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Biology Chapter 2
9th grade BJU Biology Chapter 2
Term | Definition |
---|---|
matter | the physical stuff that makes up the universe |
atom | the basic building blocks of matter |
element | pure substances made of only one kind of atom |
energy | the immaterial stuff that gets things done - the ability to work |
temperature | relative hotness or coldness |
enthropy | the tendency of energy to disperse and become less available to do work |
physical change | changes that don't change a matter's identity |
chemical change | matter changing in a way that completely changes its identity |
bond | stored chemical energy that holds two atoms together |
compound | a pure substance made of two or more element chemically combined |
molecule | the smallest part of a covalent compound |
dissolving | the process by which one substance is broken up into smaller pieces by another substance |
acid | a substance that dissolves in water to form hydrogen ions |
base | a substance that dissolves in water to form hydroxide ions |
diffusion | the process by which particles in a solution are evenly distributed throughout the solvent by Brownian motion |
reactant | a substance that is present before a chemical reaction and takes part in it |
product | the substances formed during a chemical reaction |
catalyst | a substance that changes the rate of a chemical reaction, not affected by the reaction |
enzyme | a naturally occurring catalyst, usually a protein |
inhibitor | a substance that bins an enzyme and reduces its activity |
polar | quality of molecules having an uneven distribution of electrical charge |
cohesion | the attraction between like particles within polar substances |
adhesion | the attraction of particles in one substance for particles in a different substance |
organic compound | a covalently bonded compound containing the element carbon |
carbohydrate | an organic compound comprised of the elements carbon, hydrogen, and oxygen; includes sugars, starch, and cellulose |
sugar | a class of simple organic compounds important in living things as a source of both energy and structure |
lipid | a class of non-polar organic compounds that are insoluble in water |
amino acids | a class of organic compounds that serve as the building blocks of proteins |
nucleotide | a class of organic compounds that serve as the basic building blocks for the information storage molecules DNA and RNA |