Nutrition in Plants- 3 - Free MCQ Practice Test with solutions, Class 7

- P - Carbon dioxide is essential for photosynthesis to take place.
- This statement is true. Carbon dioxide is one of the reactants needed for photosynthesis to occur in plants.
- Q - The products of photosynthesis are simple sugars.
- This statement is true. The main products of photosynthesis are simple sugars, such as glucose, that provide energy for the plant.
- R - Photosynthesis occurs in the green leaves of plants.
- This statement is true. Photosynthesis primarily takes place in the chloroplasts of the green leaves of plants, where chlorophyll captures sunlight energy.
- S - Sunlight is not used as an energy source by plants to make food during photosynthesis.
- This statement is false. Sunlight is a crucial energy source for plants during photosynthesis. It is absorbed by chlorophyll and used to convert carbon dioxide and water into glucose and oxygen.
So option D is correct
Topic in NCERT: NUTRITION IN PLANTS
Line in NCERT: "Chlorophyll, water, carbon dioxide and sunlight are the essential requirements for photosynthesis." "The product of photosynthesis is not a protein." "Solar energy is absorbed by the chlorophylls present in leaves/plants." "During the process oxygen is released."

In the given equation, X represents carbon dioxide and Y represents oxygen.
The reaction of photosynthesis:
carbon dioxide + water → (energy from light, chlorophyll in leaves) glucose + oxygen
Chemical equation:
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

The cell membrane, also known as the plasma membrane, is a thin, flexible outer boundary that encloses the contents of a cell. It acts as a protective barrier, regulating the movement of substances in and out of the cell. The cell membrane is composed mainly of a double layer of phospholipids, with proteins embedded within it. These proteins help in various functions, such as transporting molecules, cell signaling, and providing structural support.

The membrane is selectively permeable, meaning it allows certain molecules, like oxygen, nutrients, and waste products, to pass through while blocking others. This control is essential for maintaining the cell's internal environment and supporting life processes.

Symbiosis refers to a close and long-term relationship between two different organisms in which both organisms benefit from the association. The characteristic feature of symbiosis is that the organisms live together and derive mutual benefits. There are different types of symbiotic relationships:

1. Mutualism: Both organisms benefit (e.g., bees and flowers — bees get nectar, and flowers get pollinated).
2. Commensalism: One organism benefits, and the other is neither helped nor harmed (e.g., barnacles on a whale).
3. Parasitism: One organism benefits at the expense of the other (e.g., ticks on mammals).

However, in true symbiosis (specifically mutualism), both organisms get something positive from the relationship, making Option C the correct answer.

• Light from the sun is the primary energy source for biological systems.
• Plants capture sunlight through photosynthesis, converting it into chemical energy stored in carbohydrates.
• These carbohydrates serve as food for other organisms, creating a food chain.
• Thus, all life ultimately relies on solar energy, making it the foundation of energy input in ecosystems.

Topic in NCERT: NUTRITION IN PLANTS

Line in NCERT: "The solar energy is captured by the leaves and stored in the plant in the form of food. Thus, sun is the ultimate source of energy for all living organisms."

Most CO₂ reach the photosynthesising cells of green leaves through diffusion. Stomata (tiny pores) present of leaf surface and stem facilitates gaseous exchange between the plant cells and the surrounding. CO₂ move into the cells through these small pores.