1	2				3					4
5
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7			8												9
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11					12
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14											15
							16						17
				18						19
			20												21
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							23

Across 1. atoms of the same element with different #'s of neutrons 7. substance made by by only one type of atom that cannot be broken down by chemical means 10. one 13. chemical bond formed through the electrical force between oppositely charged ions 14. fiber 16. long chain of amino acids 19. two 20. molecule composed of one or more polypeptide chains 22. an elementary particle having no charge mass slightly greater than that of a proton 23. one unit

Down 2. sugar 3. a positively charged elementary particle that is a fundamental constuent of all atomic nuclei 4. moecule composed of sugars 5. enzyme 6. smallest basic unit of matter 8. the smallest physical unit of an element or compound 9. basic building blocks of protein molecules 11. an elementary particle that is a fundamental constituent of matter having a nrgative charge 12. organelle composed of a double membrane that acts as the storehouse for most of a cells DNA 15. enzyme that breaks or makes covakent bonds between amino acids 16. many units together 17. many 18. highly branched polysaccharide used as food storage in plants 21. atom that has gained or lost one or more electrons