Wisconsin Esthetics State Board Practice Test

Which of the following is NOT a basic component of proteins?

1. Carbon

2. Oxygen

3. Copper

4. Nitrogen

The correct answer is: Copper

Proteins are essential macromolecules composed of long chains of amino acids, and their fundamental components include carbon, oxygen, nitrogen, and hydrogen. These elements contribute to the structure and function of proteins. Carbon is a primary building block of all organic molecules, including amino acids, which are the monomers that make up proteins. Oxygen is also present, primarily in the carboxyl groups of amino acids. Nitrogen is a critical component of amino groups in amino acids, which defines them as the building blocks of proteins. Copper, however, is not a basic component of proteins. While copper plays various roles in biological systems, such as in enzyme function or as a trace mineral, it is not a structural part of proteins themselves. Therefore, identifying copper as the option that does not belong among the basic components of proteins is the correct choice.