For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger signal than labeling the phosphates. Why won't this experiment work? A) There is no radioactive isotope of nitrogen.
B) Radioactive nitrogen has a half-life of 100,000 years, and the material would be too dangerous for too long.
C) Avery, MacCloud and McCarty already did this.
D) Although their are more nitrogens in a nucletotide, labeled phosphates actually have 16 extra neutrons; t Shift Ctrl herefore, they are more radioactive.
E) Amino acids (and thus and proteins proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA.
Match the scientist(s) with his/her/their contributions.
A. Watson and Crick
B. Friedrich Miescher
C. Hershey and Chase
D. Friedrick Sanger
E. Rosalind Franklin
F. Linus Pauling
G. Avery, MacCloud and McCarty