What is the point of cellular respiration and how is it similar to our circular system?

The purpose is to produce cellular energy for life to exists. As the name implies, cellular respiration literally means "cellular breathing"; hence it is technically what our circulatory system is doing but on the microscopic scale. The circulatory system moves oxygen-rich blood all throughout the body via blood vessels, meanwhile facilitating the movement of carbon dioxide (cellular waste) to the lungs where it is expelled. In cellular respiration, each individual cell takes in oxygen and glucose and converts it into useable energy that the cell can use to work.