CLASS – 7 : CHAPTER – 1 NURITION IN PLANTS KEY WORDS, SUMMARY AND FACTS

CLASS – 7 : CHAPTER – 1 NURITION IN PLANTS

LESSON NOTES – KEY WORDS, SUMMARY AND FACTS    

KEYWORDS:

·       Autotrophic nutrition: mode of nutrition in which organisms prepare their own food.

·       Chlorophyll: green pigment present in the leaves of plants.

·       Heterotrophic nutrition: mode of nutrition in which organisms do not prepare their own food; they derive their food from plants, or animals, or both.

·       Host: the living organisms from which a parasite derives its food.

·       Insectivorous plants: insect-eating plants.

·       Nutrition: the process, of obtaining, and utilising, food by a living organism.

·       Nutrients: Carbohydrates, proteins, fats, vitamins and minerals are components of food. These components of food are necessary for our body and are called nutrients.

·    Parasitic nutrition mode: of nutrition in which non-green plants live on other living organisms and obtain their food from them.

·       Photosynthesis: the process through which green plants prepare their own food.

·       Saprotrophic nutrition: mode of nutrition in which some plants feed on dead and decaying matter.

·       Stomata: tiny pores that are present on the surfaces of leaves; useful for exchange of gases.

·       Vessels: channels, to transport water and minerals, to different parts of the plant.

    SUMMARY:

·       All organisms need food and utilise it to get energy for growth and maintenance of their body.

·       Green plants synthesise food for themselves by the process of photosynthesis. They are autotrophs.

·       Plants like Cuscuta are parasites. They take food from the host plant.

·       Plants use simple chemical substances like carbon dioxide, water and minerals for the synthesis of food.

·       Chlorophyll, water, carbon dioxide and sunlight are the essential requirements for photosynthesis.

·       Complex chemical substances such as carbohydrates are the products of photosynthesis.

·       Solar energy is absorbed by the chlorophylls present in leaves/plants.

·       Oxygen is produced during photosynthesis.

·       Oxygen released in photosynthesis is utilised by living organisms for their survival.

·       Many fungi derive nutrition from dead and decaying matter. They are saprotrophs.

·       A few plants and all animals are dependent on others for their nutrition and are called heterotrophs.

    FACTS:

 ·    Euglena is an organism that shows both autotrophic and heterotrophic modes of nutrition. It has both plant and animal-like features.

·    Some plants have leaves that are not green in colour. Such leaves contain chlorophyll but the green colour is masked due to the presence of other coloured pigments. The presence of additional pigments causes other leaf colours, such as red in coleus and purple in red cabbage.

      However, such leaves can still perform photosynthesis. However, some variegated leaves have yellow patches. Such yellow areas on the leaf do not contain any chlorophyll and hence, cannot perform photosynthesis.

 Hence, solar energy is the ultimate source of energy for all living organisms.

·       Both deer and lion depend on plants. If there were no plants, deer would not survive and if there were no animals, like deer, the lions, too, would die. Plants, in turn, depend on solar energy.

·       You must have observed

(i)          A white cottony growth on leather articles in humid weather

(ii)          Mushrooms growing on rotting wood and

(iii)         Greenish-blue patches on rotting fruits. A cottony growth, developing into coloured patches, is a common occurrence on stale bread.

These organisms belong to the group of fungi and bacteria, and they exhibit the saprotrophic mode of nutrition.