Question

What are the three ways in which bacteria obtain food?

Answer 1

Hint: The main process of food production is in the same way as plants produce their own food since bacteria contain plastids. The other method for obtaining food is by absorbing food through other organisms.

Complete answer
The three ways by which bacteria obtain food are photosynthesis, chemosynthesis, and symbiosis.
Photosynthesis - The organisms that are capable of producing their own food known as autotrophs. Blue-green and purple and green photosynthetic bacteria come under this category. To make their own food they require certain raw materials that include carbon dioxide, light energy, chlorophyll, and water. Those autotrophs that use energy from the sun are called photoautotrophs. Inorganic sources are used by autotrophs to make their food and they are also commonly referred to as primary producers because they occupy the base of the food chain.
Chemosynthesis -In this process, the organisms need chemical energy for the process of making food. The organism here are divided into two categories: the first is chemoautotrophs (here the bacteria will break the inorganic substances or chemicals that are obtained from the surrounding environment through biogeochemical cycles and gain energy by it), and the second is the chemoheterotrophs (Here the organisms break the organic compounds that includes the dead organic matters, waste products, etc to gain energy. They are helpful in continuing the mineral cycles of the environment and thus are helpful in the continuation of life.
Symbiosis - Any link between two or more biological species is symbiosis. Usually, such partnerships are long-term and have a powerful effect on one or both species' fitness. Symbiotic relationships are defined by rewards and physical relationships. Here both the organisms are benefited but may sometimes be beneficial for only one species.

Note:
Symbiosis is of three types:
1) Mutualism is a relationship that is normal in nature, where both organisms profit. There are several examples of mutualistic bacteria in the gut in microbiology that promote digestion in both humans and animals.
2) Commensalism is a specific relationship in which one organism gets profit and the other remains unaffected. In their bodies, humans host a number of commensal bacteria that do not harm them but depend on them for survival (e.g. dead skin eating bacteria).
3) Parasitism is a relationship in which one species is benefited while the other one is harmed. An example is the human body and lice.