Breathing is also known as internal respiration.
Breathing or external respiration is a physical process in which an organism inhales oxygen and exhales carbon dioxide. It occurs outside the cells and enzymes are not involved. Energy is not released in the process of breathing.
Cellular respiration or internal respiration is a chemical process in which food molecules are broken down into simpler molecules within the cells and energy is produced. Enzymes take part in the process of cellular respiration.