Nutrition In Plants

Science Class Seven

Questions of Boojho and Paheli

Question (1) Boojho wants to know how plants prepare their own food?

Answer:

Plants prepare their food using the process of Photosynthesis.

Photosynthesis takes place in the leaves of green plants.

Chlorophyll present in green leaves absorbs energy from sunlight, carbon dioxide from air and water from soil and synthesis food.

Question (2) Paheli wants to know why our body cannot make food from carbon dioxide, water and minerals like plants do?

Answer

Chlorophyll, sunlight, carbon dioxide and water are the necessary components for photosynthesis to be taken place. In the case of absence of anyone of these, photosynthesis is not possible.

Since, our body do not have chlorophyll including other necessary mechanism for photosynthesis, so our body do not synthesise food like plants do.

Question (3) Boojho wants to know how water and minerals absorebed by roots reach the leaves?

Answer:

Plants have a system of hair like capillaries in their stems. These capillaries are called xylem.

Plants absorb water and minerals from roots and transport them to the leaves and other parts of plants through these capillaries known as xylem.

Question (4) Paheli wants to know what is so special about the leaves that they can synthesise food but other parts of the plant cannot?

Answer

In the leaves of plants a chemical named chlorophyll is found. The green colour of leaves is due to the presence of chlorophyll in them. There are many small pores found on the lower surface of leaves which are called stomata.

Leaves absorb energy from sunlight usingchlrophyll and carbon dioxide from air through stomata and water and other minerals from soil.

After getting carbon dioxide, water and other minerals in the presence of sunlight and chlorophyll, leaves synthesise food. The food making process of plants is called photosynthesis.

Since, food is synthesise in leaves of the plants, so leave is called Kitchen of plants.

Since chlorophyll is not present in other parts of plants, such as stem, so photosynthesis does not take place in other parts of plants.

Question (5) Boojho has observed some plants with deep red, violet or brown leaves. He wants to know whether these leaves also carry out photosynthesis?

Answer : Leaves having deep red, violet or brown also have chlorophyll present in them. But these colours overlap the green colour of chlorophyll, so green colour is not seen in such leaves.

Since, these other colour leaves such as deep red, violet or brown also have chlorophyll present in them, thus photosynthesis takes place in these leaves also.

Question (6) Palheli wants to know whether mosquitoes, bed bugs, lice and leeches that suck our blood are also parasites?

Answer

Organisms which feed on other organisms are called parasites.

Since, mosquitoes, bed bugs, lice and leeches feed on other animals by sucking their blood, to these are also parasites.

Question (7) Boojho is confused. If the pitcher plant is green and carries out photosynthesis, then why does it feed on insects?

Answer

Soil in which plants like pitcher plants grow is deficient in some nutrients so pithcher plants could not get all required nutrients from soild.

Thus, pitcher plants eat insects to fulfill the requirement of those nutrients which they not get from soil in which they grow.

Question (8) Boojho wants to know how these organisms acquire nutrients. They do not have mouths like animals do. They are not like green plants as they lack chlorophyll and cannot make food by photosynthesis.

Answer

The question of Boojho is about saprotrophs.

The mode of nutrition is different in saprotrophs.

Saprotrophs do not have mouth similar to animals neither have chlorophyll similar to leaves.

Saprotrophs feed on dead and decaying organisms.

Saprotrophs secrete digestive juice over the dead and decaying animas and convert it into a solution. Then they absorb the nutrients from it. This mode of nutrition is called saprotrophic mode of nutrition. Mushroom is an example of saprotrophs.

Question (9) Paheli is keen to know whether her beautiful shoes, which she wore on special occasions, were spoiled by fungi during the rainy season. She wants to know how fungi appear suddenly during the rainy season.

Answer

The spores of fungi are generally present in air. When they alnd on wet and warm things they germinate and grow.

The weather in rainy season is moist and humid which is most suitable to germinate and grow for fungi. So, these fungi grow in rainy season and spoil the things on which they grow.

Question (10) Boojho says once his grandfather told him that his wheat fields were spoiled by a fungus. He wants to know if fungi cause diseases also.

Answer

Fungi feeds on other organisms on which they germinate and grow. To get nutrients fungi secretes digestive juice on organism which they grow and converts it into a solution. Then they absorb nutrients from it. During getting nutrients fungi decompose the organisms on which they grow. This is the cause that fungi are called natural decomposer.

Sometimes fungi germinate and grow on wheat, rice and other plants and spoled them to get nutrients. This is called fungal disease.

Thus, fungi causes disease also.

Question (11) Paheli told him that many fungi like yeast and mushrooms are useful, but some fungi cause diseases in plants, animals and humans. Some fungi are also used in medicines.

Answer

Useful fungii

Yeast and mushrooms are useful fungi.

Yeast is used in fermentation of doe used for making bread, cake, and used for fermentation of fruit juice to make wine, bear, soy sauce, etc.

Mushroom which is a fungi is used as vegetable.

Fungi which causes for diseases

Some fungi spoiled the plants after germinate and growing over them. Some fungi are cause for skin disease in animals. For example ringworm is a fungal skin disease. Dandruff is also a fungal disease.

Fungi used as medicine

Some fungi are used to make antibiotics. Since fungi are natural decomposer thus, some fungi are used in making weedicides which control unwanted plants in field.

7-science-home


Reference: