Chapter 16, Problem 16.1PS

Prior Knowledge. Virtually every experiment performed by biologists builds on knowledge provided by earlier experiments.

1. (a) Of what significance to Avery and his colleagues was the finding (made in 1932 by J. L. Alloway) that the same kind of transformation of R cells into S cells that Griffith observed to occur in mice could also be demonstrated in culture with isolated pneumococcal cells?
2. (b) Of what significance to Hershey and Chase was the following suggestion (made in 1951 by R. M. Herriott)? “A virus may act like a little hypodermic needle full of transforming principles; the virus as such never enters the cell; only the tail contacts the host and perhaps enzymatically cuts a small hole through the outer membrane and then the nucleic acid of the virus head flows into the cell.”
3. (c) Of what significance to Watson and Crick were the data of their colleagues at Cambridge suggesting that the particular forms in which A, G, C, and T exist at physiological pH permit the formation of specific hydrogen bonds?
4. (d) How did the findings of Hershey and Chase help explain an earlier report (by T. F. Anderson and R. M. Herriott) that bacteriophage T2 loses its ability to reproduce when it is burst open osmotically before adding them to a bacterial culture?