This happens when a detection is accomplished through heuristics. There is no such thing as a heuristic virus. As a technical concept, everything in malware detection is done via heuristics.
Photosynthesis is the process in which plants (also autotrphoic protists and some bacteria) use light energy, from the Sun, to make sugars and organic food molecules from CO2 and water (H2O). This process is essential for the formation of not only energy, but also for the formation of glucose for purposes of structure.
Photosynthesis is the plant process where light energy is used to generate the production of ATP. The ATP so formed is used to form the bonds between carbon dioxide molecules and hydrogen atoms released from water by the light energy. The process forms sugar (glucose) molecules and produces oxygen as a waste product. At a glance, the equations: sugar + oxygen --> carbon dioxide + water + ATP energy (cellular respiration) and carbon dioxide + water + sun's energy --> sugar + oxygen (photosynthesis) look to be the reverse of each other.