Question

Describe the experiment of Hershey and Chase to prove that DNA is the genetic material.

Answer 1

The genetic characters are transmitted from parent to offspring with the help of chromosomes. These chromosomes are made up of DNA associated with nucleoproteins. The DNA is transferred through the male and female gametes into the zygote.

Complete answer:
By the beginning of the 19th century, all macromolecules like protein, carbohydrate, DNA, RNA etc. were identified but it was not clear which macromolecule was responsible for the transfer of genetic information from one generation to the next generation. Initially, it was believed that the proteins are the genetic material, not the DNA.
In 1952, Hershey and Chase proved through his classical experiment that DNA is the main genetic material that transfers the genetic information from one generation to another generation.
In his experiment Hershey and Chase used bacteriophage, a virus of bacteria. The bacteriophage is made up of DNA and protein only. The protein makes the outer coat or covering of the bacteriophage and the DNA is enclosed within it. They labelled coat proteins with sulfur-35 and DNA by phosphorus- 32.
After the experiment, the radioactivity of the two components, S35 labelled protein and P32 labelled DNA was measured. It was found that only the DNA enters into the bacterial cell through a hole made by bacteriophage in the bacterial cell wall as the radioactive P32 was found in the cell only. The protein coat remains outside the bacteria because it has a large shape and cannot enter into the bacterial cell and radioactive S35 labeled protein is found outside the bacterial cell. Thus, their experiment proved that their genetic material is DNA, not the protein because it remains outside during the experiment.

Note:
The Hershey and Chase experiment is considered as a milestone in biological sciences because it has clarified one of the biggest questions which macromolecule acts like genetic material? This experiment clarified and suggested that DNA acts as genetic material in most of the organisms.