Erwin Chargaff's work on the composition of nucleic acids began in 1944. His findings, which later became known as Chargaff's rules, detail the specific pairings that occur in double-stranded DNA molecules.

Question

Erwin Chargaff's work on the composition of nucleic acids began in 1944. His findings, which later became known as Chargaff's rules, detail the specific pairings that occur in double-stranded DNA molecules.

According to one of Chargaff's rules, a section of DNA molecule that contains 50 base pairs and has 15 adenine bases must also contain -
A 15 guanine bases
® 15 cytosine bases

© 15 thymine bases

• 15 uracil bases

Answer 1

According to Chargaff's rules, in double-stranded DNA, the amount of adenine (A) always equals the amount of thymine (T), and the amount of guanine (G) always equals the amount of cytosine (C). So if a section of DNA molecule contains 15 adenine bases, it must also contain 15 thymine bases in order to maintain the equal pairing. Therefore, the correct answer is © 15 thymine bases.