Final answer:
Most bacteriophages consist of a protein coat called the capsid, and a nucleic acid core, which may contain either DNA or RNA. This structure enables them to infect host cells by injecting the nucleic acid into the cell, leaving the capsid outside. The Hershey and Chase experiment demonstrated conclusively that DNA is the genetic material in phages, not protein.
Step-by-step explanation:
Most bacteriophages consist of only a protein coat and a nucleic acid core. The correct choice from the provided options is b. Protein, nucleic acid. Bacteriophages, often known simply as phages, have a simplified structure without a cellular makeup. They contain a capsid, which is the protein coat that encases the viral genetic material. This genetic material forms the nucleic acid core, which can be either DNA or RNA. The capsid protects the nucleic acid and aids in delivering it to the host through the infection process whereby only the phage's nucleic acid enters the bacterial cell.
Historically, the Hershey and Chase experiment provided conclusive evidence that the genetic material of a phage is DNA and not protein. They used radioactive isotopes to label the nucleic acids and proteins separately, discovering that it was the DNA that entered the bacterial cells, not the protein of the capsid, suggesting that DNA was the genetic material responsible for replication within bacteria.