TS 7th Class Science Guide 10th Lesson Nutrition in Plants

TS Board Telangana SCERT 7th Class Science Solutions 10th Lesson Nutrition in Plants Textbook Questions and Answers.

TS 7th Class Science 10th Lesson Questions and Answers Telangana – Nutrition in Plants

Question 1.
A potted plant is kept in light for a day and one of its leaves is tested for starch. The same plant is kept in the dark for two days and another leaf is tested for starch. Will there be any difference in the results of the two experiments? Give reasons for your answer.
Answer:

• When the plant is kept in light for a day, the leaves synthesize sufficient food by the process of photosynthesis.
• Light exposed Leaf ensures the presence of starch (food) in it. We can conclude the presence of starch with iodine test.
• Iodine test on leaf reveals us the photosynthetic rate and the formation of food (starch) by giving blue colour which appears in leaf.
• In contrary, when the same plant is kept in dark place for two days, the occurrence of photosynthesis is completely stopped because there is no exposure of light on leaves.
• Since there is no light, there is no food (starch) formation. As a result, the leaf of dark placed plant doesn’t show blue colour on iodine test.
• We examined the leaves of same plant when it is kept in Light for one day, and in dark place for three days.
• But the final results are in two different ways. One is with light exposed leaves which gives blue colour on iodine test.
• Another one is with dark area leaf which doesn’t give blue colour on iodine test.

Question 2.
What happens if leaves of a green plant are coated with oil? (Hint : What will be the effect on stomata?)
Answer:

• When leaves of a green plant are coated with oil, the stomata present on the surface of leaf will be closed.
• If stomata are closed with any other substance, the exchange of gases will be stopped. the gaseous exchange (oxygen and carbondioxide) will not take place.
• If stomata stops receiving carbondioxide, the photosynthetic rate decreases. As a result, food (starch or carbohydrates) formation stops.
• If there is no sufficient photosynthesis, the leaves release less oxygen to the atmosphere.
• Finally, there will be a decrease of oxygen in the atmosphere. Thus in turn, it affects all the organisms. It will impact on all the organisms.

Question 3.
Do you think saprophytes help us in keeping the environment clean? (Hint: What do saprophytes feed on?)
Answer:

• Saprophytes help us in keeping the environment clean. Most of the bacteria, all fungi come under saprophytes.
• Saprophytes are a type of heterotrophs (Which depend on other organisms for food).
• Some of the bacteria and fungi depend on other dead organisms to obtain nutrients.
• They decompose and degrade the complex molecules present in the dead organisms to simple molecules.
• Bacteria and fungi absorb these molecules through their body surface. Hence they are considered as saprophytes.

Question 4.
Differentiate between the following with some examples.
i. Parasite and Saprophyte
ii. Host and Parasite (Conceptual Understanding)
Answer:
i. Parasite and Saprophyte

Parasite	Saprophyte
1. Organism which lives inside or outside of another organism (host) is called parasite	1. Organisms which live on dead organisms are called saprophytes.
2. Only parasite is benefited	2) Saprophytes add several valuable nutrients to the medium in which they live
3. Body functions of the host are affected badly by the parasite	3. Saprophytes degrade and decompost the dead organism

ii. Host and Parasite

Host	Parasite
1. This is the organism which parasite invades.	1. This is the organism which invades host.
2. Host becomes a site of food for parasite	2. Parasite obtains the nutrients from the host.
3. Host becomes diseased and even die	3. Parasite affects the body of host badly.

Question 5.
Fill in the blanks and give reasons:

i. Lenticels are present on in pLants. (the bark)
Reason: Lenticels are present on the bark of plant through which exchange of air takes place.

ii. The food synthesized by the plants is stored as ‘starch)
Reason: In the plants. glucose is converted into starch for further use.

iii. Saprophytes depend on for food. (dead and decaying organisms)
Reason: They absorb complex molecules and convert into simple molecules.

Question 6.
Name the following.

i. Pores through which leaves exchange gases?
Answer: Stomata.

ii. Plants that act as scavengers of nature.
Answer: Fungi.

iii. Plants that share food and shelter.
Answer: Symbiosis.

iv. Plants that cannot make their own food and obtain it from host.
Answer: Parasitic plants.

Question 7.
Choose the correct answer:

i. Cuscuta is an example of (  )
A) Autotroph
B) Parasite
C) Saprophyte
D) Symbiosis
Answer:
B) Parasite

ii. Haustoria are (  )
A) roots
B) stems
C) leaves
D) All of them
Answer:
A) roots

iii. Raw materials involved in the process of photosynthesis ( )
A) Carbon dioxide
B) Water
C) Sun light
D) All of them
Answer:
D) All of them

Question 8.
Circle the insectivorous plant among the options given below. (Communication through Drawing and Model Making)
(a) Hibiscus
(b) Teak
(c) Nepanthus
(d) Aloevera
Answer:
(c) Nepanthus

Question 9.
Collect information about experiments of Joseph Priestly and Ingenhouz from internet and make a brief note on them.
Answer:
Joseph Priestly:

• Joseph Priestly was a famous biologist who conducted several experiments.
• He carried out a sequence of experiments on exchange of gases between plants and animals.
• He demonstrated that what animals were doing to the air was being reversed by plants.
• He concluded that the animals are making the air impure by releasing carbondioxide. Opposite to the animals, plants are making the air pure by consuming carbondioxide and releasing oxygen in plenty.

Ingenhouz:

• Ingenhouz was the botanist. He tried to repeat Priestley’s experiments under different conditions and found that only the green parts of plants can absorb carhondioxide when they are exposed to the sunlight.
• They prepare food and release oxygen into the air.
• By knowing the experiments of Ingenhouz, we learnt so many evidences.
• We are strongly in belief that plants utilise water from soil, take carbondioxide in the presence of sunlight and they prepare food.

Question 10.
Do you agree with Von Helmont? If nutrients absorbed by plants from soil is equal to the mass of plant tree what will happen ? Think and write your hypothesis.
Answer:

• I do agree with Von Flelmont’s hypothesis because apart from water and soil, there is other intake for the growth of plant and that is carbondioxide.
• According to him, nutrients absorbed by plants from soil is equal to the mass of plant or tree.
• But in early stages, plant is in very less weight.
• As it is growing year by year, it adds weight. Based on the results of Helmont’s experiment, more weight of the plant is seen.
• It showed natural growth irrespective of the consumed weight of the nutrients from the soil.
• Therefore, plant’s growth and their adding weight is not related with mass of the nutrients consumed from the soil.
• The weight of the plant is influenced by some other element apart from soil and water.
• If nutrients absorbed by plants from soil is equal to the mass of plant, the soil will lose its weight. It will affect other plants and animals.

Question 11.
Why are some plants called insectivorous plants ? Give reasons.
Answer:

• A few plants manufacture their own food. But they obtain some nutrients from insects.
• Leaves of these plants are specially modified to trap insects.
• They meet their nitrogen requirements from insects to get free from nitrogen deficiency
• Hence these plants are insectivorous plants. Eg: Droseras, Utricularia, Venusflytrap.

Question 12.
Designery leaves – select any broad leaved potted plant. Cut a card board with a design of your choice and seal the selected leaf with the card board. Let the plant stand under the sun for a week. Then remove the card board. You will get designer leaves plant. ‘fly to make more leaves with designs.
Answer:

Aim : To make a designery leaves from a broad leaved potted plant.
Requirements : Broad leaved potted plant, card boards, blade or knife clips.

Procedure:

• A healthy broad leaved potted plant is taken from the garden.
• A few card boards are designed in star shape and ‘L’ shape with blade or knife.
• These designed card boards are considered as lids.
• These lids act as light screens. Attach the light screens to some leaves.
• The light screens hold the leaves by a lid. Now the lids and light screens have cut designs.
• The plant is kept under the sun for a week. By the end of one week, the card boards are removed.

Observation: It is observed that the cut. design (star or L shaped) on the lid of the light screen appeared on leaves.

Reason: The leaf with light screen receives sunlight on the leaf through the cut design in the lid.

Question 13.
Collect a leaf. Take peels from both sides of the leaf and observe stomata size, shape and number under microscope with the help of your class teacher and write your findings.
Answer:
Aim: To observe stomata size, shape and number appeared on the leaves.

Requirements: A healthy green leaf (piper beetle), coloured nail polish; brush, low power microscope.

Procedure:

• A healthy green leaf (piper beetle) is taken.
• On both the surfaces, coloured nail polish is applied with a brush.
• Now the polish is allowed to dry.
• After complete drying, a peel of polish is taken out (gently) from the margin of the leaf.
• Similarly, peels are taken out from apex and basal side of both surfaces of the leaf.
• Each peel is mounted on a glass slide and observed under microscope.

Observation:

• It is observed that the pattern, frequency and type of distribution of stomata are rather enormous on the lower surface compared to upper surface.
• The size, shape and number of stomata are more on the lower surface.

Question 14.
Prathima said ‘Mushroom is also a p1ant. Is she correct ? How would you support her?
Answer:

• Mushroom is considered as plant organism. They are commonly called fungi.
• They do not contain chlorophyll.
• They are umbrella like structures which grow from the ground.
• They simply absorb organic material usually from the soil.
• These fungi do not depend on other living organisms.
• Since, they are independent of getting food material, they behave like plants.
• Hence, mushroom is a plant.

Question 15.
Photosynthesis is the way plants make food in every leaf by using different items. Write your feelings on this.
Answer:

• Photosynthesis is the basic important life process which is significant on this planet.
• Plants manufacture the food (starch) by utilising raw materials like carbon- dioxide and water by the process of photosynthesis.
• Photosynthesis enables the plants to release oxygen into atmosphere. That oxygen is essential for mankind.
• Photosynthesis helps to purify the atmosphere by absorbing carbondioxide and gives oxygen.
• This life process influences the expansion of the plant population further. It establishes a greater healthy environment.
• Photosynthesis is the only process that utilizes solar energy for synthesizing food.
• Man doesn’t have the capacity of synthesizing food like plants.
• The photosynthesis is a vital living mechanism.
• Leaf supports preparation of lood by receiving sunlight and carbondioxide.

TS 7th Class Science 10th Lesson Notes Nutrition in Plants

• Nutrition : Procurement of nutrients.
• Autotrophs : The organisms which synthesize food on their own.
• Chlorophyll : The leaves contain the green substance, chlorophyll.
• Photosynthesis : Green parts of plants use carbondioxide in the presence of sunlight along with water to make glucose / starch and other food material. This process of making food material is called photosynthesis.
• Stomata : Openings present on surface of leaves.
• Saprophyte : Saprophytes live on decaying organic matter.
• Insectivorous plants : Insectivorous plants fulfill their nitrogen deficiency by trapping insects.
• Carnivorous : The organisms that feed on herbivores.
• Symbiosis : In symbiosis, organisms share their food and shelter.

• Fungi : Lower developed plant organisms.
• In the year 1648, a Belgian scientist Jan Baptista Von Helmont conducted an experiment to show the variation between the weight of the soil and the plant that is grown in the same soil.
• The substances needed for the growth of a plant do not come from the soil only.
• Stephan Hales described the leaves as organs of transpiration.
• The process of loss of excess water from plant body is called transpiration.
• Priest ley carried out a sequence of experiments to demonstrate that what animals were doing to the air was being reversed by plants.
• Ingenhouz tried to repeat priestley’s experiments under different conditions and demonstrated that only green plants receive carbondioxide.
• Carbondioxide + Water Glucose + Oxygen
• Farmers sprinkle urea in rice or wheat fields whenever the leaves turn yellow. The leaves soon become green again.
• Plants that do not photosynthesize, depend on other means for getting their nutrition.