Question

What is the difference between a chemoautotroph, heterotroph, and autotroph?

Answer 1

Hint: Animals, plants, bacteria, and fungi do not obtain food by the same process or method. While some of them prepare their food, others are dependent on those who prepare their food. Plants and some bacteria like cyanobacteria have the green pigment chlorophyll to synthesize food, while animals, fungi, and other bacteria depend on those organisms who prepare their food.

Complete answer:

Characteristics	Autotrophs	Heterotrophs	Chemoautotrophs
Definition	They are organisms that manufacture their organic food from inorganic raw materials.	They are organisms that obtain readymade organic food from outside.	Organisms that make their food by chemosynthesis in which they use chemical energy to produce carbohydrates.
Chloroplast	Present	Absent	Absent
Energy source	Light energy is used.	Can derive it directly or indirectly from other organisms.	By the oxidation and reduction of inorganic compounds such as iron, sulfur, and magnesium.
Energy storage	Store light energy and chemical energy.	Can’t store energy.
Types	Photoautotrophs and chemoautotrophs.	Consumers, detritivores, and saprotrophs.	Methanogen, nitrifiers, anammox bacteria, sulfur oxidizers, and reducers, and thermoacidophiles.
Dependency	Independent	Rely on autotrophs for their food.	Independent
Role	Producers	Consumers	Producers
Food chain level	Primary producer	Secondary or tertiary consumers	Primary producers
Example	Green plants, photoautotrophic bacteria, blue-green algae	Humans, Animals, Fungi, etc.	Sulfur oxidizing bacteria, nitrogen oxidizing bacteria, iron-oxidizing bacteria.

Note:
Following stages occur in the process of photosynthesis: Chlorophyll molecules of chloroplast first absorb light energy. Absorbed light energy splits water molecules into hydrogen and oxygen. In this step light energy is converted into chemical energy. In the last step, carbon dioxide is reduced into the final product of photosynthesis which is carbohydrates.