Becker's World of the Cell 9th Edition by Lewis Kleinsmith, Jeff Hardin, Gregory Paul Bertoni

Exercise 2

DNA Base Composition. Based on your understanding of the rules of complementary base pairing, answer the following questions;
(a)You analyze a DNA sample and find that its base composition is 30% A, 20% T, 30% G, and 20% C. What can you conclude about the structure of this DNA
(b)For a double-stranded DNA molecule in which 40% of the bases are either G or C, what can you conclude about its content of the base A
(c)For a double-stranded DNA molecule in which 40% of the bases are either G or T, what can you conclude about its content of the base A
(d)For a double-stranded DNA molecule in which 15% of the bases are A, what can you conclude about its content of the base C Would you expect the Tm of this DNA to be above or below 90°C (Hint: Refer to Figure 18-9.)