Nutrition[edit | edit source]
Nutrition is intake of food, absorption, assimilation, biosynthesis, catabolism and excretion. Nutritional science studies how the body breaks food down (catabolism) and how it repairs and creates cells and tissue (anabolism) using the assimilated nutrients. Catabolism and anabolism combined can also be referred to as metabolism.
There are 6 essential nutrients that our body needs to function properly. Nutrients are compounds in foods essential to life and health, providing us with energy, the building blocks for repair and growth and substances necessary to regulate chemical processes. They are Carbohydrates (CHO), Lipids (fats), Proteins, Vitamins, Minerals and Water.
Modes of Nutrition[edit | edit source]
Autotrophic nutrition[edit | edit source]
In autotrophic nutrition, an organism makes its own food from simple raw materials. Such organism are called autotrophs.
They can be of 2 types:
- Photoautotrophs: Organisms that make food with the help of photosynthesis using light.
- Chemoautotrophs: Organisms that make food using inorganic energy sources such as hydrogen sulphide, elemental sulphur, ferrous iron, molecular hydrogen, and ammonia.
Heterotrophic nutrition[edit | edit source]
In heterotrophic nutrition organisms obtain food from other organisms. As heterotrophs depend on other organisms for their food, they are also called consumers. All animals and non-green plants like fungi come under this category.
They can be broadly divided into 2:
- Holozoic nutrition: In holozoic nutrition complex organic substances are ingested (taken in) without it being degraded or decomposed.eg; amoeba, humans, cows, pitcher plant
- Parasitic nutrition: In this type of nutrition, organisms, or parasites, live on or inside other living organisms, called hosts, and obtain their food from them.eg; Cuscuta (akash-bel), Cassytha (amar-bel), hookworms, tapeworms, leeches, etc.
Saprotrophic Nutrition[edit | edit source]
Nutrition in which organisms(Saprotrophs) derive their food from dead organisms. They secrete enzymes that are released on food material outside their body. These enzymes break down complex food into simple forms. Common examples of saprotrophs are fungi (moulds, mushrooms, yeasts) and many bacteria.
- ↑ "Nutrition". www.who.int. Retrieved 2020-04-09.