Choose the one most appropriate answer for each.
-Chargaff
A)Discovered that the hereditary system of one strain of bacteria could be transformed by the hereditary system from another strain of bacteria
B)First to describe DNA and extract it from cell nuclei
C)Discovered that DNA-digesting enzymes prevented bacterial transformation
D)The first to build an accurate model of DNA and to describe it explicitly in a publication
E)The first to demonstrate, through the use of radioactive isotopes, that DNA, not protein, is the genetic material
F)Provided two important clues to the structure of DNA; one clue is that A = T and the other is that C = G
G)Worked at King's College at the same time as Franklin
H)Obtained excellent x-ray diffraction photographs that suggested that DNA was a long, thin molecule with regularly repeating units

Question

Quizplus · Accepted Answer

Chargaff discovered that in DNA, the amount of adenine (A) equals the amount of thymine (T) and the amount of cytosine (C) equals the amount of guanine (G), providing the important clue that the base pairs must be complementary.

Answer: C
 Chargaff discovered that DNA-digesting enzymes prevented bacterial transformation, which eventually led to the understanding that DNA was the genetic material responsible for bacterial transformation.

Answer: E
 Chargaff was the first to demonstrate, through the use of radioactive isotopes, that DNA, not protein, is the genetic material.

Answer: B
 Although Chargaff made significant contributions to the understanding of DNA structure and function, he was not the first to describe DNA or extract it from cell nuclei. This honor belongs to Friedrich Miescher, who isolated a substance he called nuclein from the nuclei of white blood cells in the late 1800s.

Therefore, the best choices are F, C, E or B.

Choose the One Most Appropriate Answer for Each