Class 4 | Crystal Curated Grade 4 | Semester 1 | Science | Lesson 1. Plants: Preparing and Storing Food.

New Words

* transpiration: release of water in the form of vapor from plant leaves

* by-product: some that are produced in the  process of making something else; here, oxygen is released as a by-product of photosynthesis

* glucose: a simple sugar that is stored in large quantities in the stems, leaves, and roots of some plants

* conserve: to protect something of environmental importance from harm.

* wildlife sanctuary: it is a place that provides protection for wildlife from hunting and capturing

* deforestation: clearing of a forest or trees.

Recap

* The presence of a substance called chlorophyll makes a leaf appear green.

* Leaf blade, apex, petiole, midrib and side veins are part of a leaf.

* Plants need three basic things, such as carbon dioxide, water and sunlight to make food.

* The process by which green plants prepare food for their own is called photosynthesis.

* During photosynthesis, green leaves prepare their food. This food is produced in the form of glucose and stored in the form of starch in leaves, fruits, seeds, and stems of plants.

* Insectivorous plants such as Venus Flytrap, sundews, and pitcher plants derive their food from trapping and consuming insects.

* Plants are the primary source of food for animals.

Exercise

A. Choose the correct answer.

1. Which of the following is known as the 'food factory' of a plant?

Ans: b) Leaf

2. ____ is the form in which plants make food.

Ans: b) Glucose

3. Which of the following by-product of photosynthesis is used by humans to breathe?

Ans: c) Oxygen

4. ____ obtains food from dead and decaying plants and animals.

Ans: a) Fungus

5. ____ plants trap the energy of sun to prepare food.

Ans: b) Green

B. Fill in the blanks.

1. Main vein performs the transportation of _____, water and food to the leaf.

Ans: minerals

2. Programmes like ____ promote the planting of trees.

Ans: Van Mahostav

3. The leaves of a plant kept in dark do not produce ____.

Ans: food

4. ____ of the cactus plant prepares food.

Ans: The thick, fleshy green stems

5. Extra food is stored in the form of ____ in the leaves, stems. or roots.

Ans: starch

C. Give one word for the following:

1. Name of the plant that does not have leaves.

Ans: Cactus

2. Pores on the underside of the leaf.

Ans: Stomata

3. A substance that makes the leaves appear green.

Ans: Chlorophyll

4. The main vein running along the center.

Ans: Midrib

5. Food prepared by the plant is in the form of.

Ans: Glucose

6. The World Environment Day is observed on.

Ans: 5th June

D. Answer the following questions. Short answer questions.

1. Provide the names of the different parts of a leaf?

Ans: The names of the different parts of a leaf are leaf blade or lamina, Apex, Petiole, Midrib or main vein and side veins.

2.What is chlorophyll? Explain its significance in plants.

Ans: Chlorophyll is a green-colored substance found in the leaves of a green plant. Chlorophyll makes a leaf green. It further helps green leaves to make food for the plant. Its presence helps green leaves to trap sunlight.

3. Define the term 'photosynthesis'?

Ans: The presence of chlorophyll helps green leaves to trap sunlight. Green leaves use this sunlight to prepare food from water and carbon dioxide and water. Since this entire process takes place in the presence of sunlight. So, it is called photosynthesis.

(photo+synthesis = light + putting together)

4. What are insectivorous plants?

Ans: Insectivorous plants are the plants that derive some or most of their food from trapping and consuming insects and other small animals.

5. What are Fungi? Give two examples.

Ans:  Fungi are non-green plants that do not contain chlorophyll unlike green plants.

         Two examples are moulds and mushrooms.

Long answer questions:

1. Write a short note on functions of a leaf?

Ans: The leaves of a tree are considered to be one of the main components of a plant. It has various functions.

        Those are as follows :

* It prepares food for the plant by a process known as photosynthesis. Therefore, it is called a plant's kitchen or the food factory of a plant.

* It is a site, where transpiration of water takes place.

* It helps a plant to perform gaseous exchange through stomata. The air that plants breathe in is carbon dioxide, whereas the air that plants release is oxygen.

2. What are the functions of stomata?

Ans: Pores on the underside of the leaf are called stomata. It has mainly three functions-

* It regulates gas exchange between the plant and environment.

* It controls of water loss by changing the size of the stomatal pore.

* It takes in carbon dioxide and gives out oxygen during the process of photosynthesis.

* It helps in removing water from the leaves.

3. Explain the process by which leaves make food for plants.

Ans: The process by which green plants prepare food for their own is called photosynthesis.

        During photosynthesis, green leaves prepare its food. This food is produced in the form of glucose and stored in the form of starch in leaves, fruit, seeds and stem of plants.

4. Carbon dioxide is necessary for the plants to prepare food. Prove this statement with the help of an example.

Ans: Carbon dioxide is necessary for the plants to prepare food. With an example, we can prove the statements.

        First of all, choose a green leaf of a potted plant. Now place the plant in the open for 3-5days. Test the leaf for starch. Also test another leaf of the same potted plant for starch. If you notice, then you will find that the covered part of the leaf turned blue black on the addition of iodine solution. It tells us that the statement is justified.

5. Describe how plants use the food made by leaves. What happens to the extra food?

Ans: The food prepared by plants is available in the form of simple sugar, that is, glucose. Plants use it to obtain energy for the growth and development of plants.

        The extra food is stored as starch in the leaves, roots, fruits and seeds of a plant. The starch stored in them is used as food sources for humans and some animals too.

6. Explain how a pitcher plant obtains its food.

Ans: In a pitcher plant, the leaf is shaped like a pitcher with a small lid. The pitcher of the plant has a deep cavity that is filled with a digestive fluid. Insects such as

flies get attracted to the brightly coloured pitcher and sits on it. Then the lid of the pitcher closes, thus trapping the insect. The digestive fluid inside the cavity digests the insects.

7. How are plants and animals interdependent on each other? Justify this statement with the help of an example.

Ans: Plants and animals are interdependent on each other for many things.

* In a natural environment, plants are the primary source of food for animals. Since animals cannot make their own food, they are entirely dependent on plants and/or other animals for their survival.

* Plants release oxygen as a by-product during photosynthesis. This oxygen is necessary for our survival.

* Plants also provide shelter for animals and birds.

* Plants help to regulate the levels of carbon dioxide and oxygen present in the air.