Question

What is autotrophic nutrition? Give one example of autotrophs.

Answer 1

Hint: The nutrition in which organisms make their food by their own. It does not depend on others for their food. Autotrophs mainly act as producers in the food chain as they can make their food by their own. They use light energy and water and synthesize their food. Plants are the most basic example of autotrophs. They take inorganic molecules into their body and change them into organic form.

Complete answer:
There are two type of autotrophic nutrition namely :-
Chemoautotrophic nutrition:- the type of nutrition where organisms use chemical energy to make their food. This type of nutrition is synthesized mainly by the fixation of carbon dioxide . The energy required by chemoautotrophs comes from the oxidation of several inorganic molecules like iron , sulphur. They utilize energy by the oxidation of electron donors.
For example anabaena and nostoc which are examples of eubacteria possess this type of nutrition.
Photoautotrophic nutrition :- the type of nutrition where organisms use light energy to make their own food. They use light energy and convert the water and carbon dioxide into organic molecules such as glucose. They mainly act as producers in the food chain and occupy the first trophic level.
For example cyanobacteria is a common example of this type of nutrition.

Note:
Chemoautotrophic bacteria like Nostoc fix nitrogen in the atmosphere and live in specialised cells called heterocysts. They often form algal blooms. These bacteria oxidise various inorganic substances such as nitrates , nitrites and ammonia and use the released energy for ATP production. They play a great role in recycling nutrients.