biology

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Across
  1. 1. A substance that is present before a chemical reaction and takes part in it, usually shown on the left-hand side of a chemical equation.
  2. 3. The building block of matter; the smallest possible particle of an element.
  3. 4. An attraction between two atoms as a result of sharing or transferring valence electrons.
  4. 6. A change in a substance that results in one or more new substances being formed that have different physical and chemical properties than those of the original substance.
  5. 7. The process by which particles in solution are evenly distributed throughout the solvent by Brownian motion.
  6. 9. The process by which one substance, the solute, is broken up into smaller pieces by and distributed within a second substance, the solvent.
  7. 10. A substance that can produce hydroxide ions (OH-) or accept hydrogen ions (H+) in solution.
  8. 13. A class of nonpolar organic compounds that are insoluble in water and are used for energy storage and cell membranes in living things.
  9. 14. The substances formed during a chemical reaction, usually indicated on the right-hand side of the chemical equation.
  10. 15. The tendency of energy to disperse and become less available to do work.
  11. 16. A change in a substance that does not change to identity of the substance (e.g., a change of form or state).
  12. 21. A measurement of the average speed of the particles within a substance.
  13. 23. An organic compound comprised of the elements carbon, hydrogen, and oxygen; includes sugars, starch, and cellulose.
  14. 24. A naturally occurring catalyst, usually a protein.
  15. 26. The smallest particle of a covalently bonded compound.
  16. 27. A class of organic compounds that serve as the building blocks of proteins.
Down
  1. 2. A pure substance made from two or more elements that are chemically combined.
  2. 3. The attraction of particles in one substance for particles in a different substance.
  3. 5. A substance that binds to an enzyme and reduces its activity, thus slowing a chemical reaction that the enzyme catalyzes.
  4. 8. The attraction between like particles within polar substances.
  5. 11. A substance that can produce hydrogen ions (H+) in solution.
  6. 12. A substance that changes the rate of a chemical reaction but is not itself used up or affected by the reaction.
  7. 15. A pure substance made of only one kind of atom.
  8. 17. A class of simple organic compounds important in living things as a source of both energy and structure.
  9. 18. The ability to do work. Especially in biology, the driver of the physical and chemical processes necessary for life.
  10. 19. Quality of molecules having an uneven distribution of electrical charge, resulting in some regions of a molecule having negative charge while others are positive.
  11. 20. A covalently bonded compound containing the element carbon.
  12. 22. The physical stuff that makes up the universe. Anything that occupies space and has mass.
  13. 25. A class of organic compounds that serve as the building blocks for the information storage molecules DNA and RNA.