Introduction 
sugar-phosphate 
backbone 
Figure 9- The famous DNA dou- 
ble helix. 
Prom Alberts, B., Bray, D., 
Lewis, J., Raff, M., Roberts, K., 
and Watson, J.D. 1989. Molecu- 
lar Biology of the Cell, 2nd edi- 
tion. New York: Garland, p. 99. 
Figure 10. An illustration of how DNA is repli- 
cated so as to form two new strands that are 
exactly complementary to the original DNA 
sequences from which they derive their 
sequences. 
From Raven, P.H., and Johnson, G.B. 
1988. Understanding Biology. St. Louis, MO: 
Times Mirror /Mosby College Publishing, 
p. 277. 
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