| A | B |
|---|
| atom | basic unit of matter |
| nucleus | the center of the atom which contains the protons and neutrons; in cells, structure that contains the cell's genetic material (DNA) and controls the cell's activities |
| electron | a negatively charged particle (-) with 1/ 1840 the mass of a proton. |
| element | a pure substance that consists entirely of one type of atom |
| isotopes | atoms of the same element that difffer in the number of neutrons they contain are known |
| compound | a substance formed by the chemical combination of two or more elements in definate proportions |
| ionic bond | formed when one or more electrons are transferred from one atom to another |
| ions | positively and negatively charged atoms |
| covalent bond | formed when electrons are shared between atoms |
| molecule | the smallest unit of most compounds |
| van der Waals forces | a slight attraction that develops between the oppositely charged regions of nearby molecules |
| cohesion | an attraction beween molecules of the same substance. |
| adhesion | attraction between molecules of different substances |
| mixture | a material composed of two or more elements or compounds that are physically mixed together but not chemically combined |
| solution | mixture of two or more substances in which the molecules of the substances are evenly distributed |
| solute | the substance that is dissolved |
| solvent | the substance in which the solute dissolves |
| suspensions | mixture of water and nondissolved materials |
| pH scale | that indicates the concentration of H+ ions in solution |
| acid | any compound that forms H+ ions in solution |
| base | a compound that produces hydroxide isons(OH- ions) in solution |
| buffers | weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH. |
| monomer | small unit that can join together with other small units to form polymers |
| polymer | large compound formed from combinations of many monomers |
| carbohydrates | compounds made up of carbon, hydrogen, and oxygen atoms, usually in a ration of 1 : 2 : 1 |
| monosaccharides | single sugar molecules |
| polysaccharides | the large macromolecules formed from monosaccharides |
| lipids | large varied group of biological molecules that are generally not soluble in water |
| nucleic acids | mocromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosporus. |
| nucleotides | individual monomers that consist of three parts: a 5 carbon sugar, a phospate group and a nitrogenous base. |
| ribonucleic acid (RNA) | Nucleic acid that contains sugar ribose |
| deoxyriboncleic acid (DNA) | Nucleic acid that contains the sugar deoxyribose |
| proteins | macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen |
| amino acids | proteins that are polymers of molecules. |
| chemical reaction | a process that changes, or transforms one set of chemicals into another. |
| reactants | the elements or compounds that enter into a chemical reaction |
| products | the elements or compounds produced by a chemical reaction |
| activation energy | the energy that is needed to get a reaction started. |
| catalyst | a substance that speeds up the rate of a chemical reaction. |
| enzymes | proteins that act as biological catalysts |
| substrates | the reactants of enzyme- catalyzed reactions |
