Friday, February 26, 2016
Organisms which exhibit autotrophic nutrition are called Autotrophs. These organisms are able to synthesise their nutrients from simple inorganic compounds.
They require minerals, water and carbon dioxide for their growth. They are capable of converting carbon dioxide into various complex organic compounds.
However, they require energy for this purpose. Depending on how they obtain the energy for converting carbon dioxide to organic compounds, there are two types of autotrophs – photoautotroph and chemoautotroph.
Several bacteria(such as green bacteria, purple bacteria and cyanobacterial) can use light as a source of energy and synthesise complex organic molecules.
Similarly, All the algae and higher plants use light as source of energy. These autotrophic organisms are called photoautotrophic organisms
These organisms have special pigments is their body to trap the light energy which drives other reactions.
Second group of autotrophs are chemoautotrophs. These organisms obtain energy by oxidizing simple inorganic compounds.
Such as hydrogen, iron containing compounds, sulphur, hydrogen sulphide, ammonia, nitrite, and other nitrogen containingcompounds. However, all these organisms require carbon dioxide as a source of carbon atoms.