Chapter 12, Problem 11A

Summary Introduction

To analyze:

The way by which the Hershey-Chase experiment have been different if protein were the genetic material.

Introduction:

Genetic disorders are diseases are caused by mutations in genes or DNA sequence. Common genetic diseases are cystic fibrosis, night blindness, and hemophilia.

Answer to Problem 11A

If protein was present instead of genetic material, then the set of bacteria injected with radioactive sulfur would have been infected.

Explanation of Solution

The main purpose of Hershey and Chase was to prove that DNA is the genetic material. Bacteriophage viruses were cultured in a medium that contained radioactive phosphorus and some were cultured in medium with radioactive sulfur. Viruses grew in radioactive phosphorus has radioactive DNA and viruses grew in radioactive sulfur had radioactive proteins. Both the types of viruses then were allowed to infect E.coli. It was found that radioactive P was only found in bacterial cells and radioactive S was in the surrounding medium. This proved that only DNA entered the bacterial cell, proving that it is the genetic material.

So, if protein was the genetic material, then radioactive sulfur would have been found inside the bacterial cell and not the radioactive phosphorus.