited group of organisms (often plants) by biochemical reactions, not part of fundamental metabolism common to all organisms. Often these have biological activity,e.g. toxic to herbivores (e.g. rotenone, caffeine, nicotine).
Selective Agent:
Selective Permeability: Property of a cell membrane in which only chemicals with certain properties (typically small and uncharged, e.g. water, ammonia, gases like oxygen and carbon dioxide) pass through unimpeded.
Sex Chromosomes: Chromosomes that carry genetic information determining sex; X and Y chromosomes in humans.
101: 2
103: 1
106: 1
202: 1
204: 1
301: 2
304: 2
305: 2
306: 1
308: 1
312: 2
401: 3
402: 1
403: 1
404: 1
405: 1
407: 1
408: 2
505: 1
509: 1
510: 1
703: 1
705: 6
803: 1
806: 1
1801: 1
1802: 1
Sex-linked trait: A trait for which genetic information is located on the X chromosome; not necessarily related to sexual characters; most individuals that show sex-linked traits in their phenotype are male; e.g. hemophilia.
Sexual Reproduction: Recombination of genetic material from two individuals ('parents') to create a third individual ('offspring'); typically includes meiosis and fertilization of gametes in multicellular organisms.
Sexual Selection: Natural selection of traits that increase an individual's reproductive success.
Sham Operation: In an experiment involving surgery or invasive procedure must be performed, the sham operation is as similar as possible to the experimental procedure and allows the experimenter to control for the effect of the surgical trauma itself.
Size Distribution: The distribution of different sizes of organisms (or objects) in a population (or other group).
Small Intestine: Digestive organ beyond the stomach where digestion is completed and nutrients are absorbed to be distributed to the lymph and circulatory systems.
Smooth Endoplasmic Reticulum: Membranous sacs and tubules without ribosomes, continuous with the rough ER, functions primarily in lipid synthesis.
Solute: A chemical that dissolves in another, forming a solution
Solution: A homogenous mixture of a substance (the solute) dissolved in water (the solvent)
Solvent: A chemical in which others dissolve, forming a solution
Solvent/Solute: A chemical in which others dissolve, forming a solution
Somatic Cell: Body cell in multicellular organisms that is not involved in gamete formation.
Speciation: The process of forming new species over time; one possible consequence of evolutionary change.
Species: All the members of a type of organism that can (potentially) interbreed with one another and are reproductively isolated (i.e. cannot interbreed) with members of other species.
Species Diversity: The total number of species (unique types of organisms) in a given biotic community or in the entire world.
Species Diversity Index: A mathematical expression of the species of plants and animals that live in particular community
S-Shaped Curve: A population growth curve that levels off; also called logistic population growth which levels off as population size approaches carrying capacity.
Statistical Tests: A matematical analysis based on certain mathematical assumptions about the data that determines whether it is likely or not that the results of an experiment are chance occurrences and not the result of the application of the experimental variable.
Stomata: Pore in a plant's epidermis through which gases excahnge between the plant and the atmosphere
Stroma: The fluid matrix within the chloroplast where the light-independent reactions of photosynthesis are performed.
Subject: A subject is the individual or unit for the experiment. It can be an animal, a plant, a plot of a crop, a petri dish of bacteria, a sample of tissue from one persons liver, a point along a stream bank, etc.
Substrate: A chemical reactant that is acted upon by the active site of an enzyme and is converted into one or more chemical products.
Substrate-Level Phosphorylation: Direct transfer of a phosphate (PO4) group from an organic molecule (e.g. a sugar phosphate) to ADP resulting in ATP.
Survivorship: The fraction of a group of individuals that survive to a particular age. A survivorship curve is a graph of age-specific survival.
Symbiosis: An intimate association of members of two different species. A biological relationship of one species of organism living in or on another species.
Synapse: A space between two neurons or between a neuron and a target cell; action potentials are converted to chemical signals to travel across this intercellular space.
Supported/Not Supported: When results of an experiment are consistent with those predicted by the hypothesis, they are interpreted as supporting it; if not, they can be said to fail to support (perhaps refute) the hypothesis. No amount of data can ever prove a hypothesis.
Surface Area: Surface area is the total area of the surface of a three-dimensional object such as a cube, pyramid or sphere. Since the surface area measures two dimensions, it is measured in square units
Taxonomy: The branch of bilogy dealing with the classification of organisms.
Temperature-Pressure-Volume: This really refers to the relationship among these as defiend by the Ideal Gas Law. Search the web for many fine tutorials.
test: checking @ 11:22 am
Theory: Hypothesis or set of hypotheses for which sufficient consensus was reached based on many different types and repetitions of experiments; tested, modified, and discarded but never proven; best explanation or model of natural world at any point in time.
Thermal Neutral Zone: The temperature range over which an organism can maintain its temperature without appreciably changing its metabolic rate.
Thermogenesis: Mechanism by which an organism generates and uses heat metabolically
Thermoregulation: The ability of an organism to balance heat loss and gain with the environment, using conduction, convection, evaporation, and radiation.
Thyroid gland: Gland located in the neck that releases hormones that regulate cellular metabolism, which at the organism/physiological level is reflected as metabolic rate.
Thyroxine: Hormone manufactured in the thyroid that regulates cellular metabolism.
Transcription: Transfer of genetic information from the DNA to mRNA.
Transduction: Incorporation of new genetic information by bacteria, following infection by a virus (bacteriophage).
Transformation: Natural uptake of foreign DNA by bacteria; process utilized in biotechnology.
Translation: Assembly of a sequence of amino acids into a polypeptide according to the sequence of codons (nucleotide triplets) in the mRNA sequence.
Transmittance: The fraction of radiant energy that passes through a substance [syn: transmission]
Transpiration: The movement of water vapor from plant parts to the atomosphere through open stomata
Travel Time: Time it take to get from one foraging area to another.
tRNA: Transfer RNA, carries amino acids to the ribosome where they are attached in the correct sequence.
Trophic (ecological) Pyramid: Feeding levels within an ecosystem; represents energy flow through an ecosytem.
Tumor: Abnormal mass of cells; if benign usually poses no threat to human health, if malignant, referred to as cancerous.
Turbidity: A measure of the degree of clarity of a solution. For cloudy water, turbidity would be high; for clear water, the turbidity would be low
UV: (Ultraviolet Radiation) Portion of the electromagnetic spectrum with wavelengths shorter than 400 nm.
Vacuole: An organelle prominent and central in many plant cells (but smaller vacuoles with different functions may also be present in some animal cells) that serves to store and/or detoxify toxins and to maintain cell rigidity/shape (turgor).
Vasoconstriction: Constriction of blood vessels to restrict blood flow.
Vasodilation: Dilation of blood vessels to increase blood flow.
Vector Cloning: The process of transfering a piece of DNA from a cell of one organism into the cell of another. This is often done by plasmids.
Vesicle: A membrane-bounded sac in a cell
Villi and Microvilli: Numerous projections on the epithelial (surface) cells of the small intestine that increase the surface area of this organ, maximizing absorption of nutrients across the cell membranes.
Visible Light Spectrum: The small range of the electromagnetic spectrum that human eyes perceive as light. Ranges from about 400 to 700 nm, corresponding to blue through red light
Visual Acuity: The ability of the eye to resolve detail.
Warning Coloration: Bright colors and bold patterns that act as defense systems against predation, advertising that the colored individual is toxic.
Wavelength: The distance moved by a photon during a complete vibration; dependent on the energy of the photon; higher energy photons have shorter wavelengths.
What is Science?: Study of natural or observable world; way to learn the causes of phenomena by testing predictions based on possible explanations of how the phenomena arise; way to gain knowledge by a dynamic process of gathering and testing information.
Xanthophyll: A yellow carotenoid pigment
Xylem: Plant tissue that transports dissolved ions and water.
Absorbance: The ability to take up electromagnetic radiation by objects; different wavelengths of the visible light spectrum have different absorbances and appear as different colors.
Absorption spectrum: The particular wavelengths of light that are absorbed by objects, e.g. pigment molecules, measured by a spectrophotometer.
Accessory pigments: Pigments that expand the accessible wavelengths that can be absorbed and used in photosynthesis, e.g. carotene (absorbs between 460 and 550nm, appears red, orange, or yellow) and phycocyanin (absorbs between 550 and 640 nm, appears blue).
Acetylcholine: A neurotransmitter secreted by motor neurons.
Acetylcholinesterase: An enzyme that inactivates acetylcholine.
Acid Rain: Also called acid precipitation or acid deposition, acid rain is precipitation containing harmful amounts of nitric and sulfuric acids formed primarily by nitrogen oxides and sulfur oxides released into the atmosphere when fossil fuels are burned
Action Potential: An electrochemical change that occurs across the cell membrane of a neuron.
Action Spectrum: Rate of activity in relation to wavelength of light, e.g. photosynthesis most active in blue and red parts of the visible spectrum
Active Site: Specific location on an enzyme in which the substrate molecule(s) fit(s).
Adaptation: An inherited trait thatenables an organism to survive a particular environmentalchallenge.
Adaptive Radiation: The divergence of many new species from an ancestral species, usually a rapid process, often tied to the colonization of new environments.
Adipose Tissue: Aggregations of fat cells in animals; white adipose tissue used for energy storage; brown adipose tissue used to release heat energy.
Aerobic (cellular) respiration: A series of metabolic reactions grouped into three subpathways.
agar: an enriched gelatinous media on which various microorganisms can grow
Algal blooms: Unusually high growth and biomass of various types of simple aquatic plant-like organisms (e.g. dinoflagellates, cyanobacteria), usually attributed to excess nutrient levels (nitrogen or phosphorus), glycolysis, Krebs cycle and electron transport/oxidative phosphorylation), occurring in the cells of most organisms, to convert food molecules (e.g. sugars like glucose) into usable energy (ATP). Some of the compounds involved in respiration also provide links to other metabolic pathways, such a
Alleles: Alternate forms of a gene, reflecting differences in the DNA nucleotide sequence; often described in terms of their expression in an organism.
Alternative Hypothesis: A second hypothesis to be considered and tested simultaneously with the first.
Amino acids: The building blocks of protein; 20 different amino acids exist naturally in organisms.
Analysis: To determine whether the results of your experiment are meaningful, one performs some sort of analysis that lets one see trends or patterns in the data.
Anoxia: Depletion of dissolved oxygen levels to near zero by respiration of algae and decomposers (bacteria and fungi), often an end result of large algal blooms as the algae die and decompose.
Antibody: Protein that B cells secrete that recognizes and binds to foreign antigens, disabling them or signaling other cells to do so.
Antigen: The specific parts of molecules that elicit an immune response.
Apoptosis: Genetically programmed cell death; normal part of embryonic development in animals.
Asexual Reproduction: Reproduction by cell division without exchange of genetic material.
DNA: Deoxyribonucleic acid, the double-stranded molecule that comprises the genetic material in virtually all organisms; organized into chromosomes and stored in the nucleus in eukaryotes.
Dominant Allele: An allele that masks the expression of another allele.
Assumptions: In every experiment assumptions are made which are very basic and broad, e.g. Laws of Nature are same across time and space or events in the natural world have natural causes or specific to experiment e.g. Insects cannot see infrared.
ATP: Adenosine triphosphate, an energy carrier; formed either by substrate-level phosphorylation (a phosphate group is directly transferred from another molecule to ADP) or by oxidative phosphorylation (a free phosphate is attached to ADP by chemiosmosis).
Autosomes: Non-sex chromosomes.
Autotroph: Types of organisms that can manufacture energy rich organic molecules from inorganic compounds such as water and carbon dioxide.
Avoidance: Short or long-term strategies for avoiding extremes of heat and cold, e.g.burrowing, dormancy.
Axon: A long, thick extension of a neuron that sends messages away from the cell body of the neuron.
Base Pairs: Two bases which form a "rung of the DNA ladder." A DNA nucleotide is made of a molecule of sugar, a molecule of phosphoric acid, and a molecule called a base. The bases are the "letters" that spell out the genetic code. In DNA, the code letters are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine, respectively. In base pairing, adenine always pairs with thymine, and guanine always pairs with cytosine.
Bile: Chemical that assists in fat digestion produced by the liver and gall bladder.
Biodiversity (Biological Diversity): The total variety of living things on Earth, including genetic variation in populations and the variety of species and ecosystems.
Biogeochemical cycle: Complex global-scale recycling of materials (e.g. water, carbon, nitrogen, and phosphorus) on Earth, involving varying amounts of biological, geological, and chemical transformations.
Biomagnification: Tendency for certain chemicals to increase in concentration at higher trophic levels, usually this concentration results in expression of toxicity at these higher trophic levels; e.g. DDT.
Biomes: Distinctive types of communities and ecosystems that are recognizable over largegeographic areas.
Biotechnology: General term referring to manipulation of genetic material by humans; genetic engineering; insertion of genes into different species, alteration of gene sequences.
Camouflage: Color patterns in organisms that allow them to blend in with their environment.
Cancer: Disease in which some of the body¹s cells divide uncontrollably; many factors trigger formation of cancerous cells, ranging from viral infections to environmental damage (e.g. smoking, exposure to UV light) to genetic risk factors.
Carcinogens: Substances that cause cancer; usually carcinogens are mutagens, which is how they function to cause cancer.
carotene: an orange pigment involved in photosynthesis
Carrying capacity: The population that can be sustained indefinitely in a particular environment.
Cell: The basic unit of life, containing enzymes, membranes, genetic material and, in eukaryotes but not prokaryotes, internal membrane-bound specialized compartments called organelles.
Cell Cycle: The life cycle and activities of a single eukaryotic cell from one division to the next; includes various phases (G1, S, G2, and M) that have different functions.
Fermentation: A series of biochemical reactions required to keep glycolysis going in the absence of oxygen.
Fitness: A measure of the number of surviving offspring in the next generation; greater fitness = greater reproductive success.
Flagellum: A long whiplike appendage a cell uses for motility, composed of microtubules
Food Web: A complex of interrelated food chains in an ecological community. Also called food cycle
Gall Bladder: Organ in the human digestive system that produces and stores bile.
Cell Division: The process by which a single cell divides into two daughter cells; usually includes the division of the genetic material as well as the cytoplasm; mitosis and cytokinesis in eukaryotes, prokaryotic fission in prokaryotes.
Cell Growth: The increase in size exhibited by most cells between cell division events.
Cell Membrane: A selectively permeable fluid barrier surrounding cells and organelles.
Cell Wall: A thin membrane around the cytoplasm of a cell; controls passage of substances in and out of the cell (SEE Cell Membrane)
Chemiosmosis: A way to make ATP by moving H+ against concentration gradient across inner mitochondrial membrane during electron transport, then allowing the H+ to flow back through a channel protein. Energy inherent in H+ flow serves to add a phosphate group to ADP.
Chlorophyll a: Primary photosynthetic pigment in all organisms except bacteria; absorbs red and orange (600-700 nm) and blue and violet (400-500 nm).
Chloroplast: Eukaryotic cellular organelle that contains the machinery for operation of photosynthesis.
Chromatid (sister chromatids): Replicated chromosome that consists of two identical sequences of double-stranded DNA, joined at a constricted region called the centromere; sister chromatids divide and separate during mitosis and meiosis.
chromatography: a method for separating mixtures using liquid and stationary media. Because the components of the sample differ in solubility they separate while traveling through the stationary meduim
Chromosome: Rod-shaped structure in the eukaryotic cell nucleus consisting of a continuous molecule of double-stranded DNA wrapped with protein.
Cilium: A microscopic hairlike process extending from the surface of a cell or unicellular organism. Capable of rhythmical motion, it acts in unison with other such structures to bring about the movement of the cell or of the surrounding medium
Climate: The long-term average weather in a given area, includes temperature range and precipitation amounts.
Codominance: Expression of two different alleles in heterozygotes; e.g ABO blood type alleles.
Codon: Three-letter nucleotide sequence that codes for an amino acid.
Coevolution: Occurs when two or more species (often predators/herbivores and prey/plants) mutually influence each others evolution through natural selection.
Co-factors: Vitamins in the diet that aid enzyme function in energy metabolism.
Community (Biotic): All the populations (of individual species) living in a given area.
Compentent Cells: Cells that accept the cloning vector.
Competition: Process in which individuals or species live with one another for resources in order to survive.
Complementary Strands: The double strands of DNA come together by thehydrogen bonding of adenine on one strand and thymine on the other, cytosine on one strand and guanine on the other. Therefore, if the nucleotide sequence of one strand is known, the sequence for the other can be constructed using these rules for pairing (adenine goes with thymine; cytosine goes with guanine).
Concentration Gradient: A difference in concentration (number of molecules per volume) of a substance between two points in space, e.g. on opposite sides of a cell membrane. (See also gradient).
Gene: A sequence of DNA that specifies a sequence of amino acids that forms a particular polypeptide.
Genetic Code: The correspondence between the chemical language of mRNA and the resulting polypeptide; code is read in sets of three RNA letters (a codon, e.g. AGC > serine).
Genotype: Genetic makeup of an individual.
Germ Cells: Cells that undergo meiosis and give rise to gametes; egg (female gametes) and sperm (male gametes) in animals.
Golgi Apparatus: A system of flat, stacked membrane-bound sacs where cell secretions are sorted and packaged into vesicles for exocytosis.
Conduction: The transfer of energy (in this case heat) from one place to another directly (by contact). Heat flows down a gradient from warmer to cooler areas. The grater the difference in temperature, the faster the transfer of heat.
Conjugation: A form of gene transfer (sexual reproduction) in bacteria.
Control Group: The individuals or subjects in the control group(s) are subjected to exactly the same treatment and conditions as those in the experimental group(s)EXCEPT for the application of the experimental manipulation.
Control Variable: A control variable is any of the factors that you choose to hold constant for all groups to insure that it is not that variable producing the effect, but instead it is the experimental variable that has the effect.
Controlled Experiment: In a controlled experiment, the experimenter determines the levels or amount of the variable of interest to apply. At least two groups are involved and one group is not 'exposed' to the factor of interest.
Convection: The transfer of heat energy by mass movement of a fluid (gas or liquid). Fluids in motion (like wind) facilitate heat transfer by maintaining a high heat gradient between the solid and the new portion of fluid.
Core Body Temperature: This is the internal temperature of an animal. When you take your temperature, the thermometer is not held on the surface of your skin, it is placed inside your body (somewhere!).
Countercurrent exchange: Passage of heat from one blood vessel to another.
Courtship Display: Stereotyped, elaborate, and conspicuous behaviors that prevent mating with the wrong species and overcome aggression of the opposite sex long enough for mating to occur.
Crossing Over: The exchange of homologous chromosome segments during prophase I of meiosis.
Crypsis: Concealment. An organism that is cryptic has coloration and markings that resemble the substrate or other surroundings which help to conceal it from other organisms.
Cystic fibrosis: An autosomal recessive genetic disorder; affected individuals inherit two copies of a defective gene (one from each parent) that codes for the CFTR protein (functions to transport chloride ions across cell membranes).
Cytokinesis: The division of the cytoplasm in eukaryotic cells, following the nuclear division (mitosis or meiosis).
Cytoplasm: The jellylike fluid in which cell structures are suspended
Death rate/mortality: The rate at which death occurs in a population, e.g., # deaths/10,000 individuals in the population/year.
Decomposers: Organisms that consumes feces and dead organisms
Dendrite: Short, branched extension of a neuron that receives messages from other neurons and transmits messages toward the cell body.
Dependent Variable: The dependent variable is the variable in which you are measuring changes in response to the independent or experimental variable.
Dialysis: The separation of smaller molecules from larger molecules by selective diffusion through a semipermeable membrane
Differentiation: The process by which cells become specialized in their structure and function, by restricting expression of certain genes.
Diffusion: The movement of a substance from an area of higher concentration to an area of lower concentration
Digestion: The breakdown of food into smaller subunits so that energy can be extracted via the body¹ metabolic pathways (e.g. cellular respiration).
Diploid: Two sets of chromosomes.
Direct Competition: Competition that involves behaviors directed at other organisms to prevent their access to a resource (Contest competition).
Disruptive Coloration: A distinct coloration which delays recognition of the whole animal by attracting the attention of the observer to certain elements of the color pattern.
Dissolved Oxygen: A measure of oxygen contained in the water. Adequate dissolved oxygen is critical to most aquatic organisms and is one of the more important indicators of environmental health
Double Blind Experiment: While the subjects rarely if ever know whether they are in the control or experimental group, in a double-blind experiment the person collecting data does not know either until after data are collected to avoid bias.
Ecological Diversity: The variety of different types of ecosystems on Earth, which in turn support a wide variety of species.
Ecosystem: All of the organisms (communities) in a defineable area + the physical environment of that area. Examples - pond, forest
Ectotherm: An animal that obtains body heat primarily from its external environment.
Electron Transport: Passing of electrons (taken from some organic chemical) along a series of proteins embedded in a cell membrane, e.g. the inner mitochondrial membrane. This series of proteins is referred to as the electron transport chain (ETC).
Encounter Rate: The frequency at which a predator detects prey.
Endocrine System: Glands and cells that secrete hormones.
Endosymbiosis: Literally, a symbiotic relationship between members of two species in which the smaller symbiont lives inside the larger one. Usually used to refer to symbionts that live inside a eukaryotic cell.
Endotherm: An animal that attains most of its heat internally from its metabolism.
Enzyme Inhibitor: A chemical that prevents or slows enzyme activity, e.g. by changing its shape or blocking the active site.
Enzymes (Proteins): Macromolecules made up of a genetically-determined linear sequence of amino acids, having a specific, environmentally-sensitive 3-dimensional shape, that catalyze (speed up) very specific chemical reactions.
Epidemic: Sudden rapid spread or growth of a disease.
Essential Micronutrients: Chemicals required for metabolism that are not synthesized by the organism; must be obtained in diet; vary from species to species; e.g. 8 of the 20 amino acids needed by human.
Estuaries: Transitional coastal ecosystems where fresh water from rivers and streams meets and mixes with the salty waters of the ocean; wetlands, marshes; typically have high primary productivity and support commercial and sport fisheries.
Eukaryote: A type of organism whose cells have a membrane-bound nucleus and other internal membrane-bound compartments (organelles).
Eutrophication: Slow (thousands of yrs) natural process in lakes, ponds, and coastal waters; involves build up of sediments and nutrients (N and P) and plant/algae biomass;often decreased species diversity;cultural if accelerated by fertilizer, sewage, runoff.
Evaporation: Loss of water in the form of a vapor. Because evaporation of water requires a great deal of heat, heat is transferred from an organism to its surroundings as water evaporates from the organismís surface.
Evaporative Cooling: Heat loss by evaporation of fluid from the body's surface.
Evolution: A process of change through time in the genetically determined characteristics of organisms, at the level of populations (natural selection and genetic drift), speciation and emergence of new types of organisms.
Exocytosis: Fusion of vesicles with the cell membrane that releases cell products or wastes outside of the cell.
Exotic (introduced, non-native) Species: Species that enter a new ecosystem, often introduced accidentally or intentionally, by humans; often disrupt ecological diversity and alter ecosystem function, if exotic species have no natural predators.
Experimental Group: The individuals in the experimental group are treated to some non-zero level of the factor of interest.
Experimental Variable: The experimental variable is the item or factor you wish to test to see if it affects the subjects in the way you predict based on your hypothesis.
Feedback loop: Means of regulating the timing and output of cellular metabolism; production of certain chemicals, often enzymes, can act to turn pathways on or off.
Exponential population growth: Population growth which is rapid due to an ever-expanding base of reproductive individuals. The geometric increase of a population as it grows in an ideal, unlimited environment.
Fluid Mosaic Model: The theory that describes cell membranes as a phospholipid bilayer in which are embedded proteins with a variety of functions. This model is consistent with selective permeability, chemiosmosis, electron microscopy, etc.
Genetic Counseling: Health care profession in which counselors help families assess their risk of having children with genetic disorders, based on a variety of genetic tests and understanding of the family¹s genetic history (pedigree).
Genetic Diversity: The total variety of alleles for all genes in population, communities, and all species worldwide; important for the processes of natural selection, biotechnology and agriculture.
Glycolysis: First (and most evolutionarily ancient) series of biochemical reactions of cellular respiration in which 6-carbon sugars (e.g.glucose) are split to 3-carbon compounds with a net yield of 2 ATP; can operate without oxygen in conjunction with fermentation.
Good Genes Hypothesis: Male courtship and appearance provide information to females about the health and condition of a would-be mate but states that the benefit from mating with a robust and healthy partner lies in the acquisition of genes conducive to offspring survival.
Gradient: A gradient is the difference in a variable with distance. e.g. Temperature gradient, chemical gradient
Grana: Stacks of thylakoid membranes that contain the chlorophyll pigments.
Growth factors: Chemicals that act as signals for cells to grow and/or divide; e.g. epidermal growth factor, cyclins.
Guard Cells: One of a pair of epidermal cells that open and close stomata in plants by gaining and losing turgor pressure
Handicap Hypothesis: Females prefer the trait (e.g. long tail, bright coloration, etc.) because it is a handicap to the male and therefore acts as a reliable signal of a male's genetic quality.
Handling Time: The time it takes for an animal to capture and eat its prey.
Haploid: One set of chromosomes.
Heat Radiation: Heat transfer between two objects in the absence of direct contact. All objects above absolute zero emit radiation and receive radiation from their surroundings.
Heritability: The amount of variation for a trait that can be attributed to the genes.
Heritable Traits: Observed traits or characters that have some genetic component and thus are passed from one generation to the next from parents to offspring.
Heterozygous: Individuals who carry two different alleles for a trait.
Hierarchical Classification System: The Hierarchical order of Kingdom, Phylum, Class, Order, Family, Genus, Species.
Homeostasis: The ability of organisms to maintain a stable range of internal conditions in the face of a wider range of temperature and chemical conditions in the external environment.
Homeotherm: Animals that maintain a reasonably constant body temperature independent of the immediate environmental temperature.
Homologous Chromosomes: Pairs of chromosomes that carry genes for the same traits.
Homozygous: Individuals who carry two of the same alleles for a trait.
Hormone: Chemical messengers of the endocrine system that regulate and coordinate an organism¹s physiology, often proteins or lipids.
Human Genome Project: Multi-scientist project to map the nucleotide sequence and location of each human gene
Hypertonic: The solution on one side of a membrane where the solute concentration is greater than on the other side
Hypothalamus: Part of the forebrain that links the nervous and endocrine systems; regulates many vital functions (e.g. body temperature), responsible for maintaining homeostasis.
Hypothesis: To answer some general or specific question, one develops a hypothesis, a tentative causal explanation, based on the observations that have been made.
Hypotonic: The solution on one side of a membrane where the solute concentration is less than on the other side
Immunity: A condition of being able to resist a particular disease especially through preventing development of a pathogen or its products.
Incomplete Dominance: Heterozygous phenotype is intermediate between the two homozygous phenotypes.
Independent Assortment: Random assortment of maternal and paternal chromosome homologues during metaphase I of meiosis; results in different allele combinations in different gametes.
Independent/Manipulated/Predictor Variable: An independent variable is an experimental variable or variable of interest that the experimenter typically is able to manipulate, i.e. set the values, and serves as the predictor for the result.
Infectious disease: A disease caused by an infective agent, a parasite which may be prokaryotic or eukaryotic, unicellular or multicellular.
Insulation: A layer with a limited capacity for heat transfer, like fur.
Interpret/Draw Conclusions: One interprets or draws conclusions based on the data collected and the works of others. Interpretation leads to a statement as to whether the data support the hypothesis or not. Additionally one speculates and suggests new hypotheses.
Intrasexual Competition: Competition between the sexes
Intrinsic Rate of Increase: The difference between the birth rate and the death rate, the maximum population growth rate; population growth under ideal conditions.
Ion: An atom that has lost or gained electrons, giving it an electrical charge
Isotonic: When solute concentration is the same on both side of a membrane
J-Shaped Curve: The shape of a curve depicting exponential population growth.
K+ channel: Protein that allows potassium ions to pass through a membrane.
Krebs Cycle (Citric Acid Cycle): The stage in cellular respiration that completely metabolizes the products of glycolysis.
Law of Q10: The increase of a rate of reaction as a function of temperature. As a general rule, reaction rates double with every 10o C change in temperature.
Ligase: An enzyme that catalzes formation of covalent bonds in the DNA sugar-phosphate backbone
Light Dependent Reaction: Photosynthetic pathways that use absorbed light energy to make ATP (photophosphorylation) and NADPH.
Light Independent Reaction: Chemical reactions of photosynthesis that do not require light energy directly to transform (or fix) carbon dioxide into organic carbon compounds.
Limiting Factors: Physical or biological factors that limit the size of populations; Density-Independent (climatic factors) or Density-Dependent (predation, disease, etc.)
Lipases: Enzymes that break down lipids into fatty acid subunits.
Lipids: Organic macromolecules composed mostly of C, O, and H and not soluble in water; necessary for metabolism; many function as energy storage (fats and oils), others comprise the cell membrane, others function as receptors and hormones.
Liver: Largest organ in the human body; functions in digestion by producing bile, storing glycogen and vitamins; also important in detoxifying the blood.
Lymphatic System: A companion circulatory system to the blood that acts as a filter for infections and absorbs lipids from the digestive system.
Macronutrients: Carbohydrates, fats, and proteins obtained from the diet.
Macrophage: A very large, wandering phagocyte; an amoeboid cell that moves through tissue fibers, engulfing bacteria and dead cells by phagocytosis.
Mate Choice: The mate that is chosen based on physical attributes.
Mating Strategy: A number of different strategy use to increase the chance of ones genes being past on.
Mating System: Social organization of a breeding group, may be species-specific or vary according to conditions.
Meiosis: Cell division that halves the number of chromosome sets; part of sexual reproduction.
Metabolic Rate: The rate at which an organism's metabolism takes place.
Metabolism: The sum of an organismís biochemical reactions that acquire and use energy.
Metastasis: Cancer cells that leave the original tumor and spread the cancer, usually through the bloodstream, to new parts of the body.
Mimicry: Resemblances in physical appearance between species, often only distantly related in an evolutionary sense; often associated with defenses against predation.
Missense Mutation: A mutation that changes a codon specifying a certain amino acid into a codon specifying a certain amino acid into a codon specifying a different amino acid
Mitochondria: An organelle present in all eukaryotic cells whose main function is to carry out aerobic respiration and make ATP; surrounded by a double membrane and contains own ribosomes (involved in protein synthesis) and DNA (genetic material).
Mitosis: Cell division of a parent cell that yields two genetically identical daughter cells.
Mode Of Action: The method by which something works.
Molecule: The smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atoms; a group of like or different atoms held together by chemical forces
Monogamy: A breeding unit of one male and one female, can be lifetime but not necessarily; favored if offspring have higher survival rates when both parents provide care.
Mortality: Death of organism.
mRNA: MessengerRNA, contains the genetic message transcribed from the DNA.
Mutagens: Agents that cause mutation, any change in the DNA structure; e.g. ultraviolet light, chemicals like caffeine, x-rays; mutagens function as carcinogens.
Mutation: Any change in a gene or chromosome.
Na+ channel: Protein that allows sodium ions to pass through a membrane.
Na+/K+ Pump: A mechanism that uses energy released from splitting ATP to transport Na+ out of cells and K+ into cells.
Natural Selection: Differential survival and reproduction of organisms whose genetic traits are better adapted to the organisms particular environment. Considered the main mechanism of adaptive evolution.
Neuron: A nerve cell, consisting of a cell body, a 'sending' axon and many 'receiving'dendrites.
Neurosecretions: Release of hormones from neurons that then travel to their target cells.
Neurotransmitter: A chemical passed from one neuron to receptors on another neuron or a muscle or gland cell; alters membrane permeability, either provoking or preventing an action potential.
Niche: A species way of life; includes habitat, resource use, interactions with other species.
Nitrogen: N - Nitrogen makes up 78 percent of air by volume, and is obtained by liquefaction and fractional distillation of air. Nitrogen is colorless, odorless, and generally inert, yet when combined with other molecules is very active
Nondisjunction: Failure of one or more pairs of chromosomes to separate during meiosis.
Nonsence Mutation: A point mutation that alters a codon that encodes an amino acid to one that encodes a stop codon.
Nucleoid: The part of a prokaryotic cell where the DNA is located
Nucleolus: A structure within the nucleus where RNA nucleotides are stored
Observation: Some that is detected or measured through 5 senses (or their extensions).
Oncogene: Gene that normally triggers cell division; when overexpressed, alters the cell cycle and causes cancer.
Optimal Foraging Theory: That selection favors a strategy in which a predator utilizes prey in a manner that optimizes net energy gain per unit feeding time.
Non-Point Source Pollution: Diffuse entry or introduction of pollutants into an ecosystem from a variety of sources and locations; often difficult to monitor and control; e.g. runoff from farmland into rivers and lakes; largest remaining class of water pollution in the U.S.
Nucleotides: Building blocks of nucleic acid (such as DNA), each containing a sugar, phosphate group, and nitrogenous base (adenine - A, guanine - G, cytosine - C, thymine - T in DNA; uracil ­ U instead of thymine in RNA).
Observational Experiment: The experimenter cannot set the exact values of the experimental variable or select the subjects for each groupbecause it: is ethically unacceptable, physically impossible, includes too many variables so test by correlation and conclusions less strong.
Organelle: Compartment surrounded by one or more membranes and having a specific function(s).
Osmosis: Passive diffusion of water through a semipermeable membrane
Oxidative Phosphorylation: Formation of ATP using chemiosmosis in mitochondria.
Paradigm Shift: A paradigm is a theory of such general importance or usefulness that it shapes the way science is conducted. A paradigm shift is when a paradigm is found to be in error or no longer useful and is replaced by another.
Parasitism: A symbiotic relationship in which one member lives at the expense of the other, called the host.
Parental Investment: Parent provides time, energy, and resources to survival of its offspring.
Pathogen: A parasite that causes disease in the host.
PCR: Polymerase Chain Reaction; technique that allows the replication of millions of copies of a small sequence of DNA, useful in the biotechnology industry and criminal investigations.
Pedigree: Genetic family tree; family genealogical relationships plus expression of genotypes for certain traits; can reveal mode of inheritance for some traits and genetic disorders.
Peptide Hormones: Water soluble hormones (usually short amino acid chains) that bind to receptors and initiate a response in the target cell; present in both plants and animals.
Phagocytosis: A type of endocytosis involving large, particulate substances. (Endocytosis is the cell¹s means of obtaining extracellular material by engulfing particles within a portion of the cell membrane)
Phenotype: Observed expression of an individual¹s genotype; what a trait looks like
Phosphorus: One of the major minerals in the body. Also one of the main components in ATP production
Photomicrograph : An image taken using a microscope (light, electron, or confocal)
Photon: Packet of light energy.
Photophosphorylation: The use of light energy to phosphorylate ATP via the light-dependent reactions.
Photoreceptor: Pigment molecule(s) associated with membranes that allow animals to detect light; shape changes in pigment molecules generate action potentials to transmit sensory information to neurons; many organisms use rhodopsin as the photoreceptor pigment.
Photosynthesis: Biochemical process in primary producers (photoautotrophs) that uses the energy of sunlight to make organic molecules (organic acids and sugars) from inorganic molecules (carbon dioxide and water).
Recessive allele: An allele whose expression is masked by another allele.
Recombinant DNA: An aspect of biotechnology that allows scientists to cut a gene from a cell and insert it into another host.
Red Algae: Multicellular algae that contain red and blue pigments allowing them to run photosynthesis at greater depths.
Reflectance: Scatter and reflection of electromagnetic radiation; wavelengths that are not absorbed are reflected.
Restriction Enzyme Digest: Reaction used by restriction enzyme to cut the DNA.
Restriction Enzyme Site: The site which tells the restriction enzyme where to cut.
Photosystems I and II: Two clusters of pigment molecules that concentrate light energy at the chlorophyll a reaction center, and provide an energized electron to an electron transport chain, which drives the formation of ATP; located in thylakoid membranes of chloroplasts.
Phycobilin: Water-soluble photosynthetic pigment
Phytoplankton: Microscopic photosynthetic organisms that drift in water
Pituitary gland: A small gland below the brain that releases hormones, e.g. those that regulate growth and reproductive processes.
Placebo: Substance substituted for experimental treatment (e.g. a sugar pill instead of drug) to minimize differences between experimental and control groups; prevents bias of subjects +/or observers knowing whether they are receiving the experimental treatment.
Plasmids: These are circular piece of DNA found in bacteria. Like other DNA molecules, they code for proteins which result in the characteristics he bacteria have. They are naturally transferred betweeen bacteria during conjugation. By inserting selected pieces of DNA into a plasmid, scientists can change the characteristics of bacteria and give them the ability to make desired proteins
Plastid: A plant organelle that encapsulates photosynthetic membranes
Plate Tectonics: The theory that the earths surface is divided into separate plates that shift and change position over long periods of time.
Ploidy: Refers to the number of chromosome sets that is characteristic of an individual or species.
Poikilotherm: Animals with body temperatures that fluctuate with the temperature of the immediate environment.
Point Source Pollution: Introduction of pollutants into an ecosystem from a single source; e.g. industrial effluents and sewage piped into a river; still a source of water pollution in the U.S. but largely regulated and monitored.
Point-source Pollution: Source of pollution that involves discharge of wastes from an identifiable point, such as a smokestack or sewage treatment plant, water pollution coming from a single point, such as a sewage outflow pipe
Polyandry: A breeding unit of one female and many males.
Polygyny: A breeding unit of one male and many females.
Population: All the members of a species that live in the same geographic area.
Population Density: The abundance or number of members of a population per unit area or volume of habitat.
Population Growth:
Predictions: A forecast about what can or will occur based on the hypothesis proposed and the conditions of an experiment. Comparing the actual occurrences to the predictions made by alternative hypotheses results in support for certain hypotheses and not others.
Primary Consumers (Herbivores): Animals that eat plants and form the second trophic level.
Primary Producers (photoautotrophs): The species forming the base of a food web or the first link in a food chain. These species can produce their own food from energy sources such as the sun.
Probability: Mathematical prediction of the likelihood of an event¹s occurrence.
Prokaryote: A type of organism (bacteria and cyanobacteria) whose cells lack both a membrane-bound nucleus and other internal membrane-bound compartments (organelles).
Punnett Square: Diagram used to represent all possible genetic combinations in a cross between two individuals.
Radiation: Heat transfer between two objects in the absence of direct contact. All objects above absolute zero emit radiation and receive radiation from their surroundings.
Reaction Center: Chlorophyll a molecule located in the center of a photosystem; functions to eject an energized electron from the photosystem to the electron transport chain.
Reading Frame: The idea that DNA nucleotides are 'read' in groups of three (codons) in order for the correct sequence of amino acids to be constructed.
Question: Typically scientists investigate components of some general question like 'What causes cancer?' or 'What leads to the formation of certain types of communities?' or more specific ones such as 'How does this hormone affect blood-sugar level?'
Random Sampling: A commonly used sampling technique in which sample units are selected in such a manner that all combinations of n units under consideration have an equal chance of being selected as the sample
Receptor Protein: Membrane protein that binds with an incoming molecule (e.g. a neurotransmitter); the binding process causes shape changes in the receptor protein, which in turn may open ion transport channels through the membrane.
Restriction Enzymes: Enzymes that recognize a specific sequence of double-stranded DNA and cut the DNA at that site. Restriction enzymes are often referred to as molecular scissors.
Retina: Sheet of photoreceptors (rods and cones) within the eye; light is focused onto the retina through the lens.
Ribosome: A structure built of RNA and protein upon which mRNA ancors during protein synthesis
RNA: Ribonucleic acid, the single-stranded molecule that transfers genetic information from the DNA and assists in its translation into protein; contains uracil rather than thymine.
Rods and Cones: Rods are photoreceptors that are responsible for black and white vision, located around the edges of the retina. Cones are responsible for color vision and are concentrated toward the center of the retina.
Rough Endoplasmic Reticulum: A labyrinth of membranous sacs and tubules that extends from the nuclear membrane towards the cell membrane and is covered on its external surface with ribosomes, hence its rough appearance, functions largely in protein synthesis.
rRNA: Ribosomal RNA,makes up the ribosomes where protein synthesis takes place.
Runoff: Drainage of nutrients or other chemicals from the land into bodies of water; cause of eutrophication and examples of non-point source pollution.
Sample Size: Number of individuals used in an experimen. One performs every experiment with more than one subject to control for individual variation. The larger the sample size, the more likely that one will see the true impact of the experimental variable.
Scramble Competition: Competition in which organisms attempt to consume the resources as quickly as they can therby preventing others from acquiring it.
Search Image: A model for visual comparison, formed as part of the behavioral mechanism by which individual predators select certain prey types and ignore others, thereby optimizing their foraging efficiency.
Search Time: Time it take an animal to find a resource (essentially the opposite of encounter rate).
Secondary Metabolites: Chemicals made in a limited group of organisms (often plants) by biochemical reactions, not part of fundamental metabolism common to all organisms. Often these have biological activity,e.g. toxic to herbivores (e.g. rotenone, caffeine, nicotine).
Selective Agent:
Selective Permeability: Property of a cell membrane in which only chemicals with certain properties (typically small and uncharged, e.g. water, ammonia, gases like oxygen and carbon dioxide) pass through unimpeded.
Sex Chromosomes: Chromosomes that carry genetic information determining sex; X and Y chromosomes in humans.
101: 2
103: 1
106: 1
202: 1
204: 1
301: 2
304: 2
305: 2
306: 1
308: 1
312: 2
401: 3
402: 1
403: 1
404: 1
405: 1
407: 1
408: 2
505: 1
509: 1
510: 1
703: 1
705: 6
803: 1
806: 1
1801: 1
1802: 1
Sex-linked trait: A trait for which genetic information is located on the X chromosome; not necessarily related to sexual characters; most individuals that show sex-linked traits in their phenotype are male; e.g. hemophilia.
Sexual Reproduction: Recombination of genetic material from two individuals ('parents') to create a third individual ('offspring'); typically includes meiosis and fertilization of gametes in multicellular organisms.
Sexual Selection: Natural selection of traits that increase an individual's reproductive success.
Sham Operation: In an experiment involving surgery or invasive procedure must be performed, the sham operation is as similar as possible to the experimental procedure and allows the experimenter to control for the effect of the surgical trauma itself.
Size Distribution: The distribution of different sizes of organisms (or objects) in a population (or other group).
Small Intestine: Digestive organ beyond the stomach where digestion is completed and nutrients are absorbed to be distributed to the lymph and circulatory systems.
Smooth Endoplasmic Reticulum: Membranous sacs and tubules without ribosomes, continuous with the rough ER, functions primarily in lipid synthesis.
Solute: A chemical that dissolves in another, forming a solution
Solution: A homogenous mixture of a substance (the solute) dissolved in water (the solvent)
Solvent: A chemical in which others dissolve, forming a solution
Solvent/Solute: A chemical in which others dissolve, forming a solution
Somatic Cell: Body cell in multicellular organisms that is not involved in gamete formation.
Speciation: The process of forming new species over time; one possible consequence of evolutionary change.
Species: All the members of a type of organism that can (potentially) interbreed with one another and are reproductively isolated (i.e. cannot interbreed) with members of other species.
Species Diversity: The total number of species (unique types of organisms) in a given biotic community or in the entire world.
Species Diversity Index: A mathematical expression of the species of plants and animals that live in particular community
S-Shaped Curve: A population growth curve that levels off; also called logistic population growth which levels off as population size approaches carrying capacity.
Statistical Tests: A matematical analysis based on certain mathematical assumptions about the data that determines whether it is likely or not that the results of an experiment are chance occurrences and not the result of the application of the experimental variable.
Stomata: Pore in a plant's epidermis through which gases excahnge between the plant and the atmosphere
Stroma: The fluid matrix within the chloroplast where the light-independent reactions of photosynthesis are performed.
Subject: A subject is the individual or unit for the experiment. It can be an animal, a plant, a plot of a crop, a petri dish of bacteria, a sample of tissue from one persons liver, a point along a stream bank, etc.
Substrate: A chemical reactant that is acted upon by the active site of an enzyme and is converted into one or more chemical products.
Substrate-Level Phosphorylation: Direct transfer of a phosphate (PO4) group from an organic molecule (e.g. a sugar phosphate) to ADP resulting in ATP.
Survivorship: The fraction of a group of individuals that survive to a particular age. A survivorship curve is a graph of age-specific survival.
Symbiosis: An intimate association of members of two different species. A biological relationship of one species of organism living in or on another species.
Synapse: A space between two neurons or between a neuron and a target cell; action potentials are converted to chemical signals to travel across this intercellular space.
Supported/Not Supported: When results of an experiment are consistent with those predicted by the hypothesis, they are interpreted as supporting it; if not, they can be said to fail to support (perhaps refute) the hypothesis. No amount of data can ever prove a hypothesis.
Surface Area: Surface area is the total area of the surface of a three-dimensional object such as a cube, pyramid or sphere. Since the surface area measures two dimensions, it is measured in square units
Taxonomy: The branch of bilogy dealing with the classification of organisms.
Temperature-Pressure-Volume: This really refers to the relationship among these as defiend by the Ideal Gas Law. Search the web for many fine tutorials.
test: checking @ 11:22 am
Theory: Hypothesis or set of hypotheses for which sufficient consensus was reached based on many different types and repetitions of experiments; tested, modified, and discarded but never proven; best explanation or model of natural world at any point in time.
Thermal Neutral Zone: The temperature range over which an organism can maintain its temperature without appreciably changing its metabolic rate.
Thermogenesis: Mechanism by which an organism generates and uses heat metabolically
Thermoregulation: The ability of an organism to balance heat loss and gain with the environment, using conduction, convection, evaporation, and radiation.
Thyroid gland: Gland located in the neck that releases hormones that regulate cellular metabolism, which at the organism/physiological level is reflected as metabolic rate.
Thyroxine: Hormone manufactured in the thyroid that regulates cellular metabolism.
Transcription: Transfer of genetic information from the DNA to mRNA.
Transduction: Incorporation of new genetic information by bacteria, following infection by a virus (bacteriophage).
Transformation: Natural uptake of foreign DNA by bacteria; process utilized in biotechnology.
Translation: Assembly of a sequence of amino acids into a polypeptide according to the sequence of codons (nucleotide triplets) in the mRNA sequence.
Transmittance: The fraction of radiant energy that passes through a substance [syn: transmission]
Transpiration: The movement of water vapor from plant parts to the atomosphere through open stomata
Travel Time: Time it take to get from one foraging area to another.
tRNA: Transfer RNA, carries amino acids to the ribosome where they are attached in the correct sequence.
Trophic (ecological) Pyramid: Feeding levels within an ecosystem; represents energy flow through an ecosytem.
Tumor: Abnormal mass of cells; if benign usually poses no threat to human health, if malignant, referred to as cancerous.
Turbidity: A measure of the degree of clarity of a solution. For cloudy water, turbidity would be high; for clear water, the turbidity would be low
UV: (Ultraviolet Radiation) Portion of the electromagnetic spectrum with wavelengths shorter than 400 nm.
Vacuole: An organelle prominent and central in many plant cells (but smaller vacuoles with different functions may also be present in some animal cells) that serves to store and/or detoxify toxins and to maintain cell rigidity/shape (turgor).
Vasoconstriction: Constriction of blood vessels to restrict blood flow.
Vasodilation: Dilation of blood vessels to increase blood flow.
Vector Cloning: The process of transfering a piece of DNA from a cell of one organism into the cell of another. This is often done by plasmids.
Vesicle: A membrane-bounded sac in a cell
Villi and Microvilli: Numerous projections on the epithelial (surface) cells of the small intestine that increase the surface area of this organ, maximizing absorption of nutrients across the cell membranes.
Visible Light Spectrum: The small range of the electromagnetic spectrum that human eyes perceive as light. Ranges from about 400 to 700 nm, corresponding to blue through red light
Visual Acuity: The ability of the eye to resolve detail.
Warning Coloration: Bright colors and bold patterns that act as defense systems against predation, advertising that the colored individual is toxic.
Wavelength: The distance moved by a photon during a complete vibration; dependent on the energy of the photon; higher energy photons have shorter wavelengths.
What is Science?: Study of natural or observable world; way to learn the causes of phenomena by testing predictions based on possible explanations of how the phenomena arise; way to gain knowledge by a dynamic process of gathering and testing information.
Xanthophyll: A yellow carotenoid pigment
Xylem: Plant tissue that transports dissolved ions and water.