Couldn't confirm presence of Flash 7 or higher because JavaScript was disabled.
We highly recommend that you install Flash 7 or higher and that you enable JavaScript.
Get Flash ---
I really do have Flash installed.
What follows is a plain HTML version of the puzzle.
Chapter 2 - The Chemistry of Life
Across
1. bond formed by the sharing of electrons between atoms
6. attraction between molecules of the same substance
8. macromolecule made mainly from carbon and hydrogen atoms; includes fats, oils, and waxes
9. smallest unit of most compounds
10. basic unit of matter
11. substance that speeds up the rate of a chemical reaction
14. compound made up of carbon, hydrogen, and oxygen atoms; major source of energy for the human body
15. a slight attraction that develops between the oppositely charged regions of nearby molecules
17. macromolecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorus
19. atom of an element that has a number of neutrons different from that of other atoms of the same element
20. compound with an amino group (−NH2) on one end and a carboxyl group (−COOH) on the other end
Down
2. energy needed to get a reaction started
3. material composed of two or more elements or compounds that are physically mixed together but not chemically combined
4. substance formed by the chemical combination of two or more elements in definite proportions
5. mixture of two or more substances in which the molecules of the substances are evenly distributed
7. negatively charged particle; located outside the atomic nucleus
12. bond formed when one or more electrons are transferred from one atom to another
13. attraction between molecules of different substances
16. substance consisting entirely of one type of atom
18. atom that has a positive or negative charge