Weaver Bio Chapter 2
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47 terms
Terms | Definitions |
|---|---|
 atom | the basic unit of matter |
| nucleus | the center of an atom, made up of protons and neutron |
| proton | the positively charged particle in an atom |
| neutron | the particle of an atom that has no charge |
| electron | the negatively charged particle in an atom |
| element | a pure substance that contains ony one kind of atom |
| compound | a substance that is made of more than one kind of element, combimed in sepcific proportions |
| atomic number | the number of protons in an atom |
| mass number | the total mass of the protons and neutrons in a particular atom |
| isotopes | two atoms of the same element with different mass numbers (same number of protons, different number of neutrons) |
| ionic bond | a bond that is formed when one atom gives electrons to another atom |
| covalent bond | a bond that is formed when atoms share electrons |
| atomic mass | the average mass of all isotopes of a given element |
| valence electron | an electron in an atom's outer energy level, where it can take part in a reaction with other atoms |
| ion | an atom or molecule that has a charge because it has gained or lost electrons |
| hydrogen bond | a weak attraction between a hydrogen atom and another atom; the way water molecules bond |
| molecule | the particle created when atoms bond together, with either similar or different kinds of atoms |
| polar | an arrangement of a molecule where one side has a positive charge and the other has a negative charge |
| cohesion | the attraction between molecules of the same substance |
| adhesion | the attraction between molecules of different substances |
| mixture | a material made of two or more substances that are not chemically combined |
| solution | a material made of at least one substance that has dissolved another, so that all the components are equally distributed |
| solute | the material that is dissolved in a solution |
| solvent | the material that dissolves another substance in a solution |
| pH | a measure of how acidic or basic a substance is (the concentration of H+ ions) |
| acid | a substance with a pH lower than 7; forms H+ ions in a solution |
| base | a substance with a pH higher than 7; forms OH- ions in a solution |
| buffers | weak acids or bases that react with strong acids or bases to prevent a sudden change in pH |
| monomer | a small compound that joins with others to make a polymer |
| polymer | a macromolecule formed by joining many monomers |
| carbohydrate | compounds made of carbon, hydrogen, and oxygen, usually in the ratio of 1:2:1 |
| monosaccharide | a simple suger made of one molecule |
| starch | a substance that forms when sugars join in long chains |
| polysaccharide | a macromolecule that stores sugars in the body; formed by joining many monosaccharides |
| lipid | an energy-storing family of molecules made mostly of carbon and hydrogen, and which are not soluble in water; "fats" |
| nucleic acid | macromolecules made of nucleotides; 2 kinds: DNA and RNA |
| nucleotide | the building block of a nucleic acid |
| protein | macromolecules made of combinations of amino acids |
| amino acid | the building block of a protein |
| chemical reaction | a process that changes one set of chemicals into another |
| reactants | the chemicals that enter an chemical reaction |
| products | the chemicals that result from a chemical reaction |
| activation energy | the energy needed to get a reaction started |
| catalyst | a substance that speeds up the rate of a chemical reaction by lowering the activation energy |
| enzyme | a protein that acts as a catalyst |
| substrate | the reactants in a chemical reaction that uses an enzyme as a catalyst |
| van der Waals forces | the weak attraction between the oppositely charged regions of nearby molecules |
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