What is the primary purpose of agarose gel electrophoresis?

The primary purpose of agarose gel electrophoresis is indeed the separation of DNA fragments. This technique utilizes an agarose gel matrix that allows for the effective separation of nucleic acids based on their size. The technique operates under the principles of electrophoresis, where an electric current is applied to the gel, causing negatively charged DNA fragments to migrate towards the positive electrode. Smaller DNA fragments move through the gel more easily and quickly than larger ones, resulting in a well-defined separation pattern.

This method is crucial in molecular biology, genetics, and forensics, as it can be used for DNA analysis, including sizing of DNA fragments, checking the integrity of DNA, and even purification for subsequent cloning or sequencing. In contrast, other options such as the separation of proteins, lipids, or gases involve different techniques that are not based on the same principles or the use of agarose gel, thus confirming that the focus of agarose gel electrophoresis is specifically on DNA.