NCERT Solutions for Class 7 Science Chapter 1 - Nutrition In Plants

Answer:

Heterotrophs are the organisms that take in food prepared by other organisms. Autotrophs are the organisms the prepare their food from simple substances such as water and carbon dioxide. Parasites are the organisms that live on or in other organisms called the host and derive their nutrition from them. Saprotrophs are the organisms that take their food from dead and decaying matter.
Hence, the correct answer is option (b).

Answer:

Photosynthesis is the process used by plants to make their own food using simple substances such as water, carbon dioxide and some minerals. The presence of sunlight and the green pigment, chlorophyll is also essential for photosynthesis to occur. Chlorophyll absorbs the energy of the sunlight. This energy is used to synthesise food from carbon dioxide and water.
Hence, the correct answer is option (b).

Answer:

Among the given four statements, statements (i) and (iv) are correct and statements (ii) and (iv) are incorrect. Most animals are heterotrophs, not autotrophs because they cannot prepare their own food and depend on plants for their nutrition. Carbon dioxide and water are the raw materials for photosynthesis so carbon dioxide is required for photosynthesis.
Hence, the correct answer is option (a).

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Some plants such as pitcher plant live in places where the soil is poor in nutrients such as nitrogen. These plants can synthesis their own food through photosynthesis but in order to meet their requirements of nitrogen, these plants have modified their plant parts to trap insects. The trapped insects are then digested to absorb their nutrients.
Hence, the correct answer is option (b).

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Yeast, mushroom and bread mould are fungi that grow on dead and decaying matter and absorb their nutrients from it. Such a mode of nutrition is called saprophytic nutrition.
Hence, the correct answer is option (c).

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Numerous small openings surrounded by two guard cells present on the lower surface of a leaf are called stomata. The broad, flat and green part of the leaf is called the lamina. The central thick part at the centre of the leaf is called the midrib. The thin lines branching out from the midrib are called veins.
Hence, the correct answer is option (a).

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In the given case, two organisms are good friends living together and both are beneficial for each other - one provides shelter, water and nutrients and the other prepares and provides food. Such an association in which two organisms live together as partners and both the partners are benefited from each other is called symbiosis. Saprophyte is an organism that derives its nutrients from the dead and decaying matter. A parasite is an organism which lives on or in the body of other organism called the host and obtains ready-made food from the host to fulfil its nutrition requirements. In such an association, the host is harmed and the parasite is benefited. An autotroph is an organism that can synthesise its own food from simpler substances.
Hence, the correct answer is option (d).

Answer:

The two raw materials required by plants for photosynthesis are water and carbon dioxide. Plants obtain water from the soil and carbon dioxide from the air.
Hence, the correct answer is option (b).

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In plants, leaves contain a green pigment called chlorophyll. This pigment captures the energy of sunlight which is used to synthesis food in the form of carbohydrates from water and carbon dioxide during photosynthesis. Once the food is synthesised, it is transported to other parts of the plants for its use and storage. So, in plants such as potato and ginger, food is prepared by the leaves present above ground and transported to underground parts for storage.

Answer:

The missing raw materials to the list given below are:
Water, minerals, carbon dioxide, sunlight.
                                    (a)                  (b)
 

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The leaves of a plant synthesise food through photosynthesis for the whole plant. The synthesised food is transported from leaves to other parts for use and storage. So, even if all the leaves of a small plant, balsam, are eaten away by a goat, the plant can survive on the stored food until new leaves sprout in few days and start the synthesis of food through photosynthesis.

Answer:

The unscrambled terms related to modes of nutrition are:
(i) PARASITE
(ii) SAPROPHYTE
(iii) AUTOTROPH
(iv) SYMBIOSIS
 

Answer:

The pulse crops like green gram, Bengal gram, black gram, etc. have a bacterium called Rhizobium in their roots. This bacterium cannot make its food but takes the atmospheric nitrogen and fixes it into the usable form. The bacterium living in the roots of pulse crops supplies this usable form of nitrogen to them and in return, pulse crops provide food and shelter to the bacterium. So, both pulse crops and Rhizobium are benefitted and are in a symbiotic relationship. Such an association of pulse crops with Rhizobium removes their dependency on nitrogen available in the soil thus, farmers do not have to apply nitrogenous fertilisers during the cultivation of pulse crops.

Answer:

The wheat dough has carbohydrates. If it is left open for a few days, saprophytic fungi such as yeast and bread mould will start growing on the wheat dough. During their growth, these saprophytes break down the carbohydrates of wheat dough to obtain their nutrition. The breakdown of carbohydrates results in the emission of foul smell and loss of nutrition value of wheat dough. Thus, the wheat dough becomes spoiled and unfit for use after it is left open for a few days.

Answer:

The raw material(s) essential for photosynthesis that is/are
(a) Available in the plant: Chlorophyll
(b) Available in the soil: Water, minerals
(c) Available in the air: Carbon dioxide
(d) Available during day: Sunlight

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Wild animals like tiger, wolf, lion and leopard are carnivores, that is, they eat the flesh of other organisms. The other organisms may be herbivores or carnivores. Herbivores are plant-eating animals. If there are no plants, herbivores cannot survive. If herbivores are not present, carnivores would also die. So, carnivores are indirectly dependent on plants for their survival. Hence, carnivores cannot survive without plants.

Answer:

Leaves have a green pigment called chlorophyll which captures energy from sunlight. This energy is used in the process of photosynthesis and along with other raw materials like water and carbon dioxide synthesize food.

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The names of the organisms spotted in the given figure are:
Banyan, Rabbit, Mango, Rose, Tiger, Crow, Bhindi, Ginger, Cow, Mushroom, Mice, Fox, Elephant, Bee, Yeast, Carrot, Tulsi, Yam, Owl, Ant, Fish

Classification of these organisms into autotrophs and heterotrophs is:

Answer:

(a) I am tall but I cannot move. I am green and can prepare my own food. tree, autotroph
(b) I live in water; people keep me in an aquarium and feed me. fish, heterotroph
(c) I am small and I can fly. I disturb your sleep, bite you and suck your blood which is my food. mosquito, parasite
(d) I am white and soft. I grow well in the rainy season. Children pluck me from the ground and admire me. I absorb nutrients from decomposed dead parts of plants and animals in the soil. mushroom, saprotroph