Viruses are not capable of respiration. Respiration occurs in cells, whereas viruses have a simple structure and no cells. Respiration, also known as cellular respiration, is defined as the chemical process by which the cells of an organism oxidize and break down organic matter and produce energy. Respiration is categorized into aerobic and anaerobic respiration. Aerobic respiration takes place in the cytoplasmic matrix and mitochondria and anaerobic respiration takes place in the cytoplasmic matrix. Viruses do not have cells and they lack the genetic information that encodes the mitochondria. The significance of respiration to an organism is to provide energy for the organism’s life activities as well as raw materials for the synthesis of other compounds in the body. Viruses lack the enzyme system necessary for proliferation and can only proliferate within living cells. Therefore, viruses are also not necessary for respiration. It follows that viruses cannot and do not need to respire.