Std 7 Science Chapter : Plants: Structure and Function

Title : Std 7 Science Chapter : Plants: Structure and Function

INDEX I. Nutrition II. Autotrophic plants III. Transport system in plants IV. Biological fixation of nitrogen V. Symbiotic nutrition VI. Heterotrophic plants VII. Insectivorous plants VIII. Saprophytic plants IX. Nutrition in animals X. Types of nutrition in animal

Maharashtra state board solutions for class 7 SSC board science part STD 7-  science Plants: Structure and Function


 Know everything about Plants: Structure and Function Maharashtra state board class 7 SSC .Get detailed Questions and answers for chapter Science . Nutrition II. Autotrophic plants III. Transport system in plants IV. Biological fixation of nitrogen V. Symbiotic nutrition VI. Heterotrophic plants VII. Insectivorous plants VIII. Saprophytic plants IX. Nutrition in animals X. Types of nutrition in animal


*Q.1) What is malnutrition?

 Answer: Lack of proper nutrition, caused by not having enough to eat, not eating enough of the right things, or being unable to use the food that one does eat.

*Q.2) Which are the ways to prevent malnutrition?

Answer: Encourage healthier food choices. Snacking on healthy foods is a good way to get extra nutrients and calories between meals. Make food taste good again. Consider adding supplements to your loved one's diet. Encourage exercise. Plan social activities.


**Q.2) Give the classification of nutrients.

Answer: We get several types of nutrients from foodstuffs. Nutrients can be classified into two types, namely, macro-nutrients and micro nutrients.

**Q.5) Define nutrition

. Answer: The process of taking in and using food, which takes place in living organisms is called nutrition.

*Q.7) What is autotrophic nutrition?

Answer: Some organisms can produce their own food and thus nourish themselves. This is called autotrophic nutrition.

*Q.8) What is heterotrophic nutrition?

 Answer: Some organisms depend on other organisms, plants or animals, for their food. This is called heterotrophic nutrition.

Autotrophic plants

*Q.1) How do plants produce their food?

 Answer: Plants also need food for their growth. They can produce their own food. With the help of sunlight and chlorophyll, plants make their food in their leaves, using water and nutrients from the soil and carbon dioxide from the air. This process is called as photosynthesis.

 **Q.2) Give the chemical reaction of photosynthesis.

Answer: Carbon dioxide + water Sunlight Food (glucose) + oxygen 6CO2 + 6H2O Chlorophyll C6H12O + 6O

Q.4) Write the role of chloroplast in photosynthesis

. Answer: Water, minerals and salts are absorbed by roots from the soil. The stem transports them up to the leaves. The leaves have microscopic openings called stomata. through which they take in the CO2 from the air. The chloroplasts present in the leaves contain chlorophyll, which absorbs sunlight, helping to convert carbon dioxide and water into food. Oxygen is given out in this process.

Transport system in plants

 **Q.1) Write about the transport system in plants

. Answer: The transport system of plants consists of the xylem and the phloem. The xylem transports minerals and water from the root to all aerial parts of the plant. The phloem transports the food (glucose, etc.) from the leaves to other parts of the plant where it is either consumed or stored. Though the plants have a transport system, they do not have a separate digestive or excretory system.

 *Q.2) What is chemosynthesis? Which plants produce their food by chemosynthesis?

Answer: Some rare autotrophs produce food through a process called chemosynthesis, rather than through photosynthesis. Autotrophs that perform chemosynthesis do not use energy from the sun to produce food. Instead, they make food using energy from chemical reactions, often combining hydrogen sulfide or methane with oxygen.

Biological fixation of nitrogen

Q.2) Write a note on atmospheric nitrogen fixation.

 Answer: Atmospheric fixation of nitrogen: Lightning (thunderbolts) occur in the rainy season. This causes atmospheric nitrogen and oxygen to react with each other to form nitric oxide (NO2) which is again oxidized to form nitrogen dioxide (NO2). The nitrogen dioxide dissolves in rainwater and is converted into nitric acid (HNO3) which gets added to the soil along with the rain-water. Plants use this nitrogen for their growth.

Symbiotic nutrition

**Q.2) Give an example of symbiotic nutrition.

Answer: Some fungi grow around the roots of some other plants. These plants supply nutrients to the fungi and in turn, fungi supply minerals and water to the plants. Some fungi and algae live together. The fungi provide water, minerals as well as shelter to algae. In return, the algae provide food to the fungi. Lichen is an example of a symbiosis between algae and fungi.

Heterotrophic plants

*Q.1) Heterotrophic plants do not contain chlorophyll. How do the heterotrophic plants live? From where do they get food?

 Answer: The plants that grow on the body of other plants to obtain food are called as parasitic plants, for example, loranthus, cuscuta, etc. Due to the absence of chlorophyll, the cuscuta is completely dependent on the host plant. Hence, it is said to be a completely parasitic plant

.2) Have you seen a yellow, wire-like, leafless climber plant growing on a big tree? What is its name? Answer: Cuscuta is a dodder plant. This parasite produces yellow tubular structures which attach themselves to a plant and wrap them around the stem and branches. It is leaves are reduced to minute scales. Chlorophyll is not present in this plant. It absorbs ready-made food from the host plant on which it climbs through special structures called as haustoria. These haustoria absorb food from the host plant

Insectivorous plants

 **Q.1) What do you mean by insectivorous plants?

Answer: Some plants feed upon insects to obtain nutrients. These insectivorous plants generally grow in soil or water deficient in nitrogen compounds. The plant body of the Drosera burmanii has a flower- like appearance. It grows close to the ground. Its leaves are attractively pink or red in colour with hairs at the margin. Droplets of a sticky substance found at the tips of the hairs attract insects. The scientist Johannes Burman identified this plant in Sri Lanka in 1737. Hence, the plant is named after him.

Saprophytic plants

Q.2) Why does food gets spoiled?

 Answer: Food gets spoiled due to some fungi. Some fungi cause diseases or illness while some fungi have medicinal properties. Yeast and some mushrooms are useful. Yeast is used in fermentation processes and for making bread. Mushrooms are a rich source of iron and vitamins

Types of nutrition in animals

*Q.1) How does ingestion occur in unicellular animals like Amoeba?

 Answer: Amoeba does not have organs like hands and mouth. It is a unicellular animal. It can take in food through any part of the surface of its unicellular body. It surrounds the food particle from all sides to take it into the cell. After that, it digests the food with the help of different  enzymes. Undigested food is left behind as the amoeba moves further with the help of pseudopodia. In unicellular animals like amoeba, euglena, paramoecium, etc. all the steps of nutrition occur within their unicellular body.

Q.9) Where are anteaters found?

 Answer: The anteater is found in Central and South America.

*Q.11) What are bobcat?

Answer: The bobcat or udmanjar is an ant- eating animal found in India.

*Q.13) Have you seen small animals on the bodies of animals like dogs and buffaloes? Which are those small animals?

Answer: Gnats or some other parasitic animals are found on animals like buffaloes and dogs. *Q.14) From where do these little animals obtain their food? Answer: They suck blood from the host on which they live.

 *Q.15) From where do the worms in the intestine obtain their food?

 Answer: By sucking the nutrients from inside the intestines of the host which are being digested in them, the worms in the intestine obtain their food.

**Q.16) What is parasitic nutrition?

Answer: Some animals depend upon other animals for food. They can obtain the food only from animals on whom they are dependent. This is call

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