Chapter 19.5, Problem 1CS

Gene Transfer Between Bacteria

Core Skill: Connections Look back at Figures 11.1 and 11.2. How did the phenomenon of transformation allow researchers to demonstrate that DNA is the genetic material?

Figure 11.1 Griffith’s experiments showing that genetic material can be transferred from one bacterium to another. Note: To determine if a mouse’s blood contained live bacteria, a sample of blood was also applied to solid growth media. (This part of the procedure is not shown.) For steps 1 and 4, smooth bacterial colonies were observed. For step 2, no bacterial colonies were observed because the type R cells were killed by the immune system of the mouse.

Figure 11.2 The Avery, MacLeod, and McCarty experiments that identified DNA as Griffith’s transformation principle—the genetic material.