Nutrition
Nutrition is the process to transfer a source of energy from outside to the body of an organism for maintaining life living structures.
Mode of nutrition
it means method of procuring food by an organism. Different organisms have different modes of nutrition . Two modes of nutrition autotrophic nutrition and heterotrophic nutrition.
Autotrophic nutrition
this mode of nutrition is performed by autotrophs examples green plants and some bacteria. On this mode of nutrition is performed by autotrophs examples green plants and some bacteria. On the basis of the sources of energy utilised for preparation of food
The basis of the sources of energy utilised for preparation of food .
Autotrophs can be of two types.
- Photosynthetic autotrophs : green plant fulfill their carbon and energy requirements for the process of photosynthesis using sunlight as a source of energy. such organisms are called photo autotrophs.
- Chemosynthetic autotrophs: bacteria utilizes chemical energy instead of light energy to synthesise their organic materials . Such organisms are called chemoautotrophs.
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Plant nutrition: Photosynthesis
A complex process by which green parts of the plant synthesise organic food in the form of carbohydrates from carbon dioxide and water in the presence of sunlight and chlorophyll.
The raw materials required for photosynthesis are carbon dioxide, water, light energy and chlorophyll.
Its end products are glucose and oxygen.
carbohydrates are utilised for providing energy to the plant. The remaining carbohydrates which are not used immediately are stored in the form of starch, that serves as the internal energy reserve and is used by the plant whenever required.
Glycogen serves as an internal energy reserve to be used, when required in animals.
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Events in photosynthesis.
leaves are the major photosynthetic organs of a plant. They have large surface area, vascular supply for food and water supply and apparatus for gaseous exchange. Leaves contain green dots that are cell organelles called chloroplast.
chloroplast are the site of photosynthesis as the content chlorophyll pigment, which traps the solar energy from the sun.
in the cross section of leaf, chloroplasts appear as numerous disc like organelle just below the upper epidermis.
The structure of a leaf can be broadly studied under cross section of a leaf.
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Its end products are glucose and oxygen.
carbohydrates are utilised for providing energy to the plant. The remaining carbohydrates which are not used immediately are stored in the form of starch, that serves as the internal energy reserve and is used by the plant whenever required.
Glycogen serves as an internal energy reserve to be used, when required in animals.
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Events in photosynthesis.
- Absorption of light energy by chlorophyll.
- Conversion of heat energy into chemical energy and splitting of water molecules into hydrogen and oxygen.
- Reduction of carbon dioxide to carbohydrates.
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Site of photosynthesis:chloroplast
leaves are the major photosynthetic organs of a plant. They have large surface area, vascular supply for food and water supply and apparatus for gaseous exchange. Leaves contain green dots that are cell organelles called chloroplast.
chloroplast are the site of photosynthesis as the content chlorophyll pigment, which traps the solar energy from the sun.
in the cross section of leaf, chloroplasts appear as numerous disc like organelle just below the upper epidermis.
The structure of a leaf can be broadly studied under cross section of a leaf.
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Main Parts of leaf
- Epidermis : it is the outermost layer of the leaf and consists of two distinct points that is upper epidermis with no chloroplast. It protects the internal list issue by preventing excessive water loss to evaporation and lower epidermis, which contains stomata and helps in gaseous exchange in plant.
- Stomata: there are tiny pores, mostly found in the lower epidermis, which allow gases to enter and exit the lift more rapidly between the plant and atmosphere.
- Guard cell: These are bean shaped cells that frame the stomatal openings. they contain chloroplast and have cell wall.
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Conditions necessary for photosynthesis
- Sunlight : it affects the rate of photosynthesis by its wearing intensity quality and duration.
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