ATG cells refer to autophagy-related cells, which are involved in autophagy. For anyone not in the know, Autophagy is a natural cellular process that helps remove damaged or unnecessary components within cells to maintain their health.

When Buddha says that ATG cells are different proteins by number, it means that there are different types of proteins involved in the autophagy process. These proteins are called ATG proteins.

Each ATG protein has a specific role in regulating and carrying out different steps of autophagy. They work together like a team to ensure that the process of autophagy is properly controlled and executed.

It all just means that there are multiple types of ATG proteins, each playing a unique role in the autophagy process to keep our cells functioning properly.