Scientific Context

Introduction

What if we told you that a simple kitchen blender was used to answer one of the most fundamental questions in biology? That’s exactly what Alfred Hershey and Martha Chase did. At the time, scientists were debating whether DNA or protein carried genetic information. Proteins, with their complexity, seemed like the obvious answer, while DNA was dismissed as too simple. Hershey and Chase designed an experiment to settle the debate once and for all.

What is a Bacteriophage?

The key players in this experiment were bacteriophages, or “phages,” which are viruses that infect bacteria. Here’s what they look like:

• Head (Capsid): The head contains the genetic material of the virus, which in this case is DNA.

• Tail: The tail is a tube-like structure that delivers the DNA into a bacterium.

• Tail Fibers: These fibers help the phage attach securely to the bacterial cell.

Bacteriophages rely on bacteria to reproduce. They attach to a bacterium, inject their genetic material, and take over the bacterial machinery to produce more phages. Eventually, the bacterium bursts (a process called lysis), releasing new phages to infect other bacteria.