Until Hershey and Chase showed that DNA was the genetic molecule of the phages they studied, what class of molecules was considered the best candidate for carrying genetic information and why?

• A. Amino acids because of all the ways they can join together
• B. Carbohydrates because they are found in abundance in all organisms
• C. Sterols because of the different variations on their ring structure
• D. Nucleoside triphosphates because of the ability to add and remove phosphate groups
• E. Proteins because they were thought to be the only molecule with both the variety and specificity of function to account for the array of heritable traits observed

Answer: (E)

Verified step by step guidance

1. Understand the historical context: Before the discovery by Hershey and Chase, scientists were trying to identify the molecule responsible for heredity. The complexity and diversity of proteins made them a prime candidate.
2. Consider the properties of proteins: Proteins are composed of 20 different amino acids, which can be arranged in countless combinations, leading to a vast array of structures and functions.
3. Evaluate the specificity of proteins: Proteins can perform highly specific functions due to their unique three-dimensional structures, which are determined by the sequence of amino acids.
4. Compare proteins to other molecules: Other molecules like carbohydrates, sterols, and nucleoside triphosphates lack the diversity and specificity that proteins exhibit, making them less likely candidates for carrying genetic information.
5. Recognize the shift in understanding: Hershey and Chase's experiments demonstrated that DNA, not proteins, was the genetic material, changing the scientific consensus and leading to further research into the role of DNA in heredity.