🌱 Chapter Introduction
Plants are living organisms and, just like animals, they carry out several essential life processes. They need food, water, gases and minerals to grow, develop and survive.
Plants have special structures and processes that help them obtain nutrients, exchange gases, transport substances and remove wastes. Understanding these processes helps us appreciate how plants survive even though they cannot move from place to place like animals.
🌿 1. What Are Life Processes in Plants?
Life processes are essential activities that living organisms perform to stay alive, grow and maintain their bodies.
Photosynthesis
Green plants prepare food using light energy, carbon dioxide and water.
Respiration
Plants release usable energy from food through respiration.
Transportation
Water, minerals and food are transported to different parts of the plant.
Growth
Plants grow and develop by producing new cells and tissues.
🍃 2. Nutrition in Plants
Green plants are generally called autotrophs because they can prepare their own food from simple substances.
Plants mainly use carbon dioxide from the air and water absorbed from the soil to prepare food using light energy.
Why do plants need food?
- For growth and development.
- To produce new cells and tissues.
- To obtain energy through respiration.
- To repair and maintain plant structures.
☀️ 3. Photosynthesis
Photosynthesis is one of the most important processes carried out by green plants. During photosynthesis, plants use light energy to prepare food.
Materials needed for photosynthesis
Sunlight
Provides the energy required for photosynthesis.
Carbon Dioxide
Enters the leaf from the surrounding air.
Water
Is absorbed from the soil through the roots.
Chlorophyll
The green pigment that helps leaves capture light energy.
🧪 4. Simple Representation of Photosynthesis
Photosynthesis can be represented in a simple form as:
↓
Light Energy + Chlorophyll
↓
Food (Glucose) + Oxygen
The food produced can be used by the plant or converted into substances such as starch for storage.
🍃 5. Why Are Leaves Called Food Factories?
Leaves are often called the food factories of plants because photosynthesis mainly takes place in green leaves.
Leaves contain chlorophyll, which captures light energy required for photosynthesis.
Important functions of leaves
- They carry out photosynthesis.
- They exchange gases with the surrounding air.
- They lose water vapour through transpiration.
🔬 6. Stomata
Tiny openings found mainly on the surfaces of leaves are called stomata.
Stomata help in the exchange of gases between the leaf and the surrounding atmosphere. They also play an important role in the loss of water vapour.
🌱 7. Roots and Absorption of Water
Roots anchor the plant in the soil and also help absorb water and minerals.
Root hairs
Fine structures called root hairs increase the surface area of roots and help them absorb water and minerals from the soil.
💧 8. Transportation in Plants
Plants need a system for transporting water, minerals and food to different parts of the plant.
Two important conducting tissues are xylem and phloem.
Xylem
Xylem transports water and minerals mainly from the roots towards the stem and leaves.
Phloem
Phloem transports food made by the leaves to other parts of the plant.
🔍 9. Xylem and Phloem
| Xylem | Phloem |
|---|---|
| Transports water and minerals. | Transports food made by the plant. |
| Water generally moves from roots towards aerial parts. | Food is transported from source tissues to parts where it is needed or stored. |
| Important for supplying water to leaves. | Important for distributing food throughout the plant. |
💨 10. Transpiration
Plants lose water in the form of water vapour, mainly through stomata in their leaves. This process is called transpiration.
Why is transpiration important?
- It contributes to the movement of water through the plant.
- It helps in the transport of water and minerals from roots.
- It contributes to cooling of plant surfaces.
🫁 11. Respiration in Plants
Plants also need energy for growth, repair, transport and other cellular activities. This energy is obtained through respiration.
Respiration takes place in living cells of plants.
☀️ 12. Photosynthesis vs Respiration
| Photosynthesis | Respiration |
|---|---|
| Prepares food in green plants. | Releases usable energy from food. |
| Uses carbon dioxide and water. | In aerobic respiration, oxygen is involved. |
| Requires light energy. | Does not require sunlight directly. |
| Oxygen is produced as a product of photosynthesis. | Carbon dioxide and water are produced in aerobic respiration. |
🌬️ 13. Gas Exchange in Plants
Plants exchange gases with their surroundings. Leaves have stomata that provide pathways for gas exchange.
During photosynthesis, carbon dioxide enters the leaf and oxygen is released. During respiration, oxygen is used and carbon dioxide is produced.
During Photosynthesis
Carbon dioxide is used and oxygen is released.
During Respiration
Oxygen is used and carbon dioxide is produced.
🌳 14. How Different Plant Parts Help
| Plant Part | Important Functions |
|---|---|
| Roots | Anchor the plant and absorb water and minerals. |
| Stem | Supports the plant and helps transport substances. |
| Leaves | Carry out photosynthesis, gas exchange and transpiration. |
| Flowers | Help in reproduction in flowering plants. |
🪴 15. Minerals Needed by Plants
Plants require several minerals in small or larger quantities for healthy growth and development.
Roots absorb mineral nutrients from the soil along with water. These nutrients are transported to different parts of the plant.
Why are minerals important?
- They support healthy plant growth.
- They are required for various biochemical processes.
- They help plants develop properly.
- Different minerals have different roles in plant nutrition.
🔗 16. How Life Processes in Plants Work Together
Plant life processes are closely connected. Each process supports other processes in maintaining the plant.
🌿 17. Life Processes Around Us
We can observe evidence of plant life processes in everyday life.
- A plant kept in sunlight grows and develops leaves.
- Water supplied to the soil eventually reaches different parts of the plant.
- Leaves exchange gases with the surrounding atmosphere.
- Plants lose water vapour, especially on warm days.
- Plants continue to respire even when there is no sunlight.
⚡ Chapter 10 Quick Revision
- Plants are living organisms and carry out several essential life processes.
- Green plants are generally autotrophic because they prepare their own food.
- Photosynthesis uses carbon dioxide, water and light energy in the presence of chlorophyll.
- Leaves are the main sites of photosynthesis in most plants.
- Stomata help in gas exchange and water loss through transpiration.
- Roots absorb water and minerals from the soil.
- Xylem transports water and minerals through the plant.
- Phloem transports food from leaves to other parts of the plant.
- Transpiration is the loss of water vapour from aerial parts of plants.
- Plants respire continuously and release energy from food.
- Photosynthesis and respiration are different processes but are closely connected.
- Different plant parts work together to keep the plant alive and growing.
📖 Important Terms
✏️ Important Practice Questions
1. What are life processes?
Life processes are essential activities performed by living organisms to survive, grow and maintain their bodies.
2. Why are green plants called autotrophs?
Green plants are called autotrophs because they can prepare their own food from simpler substances using light energy.
3. What is photosynthesis?
Photosynthesis is the process by which green plants use light energy to prepare food from carbon dioxide and water in the presence of chlorophyll.
4. What is the role of chlorophyll?
Chlorophyll is a green pigment that helps plants capture light energy needed for photosynthesis.
5. What are stomata?
Stomata are tiny pores, mainly found on leaves, that help in gas exchange and the loss of water vapour.
6. What is the function of roots?
Roots anchor the plant and absorb water and minerals from the soil.
7. What is the function of xylem?
Xylem transports water and minerals from the roots towards different parts of the plant.
8. What is the function of phloem?
Phloem transports food produced by the leaves to other parts of the plant.
9. What is transpiration?
Transpiration is the loss of water vapour from the aerial parts of a plant, especially through stomata.
10. Do plants respire at night?
Yes. Plant cells respire continuously, including during the night. Respiration does not require sunlight directly.
🤔 Think & Explore
❓ Frequently Asked Questions
What is Chapter 10 of Class 7 Science?
Chapter 10 of Class 7 Science is titled Life Processes in Plants.
What are the main topics in Life Processes in Plants?
The chapter deals with important plant processes such as nutrition, photosynthesis, respiration, transportation, gas exchange and transpiration.
Why are leaves called food factories?
Leaves are called food factories because photosynthesis, through which green plants prepare food, mainly takes place in leaves.
What is the function of xylem?
Xylem transports water and minerals from the roots to other parts of the plant.
What is the function of phloem?
Phloem transports food produced in leaves to other parts of the plant.
Do plants respire during the night?
Yes. Plants respire continuously, during both day and night.
What is transpiration?
Transpiration is the loss of water vapour from the aerial parts of plants, mainly through stomata.