First AP Biology Test!
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116 terms
Terms | Definitions |
|---|---|
 Biology | Study of living organisms and how they have evolved. |
| Deductive | Applies general principles to predict specific results. |
| Inductive | Uses specific observations to construct general scientific principles. |
| Hypothesis | An educated guess. |
| Variables | Factors that influence the processes. |
| Theory | Is a proposed explanation for some natural phenomenon, often based on some general principle. |
| Artificial selection | A process to produce certain characteristics. |
| Natural selection | Nature's process in playing the breeder's role in selecting the next generation. |
| Heredity | All organisms on earth possess a genetic system that is based on the replication of a long, complex molecule called DNA. This mechanism allows for adaption and evolution over time, also distinguishing characteristics of living things. |
| Matter | Any substance in the universe that has mass and occupies space. |
| Atoms | Extremely small particles. |
| Niels Bohr | Proposed that every atom possesses an orbiting cloud of tiny subatomic particles called electrons. |
| Atomic number | Number of protons |
| Mass | Amount of substance |
| Weight | Force gravity exerts on a substance |
| Daltons | The mass of atoms and subatomic particles |
| Element | Is any substance that cannot be broken down to any other substance by ordinary chemical means. |
| Isotopes | Atoms of an element that possess different numbers of neutrons. |
| Radioactive isotopes | Isotopes that emit a significant amount of energy and decay. |
| Half-life | The time it takes for one half of the atoms in a sample to decay. |
| Ions | Atoms in which the number of electrons does not equal the number of protons. |
| Cation | An atom that has more protons than electrons has a net positive charge. |
| Anion | An atom that has fewer protons than electrons carries a net negative charge. |
| Orbital | The area around the nucleus where the electron is most likely to be found. |
| Potential energy | The ability to work. |
| Oxidation | Loss of an electron |
| Reduction | The gain of an electron |
| Demitri Mendeleev | A Russian chemist that arranged the known elements in a table according to their atomic mass. |
| Valence electrons | Are the basis for the differing chemical properties of the elements. |
| Inert (non-reactive) | Electrons possess eight electrons in their outer energy level. |
| Octet rule or Rule of Eights | Atoms tend to establish completely full outer energy levels. |
| Molecule | A group of atoms held together by energy in a stable association. |
| Compound | When a molecule contains atoms of more than one element. |
| Ionic bonds | Form when atoms with opposite charges attract. |
| Ionic compound | NaCl |
| Covalent bonds | Form when two atoms share one or more pairs of valence electrons. |
| Double bonds | Allows two atoms to share two pairs of electrons, stronger than single bonds. |
| Single bonds | Only one electron shared. |
| Triple bonds | Link the two nitrogen atoms of nitrogen gas molecules, strongest covalent bond. |
| Chemical reactions | The formation and breaking of chemical bonds. |
| Reactants | The original molecules before the reaction starts. |
| Product | The molecules resulting from a chemical reaction. |
| Water | Exists as a liquid at the relatively low temperatures that prevail on the earth's surface. |
| Electronegativity | Both the oxygen and hydrogen atoms attract the electrons they share in the covalent bonds of a water molecule. |
| Polar molecules | Molecules that exhibit charge separation. |
| Hydrogen bonds | Interactions that involve hydrogen atoms. |
| Cohesion | When the other molecules are also water. |
| Adhesion | When the other molecules are of a different substance. |
| Surface tension | The cohesion of liquid water. |
| Specific heat | The amount of heat that must be absorbed or lost by 1 gram of a substance to change its temperature by 1 degree Celsius.Heat of vaporization. |
| Hydration shell | Every time a sucrose molecule dissociates or breaks away from the crystal, water molecules surround it in a cloud, preventing it from associating with other sucrose molecules. |
| Hydrophobic | Polar molecules that shrink from contact with water. |
| Hydrophilic | Polar molecules that readily form hydrogen bonds with water. |
| Hydrophobic exclusion | The tendency of non polar molecules to aggregate in water. |
| Hydroxide ion | The rest of the dissociated water molecule, which has retained the shared electron from the covalent bond, is negatively charged. |
| Mole | The weight in grams that corresponds to the summed atomic masses of all atoms in a molecule. |
| pH scale | A more convenient way to express the hydrogen ion concentration of a solution. |
| Logarithmic | A difference of 1 on the scale represents a tenfold change in hydrogen ion concentration. |
| Acid | Any substance that dissociates in water to increase the concentration of H+ ions. |
| Base | Any substance that combines with H+ ions when dissolved in water. |
| Buffer | Is a substance that acts as a reservoir for hydrogen ions, donating them to the solution when their concentration falls and taking them from the solution when their concentration rises. |
| Organic molecules | Chemical compounds that contain carbon. |
| Hydrocarbons | Organic molecules consisting of only carbon and hydrogen. |
| Functional groups | Molecules can be thought of as a C-H core to which specific groups are attached. |
| Hydroxyl group | Is a substance that acts as a reservoir for hydrogen ions, donating them to the solution when their concentration falls and taking them from the solution when their concentration rises. |
| Macromolecules | Large, complex assemblies |
| Polymers | Molecules built by linking together a large number of small similar chemical subunits. |
| Dehydration synthesis | A condensation reaction that form a covalent bond between two subunit molecules. |
| Hydrolysis | Cells disassemble macromolecules into their constituent subunits by performing reactions that are essentially the reverse of dehydration- a water molecule is added instead of removed. |
| Carbohydrates | Are a loosely defined group of molecules that contain carbon, hydrogen, and oxygen in the molar ratio 1:2:1. |
| Empirical Formula | Lists the atoms in the molecule with subscripts to indicate how many there are of each. |
| Monosaccharides | The simplest of the carbohydrates. |
| Disaccharides | Two monosaccharides joined by a covalent bond. |
| Polysaccharides | Are macromolecules made up of monosaccharide subunits. |
| Isomers | Sugars that are an alternative form of glucose. |
| Enzymes | The agents that carry out most of catalysis in living organisms are proteins. |
| Substrates | The molecules that will undergo the reaction. |
| Carbonic Anhydrase | An enzyme within the cytoplasm |
| Active sites | Pockets or clefts on the surface of a globular protein. |
| Enzyme-substrate complex | Substrates bind to the enzyme at these active sites. |
| Multienzyme complexes | Often in cells the several enzymes catalyzing the different steps of a sequence of reactions are loosely associated with one another in non-covalently bonded assemblies. |
| Temperature Optimum | The rate of enzyme- catalyzed reaction also increases with temperature, but only up to a point. |
| pH Optimum | Ranges from 6-8. |
| Inhibitor | A substance that binds to an enzyme and decreases activity |
| Competitive Inhibitors | Compete with the substrate for the same bind. |
| Noncompetitive inhibitors | Bind to the enzyme in a location other than the active site, changing the shape of the enzyme and making it unable to bind to the substrate. |
| Allosteric site | Most noncompetitive inhibitors bind to a specific portion of the enzyme. |
| Allosteric inhibitor | A substance that binds to an allosteric site and reduces enzyme activity. |
| Activators | Bind to allosteric sites and keep the enzymes in their active configurations, thereby increasing enzyme activity. |
| Cofactors | Enzyme function is often assisted by additional chemical components. |
| Coenzymes | When the cofactor is a non-protein organic molecule. |
| Nicotinamide adenine dinucleotide | One of the most important coenzymes is the hydrogen acceptor.. |
| Contractile Proteins | Also play key roles in the cell's cytoskeleton and in moving materials within cells. |
| Intercellular messengers | Small proteins called hormones in animals serve as.. |
| Amino acid | Is a molecule containing an amino group, carboxyl group, and a hydrogen atom, all bonded to a central carbon atom. |
| Peptide bond | A covalent bond that links two amino acids. |
| Protein | Is composed of one or more long chains, or polypeptides. |
| Polypeptides | Composed of amino acids linked together by peptide bonds. |
| Domain | Each exon-encoded section of a protein, typically 100 to 200 amino acids long, folds into a structurally independent functional unit. |
| Chaperonins | Further study revealed that normal cells contain special proteins. |
| Denaturation | If a protein's environment is altered, the protein may change its shape or even unfold. |
| Dissociation | A small protein may spontaneously refold into it's natural shape, driven by the interactions between its nonpolar amino acids and water. |
| DNA | Encodes the information used to assemble proteins is similar to the way in which the letters on a page encode information. |
| Nucleotides | Nucleic acids are long polymers of repeating subunits. |
| Nucleic acid | Is simply a chain of five-carbon sugars linked together by phosphodi-ester bonds with an organic base protruding from each sugar. |
| Purines | Are large, double-ring molecules found in both DNA and RNA. |
| Pyrimidine | Are smaller, single-ring molecules. |
| Double helix | Such a winding about one another, as in DNA. |
| Fats | Consist of a glycerol molecule to which is attached three fatty acids, one to each carbon of the glycerol backbone. |
| Triglyceride | Because it contains three fatty acids, a fat molecule. |
| Saturated | If all of the internal carbon atoms in the fatty acid chains are bonded to at least two hydrogen atoms. |
| Unsaturated | If a fatty acid has double bonds between one or more pairs of successive carbon atoms |
| Polyunsaturated | If a given fatty acid has more then one double bond. |
| Terpenes | Are long-chain lipids that are components of many biologically important pigments. |
| Steroids | Found in membranes, composed of four carbon rings. |
| Prostaglandins | Group of 20 lipids that are modified fatty acids. |
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