Question 1
Question: What is nutrition?
Answer: Nutrition is the process by which an organism obtains food which is used to provide energy and materials for its life sustaining activities.
Question 2
Question: What are nutrients?
Answer: Nutrients are various organic and inorganic substances required by the organisms to carry out their functions.
Question 3
Question: What is the importance of nutrients?
Answer: The various nutrients carry out different functions such as
1) energy production
2) synthesis of materials for growth and repair of the tissues
3) synthesis of materials necessary for carrying out and maintaining life functions
4) synthesis of materials for immune system
Question 4
Question: What are the various modes of nutrition?
Answer: The two main methods of nutrition are autotrophic and heterotrophic. These are further divided into different types as follows:
Autotrophic nutrition
In this type, the organisms synthesize their own food. It is of two types:
1) Photoautotrophic - The source of energy is sunlight.
2) Chemoautotrophic - The source of energy are the chemicals.
Heterotrophic nutrition
In this type, the organisms are directly or indirectly dependant on the autotrophs. It is of the following types:
1) Holozoic - The organisms ingest food and then digest, absorb and assimilate it.
2) Saprotrophic - The orgainsms feed on dead plants and animals digesting them before feeding.
3) Symbiotic - The association between dissimilar individuals. May be
4) Mutualistic - where both the partners benefit.
5) Parasitic - where one partner benefits and the other is harmed.
6) Commensalism - where one partner benefits and the other is not affected
Question 5
Question: What is autotrophic nutrition?
Answer: The process by which the organisms synthesise their own food using carbon dioxide and water is called autotrophic nutrition. For example, green plants, sulphur bacteria, etc.
Question 6
Question: How are the autotrophs classified?
Answer: Autotrophs are classified based on their source of energy. If they use the light energy of the sun, they are called photoautotrophs. If they use chemical energy of certain compounds such as ammonia and nitrites, they are called chemoautotrophs.
Question 7
Question: What are photoautotrophs?
Answer: Those organisms that synthesize food with the help of the light energy of the sun, carbon dioxide and water are called photoautotrophs. The process of synthesis of food in this manner is called photosynthesis. For example - cyanobacteria(blue-green bacteria, prokaryotes), algae and all green plants.
Question 8
Question: What is heterotrophic nutrition?
Answer: The process of nutrition where the organisms obtain their food from other organisms. For example, most of the bacteria, fungi and all animals. They are all dependant on autotrophs directly or indirectly.
Question 9
Question: Why are the green plants called producers?
Answer: The green plants trap the sun's energy and the raw materials in food molecules. They form the basis of sustenance for all the organisms directly or indirectly. They are also called the producers as they produce food for all other organisms.
Question 10
Question: What is photosynthesis?
Answer: Photosynthesis is a process which utilises carbon dioxide and water in the presence of sunlight and chlorophyll to synthesize carbohydrates like glucose.
