This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Basics of DNA, Subject name: Biochemistry
Hershey chase experiment was done on: 
Select and explain. 
A. Lactobacillus, B. Tuberculous bacteria, C. Bacteriophages, D. Mycoplasma
C: Bacteriophages
Answer: C: Bacteriophages 
Explanation: Hershey chase experiment To see whether it is DNA or protein which enters host cell to act as genetic material. Done on bacteriophages. Viruses don't have their own machinery of reproduction. So they attach to the host cells (bacteria) and transfer their genetic material into the host cell and bacteria then produce viruses. Host for infection was E.coli bacteria. E.coli bacteria that were infected by radioactive DNA viruses were radioactive but the ones that were infected by radioactive protein viruses were non-radioactive.