Question

Which of the following model organisms were used in experiments demonstrating that DNA was the genetic material?

A) mice
B) amoeba
C) humans
D) tobacco plants
E) bacteria and bacteriophages

Answer 1

Alfred Hershey and Martha Chase conducted experiments with bacteria and bacteriophages and proved that DNA, not protein, is the genetic material by tracking radioactive phosphorus that only labeled the DNA.

Step-by-step explanation:

The experiments demonstrating that DNA was the genetic material were conducted using E) bacteria and bacteriophages. Specifically, Alfred Hershey and Martha Chase performed groundbreaking experiments in 1952 with a type of virus known as a bacteriophage, which infects bacteria.

They labeled one batch of bacteriophages with radioactive sulfur (³3S;) to label the protein coat, and another with radioactive phosphorus (³2P;) to label DNA. Because phosphorus is found in DNA but not protein, they were able to track which molecules entered the bacterial cells and concluded that only the DNA, not the protein coat, was injected into the cells, providing conclusive evidence that DNA is the carrier of genetic information.