Construct an explanation to describe the cycling of matter and energy that occurs during photosynthesis. Use the chemical equation to provide evidence.

This is the most closely resembles the model. 

Mitochondria produce atp, a high energy compound. atp is used for all sorts of enzyme-mediated reactions, such as making proteins/nucleotides/etc, certain compounds cross the cell membrane, muscles move, etc.  without this source of energy, a cell will die. it will not be able to repair itself, defend against pathogens, etc.