SCIENCE CLASS-7 CHAPTER-1---> NUTRITION IN PLANTS

               CHAPTER-1 ---> NUTRITION IN PLANTS 

Mode of Nutrition in Plants:- Plants are the only organism that can prepare food for themselves by using water, carbon dioxide and minerals.

Autotrophs:- Organisms who make their food by themselves is known as Autotrophs and the mode of nutrition is called Autotrophic. Example of Autotrophs is Plants.

Heterotrophs:- Organisms who depend on other organism for their food is known as Heterotrophs. Animals and human beings are the example of Heterotrophs. 

Stomata:- The tiny pores present on the surface of the leaf which help in exchange of gases through surrondings. These pores surrounded by guard cells. Such pores are called Stomata.

Chlorophyll:-  The leaves have a green pigment called chlorophyll. These green pigment make leaves green. It helps leaves to capture the energy of the sunlight.

Photosynthesis:- The process of making food by the plant in presence of sunlight by using water and carbon dioxide is known as photosynthesis. Chlorophyll cells use carbon dioxide and water to synthesise(prepare) carbohydrates. It is represented by equation--

 Carbon dioxide + water --sunlight+chlorophyll--- > carbohydrate + oxygen 

In this process oxygen is released. The carbohydrates get converted into starch.

Cells:- The bodies of living organisms are made of tiny units called cells. Cells can be seen only under the microscope.

                                                                      Fig:-  Cell

Cell membrane:- The cell is enclosed by a tiny outer boundary. This boundary is called the cell membrane.

 Nucleus:- A Centrally located spherical structure in cell is called Nucleus. 

Cytoplasm:- The nucleus is surrounded by a jelly-like substance called cytoplasm. 

Point to Note:- Besides leaves, photosynthesis also take place in other green part of plant- in green stem and green branches of plant.

 Algae:- Algae is slimy, green patches in ponds or in other stagnant water bodies. They contain chlorophyll which gives them green colour. 

                                                                     Fig:-  Algae

Parasite:- A parasite is an organism that lives on or in a other organism and gets its food. Example of Parasite is Cuscuta(Amarbell)

 Host:- A Host is an organism on which Parasite depend for their food and shelter.

 Insectivorous Plants:-  Some plants trap insects and digest them. Such insect-eating plants are called Insectivorous plants. These type of plants do not full fill their nutrients through photosynthesis. Example:- Venus flytrap, Pitcher plant etc.

                                                           Fig:-  Venus Flytrap

Saprotrophs:- Organism which take nutrients in solution form from dead and decaying matter, such type of organism is known as Saprotrophs. The mode of nutrition is known as Saprotrophic nutrition. Fungi is the example of Saprotrophs. 

                                                       Fig:-  Fungi on Bread

Symbiotic relationship:- Some organisms live together and share shelter and nutrients. Such sharing type relationship is called Symbiotic relationship. For example, some fungi live in the roots of trees. The tree provides nutrients to fungus and in return , receives help from it to take up water and nutrients from the soil.

Rhizobium:- Plants need nitrogen for growth but plant can not take atmospheric nitrogen. They need nitrogen in a soluble form. The Bacterium called Rhizobium can take atmospheric nitrogen and convert it into a soluble form. But Rhizobium cannot make its own food.So it lives in the roots of gram, peas, moong beans and other legumes and provides them with nitrogen.