Class 7 Science Chapter 10 Assignment - Nutrition in Plants

Multiple Choice Questions (MCQs)

Q1: What is the process through which plants make their own food?
(a) Respiration
(b) Photosynthesis
(c) Transpiration
(d) Germination
Ans:  (b) Photosynthesis
Photosynthesis is the process by which plants make their own food using sunlight, carbon dioxide, and water.

Q2: Which part of the plant absorbs carbon dioxide for photosynthesis?
(a) Roots
(b) Stomata
(c) Flowers
(d) Petals
Ans:  (b) Stomata
Stomata are tiny pores present on the surface of leaves that allow the absorption of carbon dioxide for photosynthesis.

Q3: What is the main product of photosynthesis?
(a) Oxygen
(b) Glucose
(c) Nitrogen
(d) Water
Ans:  (b) Glucose
The main product of photosynthesis is glucose, a carbohydrate that plants use for energy and growth.

Q4: Which of the following is an example of a parasitic plant?
(a) Rose
(b) Cuscuta
(c) Mango tree
(d) Pea plant
Ans:  (b) Cuscuta
Cuscuta is a parasitic plant that derives nutrients from the host plant as it lacks chlorophyll.

Q5: What is the function of chlorophyll in plants?
(a) Absorbs water
(b) Absorbs sunlight
(c) Absorbs carbon dioxide
(d) Breaks down starch
Ans:  (b) Absorbs sunlight
Chlorophyll is a green pigment that absorbs sunlight, which is used for photosynthesis in plants.

Short Question/Answer (Q&A)

Q1: What are autotrophs?
Ans:  Autotrophs are organisms that can make their own food using simple substances like water, carbon dioxide, and minerals. Plants are autotrophs because they carry out photosynthesis.

Q2: Why can’t humans make their own food like plants?
Ans:  Humans cannot make their own food because they lack the ability to perform photosynthesis. Instead, they depend on plants or animals for food.

Q3: What is the role of stomata in plants?
Ans:  Stomata are tiny pores on the surface of leaves that allow the plant to take in carbon dioxide from the air and release oxygen during photosynthesis.

Q4: What is the importance of photosynthesis for life on Earth?
Ans:  Photosynthesis is crucial because it produces food for plants and releases oxygen, which is essential for the survival of most living organisms on Earth.

Q5: How do plants obtain nitrogen for making proteins?
Ans:  Plants obtain nitrogen from the soil, where certain bacteria convert atmospheric nitrogen into a usable form. Plants absorb this nitrogen to make proteins and other nutrients.

Activity-Based Questions

Q1. Perform an iodine test on the leaves of two potted plants, one kept in the dark and the other in sunlight.
Ans: Iodine test

• Dark Plant: The plant kept in the dark will not show starch after the iodine test, indicating that photosynthesis did not occur due to the lack of light.

• Sunlight Plant: The plant kept in sunlight will show the presence of starch after the iodine test, confirming that photosynthesis occurred, and starch was produced as a result of light energy.

Conclusion: This experiment demonstrates that photosynthesis requires light to produce starch in plants.

Q2. Observe fungi growth on moistened bread.
Ans:  Fungi growth on moistened bread: 

Moist and Warm Conditions: After keeping the bread in a moist, warm environment for 2-3 days, observe the cotton-like growth of fungi on the surface.

Fungal Growth: This growth is due to fungi absorbing nutrients from the decaying bread, showing their saprotrophic mode of nutrition where they feed on decomposing organic matter.

Conclusion: The experiment illustrates how fungi thrive on decaying organic material, highlighting their role in nutrient recycling in nature.

Research-Based Question

Q1. Research the different types of nutrition found in plants and how they affect plant survival.
Ans:  Different types of nutrition are: 

1. Autotrophic Nutrition:

• Plants like green plants use photosynthesis to produce their own food. They convert sunlight, carbon dioxide, and water into glucose and oxygen.

• This mode of nutrition is crucial for plant survival because it allows plants to create their own energy source, enabling them to thrive in a variety of environments.

2. Parasitic Nutrition:

• Some plants, like Cuscuta (dodder), have a parasitic relationship with other plants. They attach themselves to a host plant and absorb nutrients directly from it, often harming the host plant in the process.

• This mode of nutrition is beneficial in low-nutrient environments, where the plant cannot produce its own food.

3. Saprotrophic Nutrition:

• Plants like fungi (mushrooms, molds) are saprotrophs. They break down dead organic matter and absorb nutrients from it.

• This form of nutrition is vital for decomposing organic material, recycling nutrients, and helping plants survive in environments where organic matter is abundant.

Conclusion: These different types of nutrition allow plants to adapt and survive in various environments by obtaining nutrients in diverse ways, whether through self-production, parasitism, or decomposition.

​Guessing Game!

Instructions: I will describe something related to plant nutrition, and you need to guess what it is! Let's see how many you can get right!

1. I am the process that happens in a plant's leaves, where sunlight is used to create food, and oxygen is released. I am crucial for the plant’s survival and growth. What am I?
Ans: Photosynthesis

2. You can find me in the green parts of plants, and I help in absorbing sunlight. Without me, the plant wouldn't be able to perform the process that produces its food. Who am I?

Ans: Chlorophyll

3. I do not make my own food, but I attach myself to a plant and take nutrients from it. I harm my host while gaining all I need to survive. What am I?

Ans: Cuscuta (a parasitic plant)

4. I am the place in the plant where most of the food-making process happens. I am green, flat, and have a large surface area to catch sunlight. What am I?

Ans: Leaf

5. I’m not always visible, but I am always happening in the leaves of plants. I help in water movement and cooling, and I am crucial for maintaining the plant’s water balance. What am I?

Ans: Transpiration

6. I thrive on decaying organic material and play a key role in breaking down dead things. I don't make my own food from sunlight, but instead absorb nutrients from the decay around me. What am I?

Ans: Fungi

7. I am the way some plants get their food by breaking down dead and decaying matter, not through the soil. I help in recycling nutrients and keeping the environment clean. Who am I?

Ans: Saprotrophic plants (like mushrooms or fungi)

Crossword Puzzle

Ans:  

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