Our bodies are made from cells and these cells go through a life cycle (creation and death). Cell death, or apoptosis, is a complex process and has many stages. This image is an artistic representation of one of those stages.  

 

Apoptosomes, the green ring structures, function as a 'gatekeeper' for cell death and unless they are formed, the cell cannot die. Apoptosome formation occurs after a protein, cytochrome-c, is released from the powerhouse of cells, the mitochondria. Cytochrome-c attaches to a free-floating protein known as Apaf-1, and once attached, those free-floating proteins form a ring, or apoptosome.  

 

Please read this link if you'd like to learn more! Scientific American blog post -- More about Apoptosomes