Class 10 Science Solutions English Medium

Nutrition

1. Nutrition: The process in living organisms in which an organism converts complex substances into simpler substances through biochemical processes, obtains and uses energy, is called nutrition.

Example of a biochemical process:

(i) The process of photosynthesis in plants

(ii) Digestion in animals

The process of making food in green plants is called photosynthesis. In this process organisms obtain simple substances in the form of carbon dioxide and water from inorganic sources. Such organisms are called autotrophs. Example: Green plants and some bacteria having chlorophyll etc.

Enzymes: To break down complex substances into simpler substances, organisms use certain biocatalysts which are called enzymes.

Types of Nutrition: 

There are two types of nutrition. 

1. Autotrophic Mode of Nutrition: Autotrophic nutrition is the type of nutrition in which organisms synthesize organic matter (food) from inorganic sources on their own. This type of nutrition is done by green plants and autotrophic bacteria.

Examples: All green plants and some bacterias which perform photosynthesis. 

2. Hetrotrophic Mode of Nutrition: The mode of nutrition in which the organism obtains its food from other sources. In this, the organism gets its food from plant sources or from animal sources.

Examples: Algee, Fungus, Man, All Animals, etc.

Types of Hetrotrophic Nutrition: 

There are three types of hetrotrophic nutrition. 

(i) Saprophytic Nutrition: The method of nutrition in which living beings feed themselves from dead and decaying organic matter. Such method of nutrition is  called saprophytic nutrition. This type of nutrition occurs in fungi and most bacterias.

(ii) Parasitic Nutrition: Parasitic nutrition is the method of nutrition in which organisms take their food and habitat (shelter) from another organism and absorb their nutritional source is called parasitic nutrition.

Two types of organisms are involved in this process.

(i) Host: The organism from which parasites absorb food is called host.

(ii) Parasite: Parasites are those organisms that live in the body of the host and absorb their own food and use habitat. For example - Plasmodium found in mosquitoes, tapeworm found in human intestine, roundworm, zoo etc. While in plants, cuscuta.

(iii) Holozoic Nutrition : A method of nutrition in which life energy is obtained by ingestion and digestion of organic matter obtained from plant and animal sources. That is, he takes the food, digests it and then takes it out. For example, humans, amoeba and all animals.

Nutrition in Amoeba: Amoeba also receives nutrition like humans and digests inside the body.