Heterotrophic nutrition
Encyclopedia
Heterotrophic nutrition is nutrition
obtained by digesting organic compounds.
Animals, fungi, many prokaryotes and protoctists are unable to synthesize organic compounds to use as food. They are called heterotroph
s.
Heterotrophic organisms have to acquire and take in all the organic substances they need to survive.
All heterotrophs (except blood and gut parasites) have to convert solid food into soluble compounds capable of being absorbed (digestion). When the soluble products of digestion are absorbed they are distributed to various parts of the organism where complex materials (assimilation) or broken down for the release of energy (respiration).
The four main types of heterotrophic nutrition are:
Nutrition
Nutrition is the provision, to cells and organisms, of the materials necessary to support life. Many common health problems can be prevented or alleviated with a healthy diet....
obtained by digesting organic compounds.
Animals, fungi, many prokaryotes and protoctists are unable to synthesize organic compounds to use as food. They are called heterotroph
Heterotroph
A heterotroph is an organism that cannot fix carbon and uses organic carbon for growth. This contrasts with autotrophs, such as plants and algae, which can use energy from sunlight or inorganic compounds to produce organic compounds such as carbohydrates, fats, and proteins from inorganic carbon...
s.
Heterotrophic organisms have to acquire and take in all the organic substances they need to survive.
All heterotrophs (except blood and gut parasites) have to convert solid food into soluble compounds capable of being absorbed (digestion). When the soluble products of digestion are absorbed they are distributed to various parts of the organism where complex materials (assimilation) or broken down for the release of energy (respiration).
The four main types of heterotrophic nutrition are:
- Holozoic nutritionHolozoic nutritionHolozoic nutrition is a method of nutrition that involves the ingestion of liquid or solid organic material, digestion, absorption and assimilation of it to utilize it...
: Complex food is taken into a specialist digestive system and broken down into small pieces to be absorbed. This consists of 5 stages, ingestionIngestionIngestion is the consumption of a substance by an organism. In animals, it normally is accomplished by taking in the substance through the mouth into the gastrointestinal tract, such as through eating or drinking...
, digestionDigestionDigestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....
, absorptionAbsorptionAbsorption may refer to:- Chemistry and biology :* Absorption , absorption of particles of gas or liquid in liquid or solid material* Absorption , a route by which substances can enter the body through the skin...
, assimilationAssimilation (biology)Biological assimilation, or bio assimilation, is the combination of two processes to supply animal cells with nutrients. The first is the process of absorbing vitamins, minerals, and other chemicals from food within the gastrointestinal tract...
and egestion. - Saprobiontic/saprotrophic: Organisms feed on dead organic remains of other organisms.
- Parasitism: Organisms obtain food from other living organisms (the host), with the host receiving no benefit from the parasite.
- Mutualism: A symbiotic relationship between organisms, with each contributing and benefiting from each other.