1. Introduction to Respiration

Respiration is the process by which plants break down food (glucose) to release energy for life activities.

Plants make food by photosynthesis, but they also need energy to:

Grow
Absorb water and minerals
Repair tissues
Transport substances

This energy is obtained through respiration.

2. Definition of Respiration

Respiration is the chemical process in which glucose reacts with oxygen to release energy, carbon dioxide, and water.

Word Equation


\text{Glucose + Oxygen → Carbon dioxide + Water + Energy}

Energy released is used by the plant for its activities.

3. Parts of Plants that Respire

Respiration occurs in all living parts of plants, such as:

Roots
Stems
Leaves
Flowers
Fruits
Seeds

Unlike photosynthesis, respiration occurs in every living cell.

4. Exchange of Gases in Plants

Plants exchange gases with the environment through different structures.

1. Stomata

Found on leaves.
Allow oxygen to enter and carbon dioxide to exit.

2. Lenticels

Small pores found on stems.
Help in gas exchange in woody plants.

3. Root Hairs

Roots take oxygen from the air spaces in the soil.

5. Types of Respiration

There are two types of respiration.

1. Aerobic Respiration

Respiration that occurs in the presence of oxygen.

Characteristics

Oxygen is required
Produces more energy
Produces carbon dioxide and water

Example:

Most plants and animals perform aerobic respiration.

2. Anaerobic Respiration

Respiration that occurs without oxygen.

Characteristics

Oxygen not required
Less energy produced
Produces alcohol or lactic acid

Example:

Yeast during fermentation

6. Respiration vs Photosynthesis

Photosynthesis	Respiration
Produces food	Breaks down food
Occurs only in green parts	Occurs in all cells
Needs sunlight	Occurs day and night
Uses carbon dioxide	Produces carbon dioxide
Releases oxygen	Uses oxygen

7. Importance of Respiration in Plants

Respiration is essential because it:

1. Releases Energy

Energy is needed for plant growth and development.

2. Helps in Growth

Cells divide and enlarge using energy.

3. Helps Absorption

Roots absorb water and minerals using energy.

4. Helps Transport of Food

Energy is needed to move food inside the plant.

8. Experiment to Show Respiration in Plants

Experiment with Germinating Seeds

Steps:

Take some germinating seeds in a flask.
Close the flask with a cork and connect a tube to limewater.
After some time, limewater turns milky.

Conclusion

Carbon dioxide is produced during respiration.

9. Key Terms

Term	Meaning
Respiration	Process of releasing energy from food
Aerobic respiration	Respiration with oxygen
Anaerobic respiration	Respiration without oxygen
Stomata	Tiny pores on leaves
Lenticels	Small openings on stems

10. Short Summary

Respiration in plants is the process by which plants break down food to release energy. It occurs in all living cells of the plant and continues day and night. Plants take in oxygen and release carbon dioxide during respiration.

✅ If you want, I can also provide:

Difference between respiration in plants and animals
Labelled diagrams for ICSE exams
Important exam questions from this chapter
A longer 3000–4000 word chapter for revision.

Respiration in Plants (Class 7 Level Notes)
Respiration is an important life process in all living organisms, including plants. Through respiration, plants release energy from food to perform different life activities.

What is Respiration?
Respiration is the process by which living cells break down food (glucose) in the presence of oxygen to release energy.
The energy released is used for:
Growth
Repair of tissues
Transport of materials
Formation of new cells
Basic Equation of Respiration
Glucose + Oxygen → Carbon dioxide + Water + Energy
This energy is used by the plant for various metabolic activities.
Difference Between Respiration and Photosynthesis
Respiration
Photosynthesis
Breaks down food
Makes food
Occurs in all living cells
Occurs only in green cells
Requires oxygen
Uses carbon dioxide
Releases energy
Stores energy
Occurs day and night
Occurs only in sunlight
Where Does Respiration Occur in Plants?
Respiration occurs in all parts of the plant, including:
Roots
Stems
Leaves
Flowers
Fruits
Seeds
Every living plant cell performs respiration.
Types of Respiration in Plants
Plants carry out two types of respiration.
Aerobic Respiration
This type of respiration occurs in the presence of oxygen.
Glucose + Oxygen → Carbon dioxide + Water + Energy
Characteristics:
Produces a large amount of energy
Occurs in most plant cells
Anaerobic Respiration
This respiration occurs in the absence of oxygen.
Glucose → Alcohol + Carbon dioxide + Energy
Characteristics:
Produces less energy
Occurs in some microorganisms like yeast
Also called fermentation
Respiration in Different Parts of Plants
Respiration in Roots
Roots take oxygen from the air present in the soil spaces.
The oxygen diffuses into the root cells and carbon dioxide diffuses out.
Respiration in Stems
In woody stems, respiration occurs through small openings called lenticels.
Lenticels allow exchange of gases between the stem and the atmosphere.
Respiration in Leaves
Leaves exchange gases through small pores called stomata.
Stomata help in:
Respiration
Photosynthesis
Transpiration
Process of Respiration in Plants
Respiration occurs in two main stages.
Glycolysis
Glucose is broken down into smaller molecules and energy is released.
Cellular Respiration
The smaller molecules are further broken down in the presence of oxygen to release energy.
Energy Produced During Respiration
Energy released during respiration is stored in a molecule called ATP (Adenosine Triphosphate).
ATP is called the energy currency of the cell because it supplies energy for various cellular activities.
Factors Affecting Respiration in Plants
Several factors affect the rate of respiration.
Temperature
Higher temperature increases respiration up to a certain limit.
Oxygen availability
More oxygen increases respiration.
Water content
Water is necessary for respiration.
Age of plant tissues
Young tissues respire faster than older tissues.
Importance of Respiration in Plants
Respiration is important because it:
Releases energy for growth
Helps in the absorption of minerals
Supports cell division
Helps in the synthesis of important substances
Maintains plant metabolism
Without respiration, plants cannot survive.
Differences Between Plant and Animal Respiration
Plant Respiration
Animal Respiration
No specialized organs
Specialized organs like lungs
Gas exchange through stomata and lenticels
Gas exchange through lungs
Slower process
Faster process
Interesting Facts About Plant Respiration
Plants respire all the time, day and night.
Respiration occurs in mitochondria, the powerhouses of the cell.
Growing parts of plants respire faster.
Seeds also respire during germination.
Summary
Respiration in plants is the process through which food is broken down to release energy. This energy is necessary for growth, development, and maintenance of life processes.
Plants exchange gases through stomata, lenticels, and root hairs, and respiration occurs in all living cells of the plant.
If you want, I can also provide:
Very long 4000–5000 word ICSE notes on respiration in plants
Labelled diagram of stomata and plant respiration
50 MCQs from this chapter
Short and long exam questions for Class 7 ICSE.

Respiration in Plants – Detailed Notes (Class 7 ICSE)

Introduction
All living organisms need energy to perform life processes such as growth, reproduction, repair, and movement of substances. Plants obtain this energy through the process of respiration.
In plants, the food produced during photosynthesis (mainly glucose) is broken down to release energy. This process is called respiration.
Respiration occurs continuously in all living cells of the plant, both during the day and night.
Definition of Respiration
Respiration is the process by which food substances are broken down in cells to release energy.
The energy released during respiration is used for:
Growth of plant tissues
Transport of water and minerals
Formation of new cells
Germination of seeds
Repair of damaged parts
Chemical Equation of Respiration
The overall chemical equation of respiration is:
Glucose + Oxygen → Carbon dioxide + Water + Energy
In scientific form:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy
Site of Respiration in Plant Cells
Respiration occurs in a special cell organelle called the mitochondria.
Mitochondria are often called the powerhouse of the cell because they release energy during respiration.
However, the first stage of respiration occurs in the cytoplasm of the cell.
Stages of Respiration
Respiration takes place in several stages.
Glycolysis
Occurs in the cytoplasm
Glucose is broken down into smaller molecules called pyruvate
A small amount of energy is released
Krebs Cycle
Occurs inside the mitochondria
Pyruvate is further broken down
Carbon dioxide is released
More energy is produced
Electron Transport Chain
Final stage of respiration
Large amount of energy is released
Water is formed
Types of Respiration in Plants
Plants can perform two types of respiration.
Aerobic Respiration
This respiration takes place in the presence of oxygen.
Glucose + Oxygen → Carbon dioxide + Water + Energy
Characteristics:
Produces a large amount of energy
Occurs in most plant cells
More efficient process
Anaerobic Respiration
This respiration occurs without oxygen.
Glucose → Alcohol + Carbon dioxide + Energy
Characteristics:
Produces less energy
Occurs in yeast and some microorganisms
Also called fermentation
Gas Exchange in Plants
Plants exchange gases with the environment for respiration.
Different plant parts exchange gases in different ways.
Stomata
Stomata are small pores present on the surface of leaves.
Functions of stomata:
Exchange of oxygen and carbon dioxide
Release of water vapour (transpiration)
Help in photosynthesis
Lenticels
Lenticels are small openings present in the bark of woody stems.
Functions:
Allow gas exchange between stem tissues and the atmosphere.
Root Hairs
Roots absorb oxygen from air spaces present in the soil.
Oxygen diffuses into the root cells and carbon dioxide diffuses out.
Respiration in Different Plant Parts
Respiration in Leaves
Leaves respire through stomata.
Respiration in Stems
Stems exchange gases through lenticels.
Respiration in Roots
Roots take oxygen from the air spaces between soil particles.
Energy Released in Respiration
The energy released during respiration is stored in a molecule called ATP (Adenosine Triphosphate).
ATP stores energy and supplies it to the cell when needed.
Functions of ATP:
Provides energy for growth
Helps in synthesis of molecules
Supports transport processes in cells
Factors Affecting Respiration
The rate of respiration in plants depends on several factors.
Temperature
Higher temperature increases respiration rate up to an optimum level.
Oxygen Supply
More oxygen increases aerobic respiration.
Water Content
Water is necessary for metabolic reactions.
Age of Plant Tissue
Young tissues respire faster than old tissues.
Importance of Respiration in Plants
Respiration is very important for plants because it:
Provides energy for growth
Helps in cell division
Supports absorption of minerals
Helps in transport of substances
Maintains metabolic activities
Without respiration, plants cannot survive.
Respiration vs Photosynthesis
Feature
Respiration
Photosynthesis
Purpose
Releases energy
Produces food
Gas used
Oxygen
Carbon dioxide
Gas released
Carbon dioxide
Oxygen
Time
Day and night
Only in sunlight
Site
Mitochondria
Chloroplast
Respiration in Germinating Seeds
When seeds begin to germinate, respiration increases greatly.
Reasons:
Seeds need energy for growth
Cell division occurs rapidly
Stored food is broken down
This is why germinating seeds produce heat.
Importance of Oxygen in Soil
Plants require oxygen in soil for root respiration.
If soil becomes waterlogged, oxygen supply decreases and roots may suffocate.
This can lead to poor plant growth.
Interesting Facts About Plant Respiration
Plants respire continuously day and night.
Growing tissues respire faster.
Germinating seeds release heat energy.
Even stored fruits and vegetables continue to respire.
Summary
Respiration in plants is the process by which food is broken down to release energy. This energy supports all vital activities of the plant.
Respiration occurs in all living plant cells, mainly in the mitochondria, and involves the breakdown of glucose using oxygen.
Plants exchange gases through stomata, lenticels, and root hairs, ensuring a continuous supply of oxygen and removal of carbon dioxide.
If you want, I can also provide:
Labelled diagram of stomata and respiration in plants
50–100 MCQs for ICSE exams
Short and long exam questions
One-page quick revision sheet for this chapter.

Respiration in Plants – Extended Notes (Class 7 ICSE)

Life Processes in Plants
Plants perform several life processes to survive, such as:
Photosynthesis
Respiration
Transpiration
Growth
Reproduction
Among these processes, respiration is essential because it provides the energy required for all other activities.
Relationship Between Photosynthesis and Respiration
Photosynthesis and respiration are closely related processes.
During photosynthesis, plants produce food (glucose).
During respiration, this food is broken down to release energy.
Relationship
Photosynthesis
Respiration
Stores energy
Releases energy
Occurs in chloroplast
Occurs in mitochondria
Uses carbon dioxide
Produces carbon dioxide
Produces oxygen
Uses oxygen
Thus, both processes maintain the balance of oxygen and carbon dioxide in nature.
Diffusion of Gases in Plants
Plants do not have specialized breathing organs like animals. Instead, gases move in and out of plant tissues by diffusion.
Diffusion is the movement of gases from a region of higher concentration to a region of lower concentration.
For example:
Oxygen diffuses into plant cells.
Carbon dioxide diffuses out of plant cells.
Respiration in Seeds
Seeds also perform respiration, especially during germination.
During germination:
Stored food in the seed is broken down.
Energy is released for growth of the embryo.
Oxygen is required.
Experiments show that germinating seeds release carbon dioxide and heat.
Respiration in Stored Food
Even after harvesting, plant products like fruits and vegetables continue to respire.
Because of this:
They slowly lose freshness.
They may become soft or spoiled.
To slow down respiration, food is often stored in refrigerators where the temperature is low.
Measurement of Respiration Rate
Scientists measure the rate of respiration by observing:
Amount of oxygen used
Amount of carbon dioxide produced
Amount of heat released
Higher respiration rate means the plant cells are more active.
Importance of Soil Aeration
Roots need oxygen for respiration.
Soil must contain air spaces so that oxygen can reach the roots.
Farmers improve soil aeration by:
Ploughing the soil
Loosening the soil
Avoiding waterlogging
Proper aeration helps roots respire efficiently.
Respiration and Energy Use in Plants
Energy released during respiration is used for:
Growth of roots, stems, and leaves
Cell division
Transport of minerals
Production of flowers and fruits
Repair of damaged tissues
Without energy from respiration, plants cannot grow or reproduce.
Differences Between Aerobic and Anaerobic Respiration
Feature
Aerobic Respiration
Anaerobic Respiration
Oxygen
Required
Not required
Energy produced
Large amount
Small amount
End products
Carbon dioxide and water
Alcohol and carbon dioxide
Occurrence
Most plant cells
Yeast and some microbes
Respiration and Heat Production
Respiration releases heat energy along with chemical energy.
Examples:
Germinating seeds release heat.
Compost heaps become warm due to respiration of microorganisms.
This heat helps maintain suitable conditions for biological processes.
Experiments Showing Respiration in Plants
Experiment with Germinating Seeds
Materials:
Germinating seeds
Lime water
Glass flask
Observation:
Carbon dioxide released by seeds turns lime water milky.
Conclusion:
Seeds respire and release carbon dioxide.
Importance of Respiration in Agriculture
Respiration affects crop production.
Farmers manage conditions to maintain proper respiration by:
Maintaining soil aeration
Controlling water supply
Maintaining suitable temperature
Proper respiration ensures healthy plant growth and higher yield.
Common Misconceptions
Some people think plants only produce oxygen.
However, plants both produce and use oxygen.
During photosynthesis, oxygen is produced.
During respiration, oxygen is used.
Respiration occurs all the time, even when photosynthesis is not occurring.
Interesting Facts About Plant Respiration
Respiration occurs 24 hours a day in plants.
Germinating seeds have very high respiration rates.
Fruits and vegetables continue to respire after harvest.
Plant cells use ATP as their main energy source.
Quick Revision Points
Respiration is the breakdown of food to release energy.
It occurs in all living plant cells.
Oxygen is required for aerobic respiration.
Plants exchange gases through stomata, lenticels, and roots.
Energy released during respiration is stored in ATP.
If you want, I can also give:
Labelled diagrams of stomata and plant respiration
50–100 MCQs from this chapter
Important short answer questions
Long answer exam questions for ICSE
One-page quick revision notes for fast study.

Respiration in Plants – Very Detailed Study Notes (Class 7 ICSE)

1. Meaning of Respiration

Respiration is the biochemical process by which living cells break down food molecules to release energy. In plants, the food used for respiration is mainly glucose, which is produced during photosynthesis.

The energy released during respiration is essential for performing many life activities such as:

Growth of plant tissues
Transport of water and minerals
Synthesis of new molecules
Repair of damaged cells
Germination of seeds

Thus, respiration is necessary for the survival of plants.

2. Chemical Reaction of Respiration

The chemical reaction for respiration is:

Glucose + Oxygen → Carbon dioxide + Water + Energy

In chemical form:

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy

The energy released is stored in the form of ATP molecules.

3. Role of Glucose in Respiration

Glucose is the main fuel used during respiration.

Source of glucose:

Produced during photosynthesis
Stored in plants as starch
Converted back to glucose when needed

During respiration, glucose molecules are broken down step by step to release energy.

4. Cellular Respiration

Respiration that occurs inside the cells is called cellular respiration.

This process occurs mainly in the mitochondria, which are tiny organelles present in plant cells.

Mitochondria are often called the powerhouses of the cell because they generate energy.

5. Stages of Cellular Respiration

Cellular respiration occurs in several stages.

Glycolysis

Occurs in the cytoplasm
Glucose is broken into smaller molecules
A small amount of energy is released

Krebs Cycle

Occurs in the mitochondria
Carbon dioxide is produced
Energy molecules are formed

Electron Transport System

Final stage of respiration
Produces a large amount of ATP
Water is formed

6. Respiration in Various Plant Tissues

Respiration occurs in all living tissues of plants.

Leaves

Leaves exchange gases through stomata.

Oxygen enters the leaf and carbon dioxide leaves during respiration.

Stems

In young stems, gas exchange occurs through stomata.

In woody stems, gas exchange occurs through lenticels.

Roots

Roots take oxygen from air spaces in the soil.

Root hairs absorb oxygen needed for respiration.

7. Role of Stomata in Respiration

Stomata are small pores on the surface of leaves.

Each stoma is surrounded by guard cells.

Functions of stomata:

Allow entry of oxygen
Allow exit of carbon dioxide
Help regulate water loss through transpiration

Stomata open and close depending on environmental conditions.

8. Role of Lenticels

Lenticels are small openings found in the bark of woody plants.

Functions:

Allow gas exchange between internal tissues and the atmosphere.
Help in respiration of woody stems.

9. Respiration in Germinating Seeds

During germination, seeds require a large amount of energy.

Therefore, the rate of respiration increases.

The stored food inside the seed is broken down to supply energy for:

Growth of the embryo
Development of roots and shoots

This is why germinating seeds release heat and carbon dioxide.

10. Role of Oxygen in Respiration

Oxygen is essential for aerobic respiration.

Functions of oxygen:

Helps break down glucose completely
Produces more energy
Removes hydrogen atoms during respiration

If oxygen is not available, plants may switch to anaerobic respiration, which produces less energy.

11. Respiration in Fruits and Vegetables

After harvesting, fruits and vegetables continue to respire.

Effects of respiration after harvest:

Gradual loss of freshness
Softening of fruits
Spoilage over time

To reduce respiration rate, fruits are often stored in cold storage.

12. Respiration and Growth

Respiration provides energy required for plant growth.

Energy is required for:

Cell division
Cell elongation
Tissue formation
Development of flowers and fruits

Without respiration, plants cannot grow or reproduce.

13. Environmental Factors Affecting Respiration

Several environmental factors influence respiration.

Temperature

Respiration increases with temperature up to an optimum limit.

Oxygen Availability

Adequate oxygen increases respiration efficiency.

Water Supply

Water is necessary for metabolic reactions.

Age of Tissue

Young tissues have higher respiration rates.

14. Agricultural Importance of Respiration

Respiration is important in agriculture because it affects:

Crop growth
Seed germination
Storage of fruits and vegetables

Farmers manage environmental conditions to maintain proper respiration rates.

15. Summary of Respiration in Plants

Respiration is a vital life process in plants. It involves the breakdown of glucose to release energy necessary for growth and survival.

Respiration occurs in all living plant cells and mainly takes place in the mitochondria.

Plants exchange gases through stomata, lenticels, and roots, allowing oxygen to enter and carbon dioxide to leave.

The energy released during respiration is stored in ATP, which powers various cellular activities.

If you want, I can also give you these very useful exam materials for Class 7 ICSE:

Labelled diagrams (stomata and plant respiration)
100 MCQs from respiration in plants
Important short answer questions
Long answer exam questions
One-page quick revision sheet for fast study.

Respiration in Plants – Complete Study Notes (Class 7 ICSE)

1. Overview of Respiration in Plants

Respiration is a continuous process that occurs in all living cells of plants. It is the process through which plants break down food (glucose) to release energy. This energy is necessary for all biological activities of the plant.

Plants prepare their food during photosynthesis, but the energy stored in this food cannot be used directly. Therefore, the plant cells break down glucose during respiration to release usable energy.

Respiration takes place day and night, whereas photosynthesis occurs only in the presence of sunlight.

2. Basic Steps of Respiration

The respiration process in plants can be summarized in three main steps.

Step 1: Intake of Oxygen

Oxygen from the surrounding air enters plant cells through different openings such as stomata, lenticels, and root hairs.

Step 2: Breakdown of Food

Inside the cells, glucose molecules are broken down through several chemical reactions.

This process releases:

Carbon dioxide
Water
Energy

Step 3: Release of Waste Products

The waste products formed during respiration leave the plant:

Carbon dioxide diffuses out through stomata and lenticels.
Water may evaporate through transpiration.

3. Exchange of Gases in Plants

Plants exchange gases mainly through three structures.

Stomata

Stomata are microscopic pores present on the surface of leaves.

Functions:

Allow oxygen to enter the plant.
Allow carbon dioxide to exit.
Help regulate water loss.

Stomata are controlled by guard cells which open and close the pore.

Lenticels

Lenticels are small pores found in the bark of woody stems.

Functions:

Permit gas exchange between internal tissues and the outside environment.
Help stems carry out respiration.

Root Hairs

Root hairs absorb oxygen present in the air spaces between soil particles.

If soil lacks oxygen, roots cannot respire properly.

4. Energy Currency of Cells (ATP)

During respiration, energy is released in the form of ATP (Adenosine Triphosphate).

ATP is called the energy currency of the cell because:

It stores chemical energy.
It releases energy when needed.
It powers cellular activities.

Examples of activities requiring ATP:

Transport of substances
Growth of cells
Production of enzymes
Cell division

5. Differences Between Plant Respiration and Animal Respiration

Feature	Plant Respiration	Animal Respiration
Organs	No special organs	Special organs like lungs
Gas exchange	Through stomata, lenticels, roots	Through lungs or gills
Rate	Slower	Faster
Energy demand	Lower	Higher

6. Respiration During Germination

Germination is the process by which a seed develops into a new plant.

During germination:

Stored food in the seed is used.
Respiration rate increases.
Energy is released for growth.

Germinating seeds require:

Oxygen
Water
Suitable temperature

7. Effect of Temperature on Respiration

Temperature affects enzyme activity in respiration.

At low temperatures, respiration slows down.
At optimum temperature, respiration occurs efficiently.
At very high temperatures, enzymes may get damaged and respiration slows.

This is why plants grow best at suitable temperatures.

8. Effect of Oxygen on Respiration

Oxygen is necessary for aerobic respiration.

If oxygen supply decreases:

Plants may perform anaerobic respiration.
Less energy is produced.

Poor oxygen supply may occur in waterlogged soil.

9. Storage of Agricultural Products

Respiration continues even after harvesting crops.

To prevent spoilage:

Fruits and vegetables are stored in cool environments.
Cold temperatures slow down respiration.

This increases the shelf life of food products.

10. Importance of Respiration in Ecosystem

Respiration plays an important role in the ecosystem.

It helps in:

Releasing carbon dioxide into the atmosphere
Maintaining the carbon cycle
Supporting life processes of plants

Thus, respiration and photosynthesis together maintain balance in nature.

11. Experiments Demonstrating Respiration in Plants

One common experiment involves germinating seeds and lime water.

Observation:

Lime water turns milky.

Reason:

Carbon dioxide released during respiration reacts with lime water.

This proves that plants release carbon dioxide during respiration.

12. Key Points for Quick Revision

Respiration is the breakdown of food to release energy.
It occurs in all living cells of plants.
It mainly takes place in the mitochondria.
Plants exchange gases through stomata, lenticels, and roots.
Energy released during respiration is stored as ATP.
Respiration occurs both day and night.

If you want, I can also provide these very helpful ICSE exam materials:

✅ Labelled diagram of stomata (important for exams)
✅ 50–100 MCQs from respiration in plants
✅ Important short answer questions
✅ Long answer exam questions
✅ One-page super fast revision sheet.

Respiration in Plants – Additional Advanced Notes (Class 7 ICSE)

1. Why Respiration is Necessary for Plants

Plants need energy for many activities even though they do not move like animals. Energy from respiration is required for:

Growth of roots, stems, and leaves
Absorption of water and minerals from the soil
Transport of food inside the plant
Formation of flowers, fruits, and seeds
Repair of damaged tissues

Without respiration, plants would not be able to carry out these important life processes.

2. Respiration and Plant Growth

Young and actively growing plant parts respire faster than older parts.

Examples of tissues with high respiration rate:

Growing root tips
Young leaves
Developing fruits
Germinating seeds

These parts require more energy, so respiration occurs more rapidly in them.

3. Respiration in Different Environmental Conditions

Effect of Light

Respiration occurs both in light and in darkness.

However, during the daytime both photosynthesis and respiration occur together.

At night only respiration takes place.

Effect of Water

Water is necessary for the chemical reactions involved in respiration.

If a plant does not receive enough water:

Metabolic activities slow down
Respiration rate decreases
Growth becomes poor

Effect of Food Supply

Respiration requires food such as glucose.

If a plant does not produce enough food through photosynthesis, the respiration rate may decrease because less fuel is available.

4. Respiration in Aquatic Plants

Aquatic plants also respire.

Examples include plants living in ponds, lakes, and rivers.

These plants obtain oxygen from:

Oxygen dissolved in water
Air spaces within their tissues

Some aquatic plants have special structures that help transport gases inside the plant.

5. Respiration in Desert Plants

Desert plants adapt to harsh conditions.

Characteristics related to respiration:

Reduced leaf surface area
Thick cuticle
Fewer stomata

These adaptations help conserve water while still allowing respiration.

6. Role of Enzymes in Respiration

Respiration is controlled by enzymes.

Enzymes are special proteins that:

Speed up chemical reactions
Help break down glucose
Control different stages of respiration

Without enzymes, respiration reactions would occur very slowly.

7. Respiration and the Carbon Cycle

Respiration plays an important role in the carbon cycle.

Steps involved:

Plants take in carbon dioxide during photosynthesis.
They convert carbon dioxide into glucose.
During respiration, glucose is broken down.
Carbon dioxide is released back into the atmosphere.

This continuous cycle helps maintain the balance of carbon in nature.

8. Comparison of Respiration in Plants and Animals

Feature	Plants	Animals
Special organs	No specialized organs	Lungs, gills, etc.
Rate of respiration	Slower	Faster
Gas exchange	Through stomata, lenticels, roots	Through respiratory organs
Energy requirement	Lower	Higher

9. Importance of Respiration in Agriculture

Farmers consider respiration while growing crops.

Important practices include:

Ploughing soil to improve oxygen supply
Avoiding waterlogging
Maintaining proper temperature
Providing nutrients

These practices help plants respire efficiently and grow well.

10. Storage of Fruits and Vegetables

Respiration continues after harvesting fruits and vegetables.

If respiration occurs rapidly:

Fruits ripen quickly
Food spoils faster

To slow respiration:

Food is stored in cool temperatures
Refrigeration is used
Controlled atmosphere storage may be used

11. Interesting Facts About Plant Respiration

Plants respire 24 hours a day.
The energy released during respiration is stored in ATP molecules.
Germinating seeds produce heat due to respiration.
Fruits and vegetables continue to respire even after harvesting.

12. Final Summary

Respiration in plants is the process through which food is broken down to release energy required for growth and survival. It occurs in all living cells of the plant and mainly takes place in the mitochondria.

Plants exchange gases through stomata, lenticels, and roots. The energy released during respiration is stored as ATP, which powers various biological activities.

Respiration is essential for plant growth, reproduction, and maintenance of life processes.

If you want, I can also prepare these exam-focused materials for Class 7 ICSE:

Labelled diagrams of stomata and respiration in plants
100 MCQs with answers
Important short answer questions
Long answer questions for exams
1-page quick revision sheet (very useful before exams).

Respiration in Plants – Additional Deep Notes (Class 7 ICSE)

1. Cellular Energy and ATP

During respiration, the energy released from glucose is stored in ATP (Adenosine Triphosphate).

ATP is important because:

It stores energy temporarily.
It releases energy when a phosphate bond breaks.
Cells use this energy to perform activities.

Examples of processes that use ATP:

Active transport of minerals in roots
Synthesis of proteins
Cell division and growth
Movement of substances inside cells

Because ATP provides energy for cellular activities, it is often called the energy currency of the cell.

2. Role of Mitochondria in Respiration

The mitochondria are small rod-shaped organelles found in plant cells.

Functions of mitochondria:

Site of cellular respiration
Production of ATP
Breakdown of glucose molecules

Each mitochondrion contains enzymes that help perform different stages of respiration.

Cells that require more energy usually contain more mitochondria.

3. Respiration and Transport in Plants

Respiration provides energy for transport of substances in plants.

Energy is required for:

Absorption of minerals by roots
Transport of water through the xylem
Movement of food through the phloem

Without respiration, plants cannot transport essential substances throughout their bodies.

4. Respiration and Mineral Absorption

Roots absorb minerals from the soil through a process called active transport.

Active transport requires energy from respiration.

Minerals absorbed by roots include:

Nitrogen
Phosphorus
Potassium
Calcium
Magnesium

These minerals are essential for plant growth and development.

5. Respiration in Storage Organs

Some plants store food in special organs.

Examples:

Potato (tuber)
Carrot (root)
Onion (bulb)
Ginger (rhizome)

Even though these organs store food, they are living tissues and continue to respire.

During respiration, stored food may slowly be used up.

6. Relationship Between Respiration and Transpiration

Respiration and transpiration are different processes but they are connected.

Transpiration helps maintain water movement in plants, while respiration provides the energy required for metabolic activities.

Both processes often occur through the stomata of leaves.

7. Respiration and Ripening of Fruits

Respiration plays a major role in fruit ripening.

During ripening:

Respiration rate increases.
Starches convert into sugars.
Fruits become softer and sweeter.

Examples of fruits that ripen after harvesting:

Bananas
Mangoes
Apples

This increase in respiration during ripening is called the respiratory climacteric.

8. Respiration in Microorganisms Associated with Plants

Microorganisms living in soil also perform respiration.

Examples include:

Bacteria
Fungi

These microorganisms break down organic matter in soil, releasing nutrients that plants can absorb.

Thus, respiration of soil organisms contributes to soil fertility.

9. Adaptations for Respiration in Plants

Plants have different adaptations to ensure proper respiration.

Aquatic Plants

Have air-filled tissues that help transport oxygen.

Desert Plants

Have fewer stomata to reduce water loss but still allow gas exchange.

Mangrove Plants

Have special breathing roots called pneumatophores that grow above water to obtain oxygen.

10. Experimental Evidence of Respiration in Plants

Scientists use different experiments to prove respiration in plants.

Experiment Using Lime Water

Germinating seeds are placed in a flask connected to a tube containing lime water.

Observation:

Lime water turns milky.

Explanation:

Carbon dioxide released during respiration reacts with lime water to form calcium carbonate.

11. Importance of Respiration in Ecosystem

Respiration plays an important role in maintaining ecosystem balance.

It helps:

Release carbon dioxide for photosynthesis
Maintain the carbon cycle
Provide energy for plant life

Thus, respiration supports the flow of energy in ecosystems.

12. Final Conclusion

Respiration in plants is a vital biological process through which stored food is broken down to release energy. This energy powers various plant activities such as growth, absorption of nutrients, and reproduction.

Respiration occurs in all living plant cells and mainly takes place in the mitochondria. Plants exchange gases through stomata, lenticels, and roots, ensuring a continuous supply of oxygen and removal of carbon dioxide.

Without respiration, plants would not be able to perform essential life processes and survive.

If you want, I can also prepare extra useful exam materials for you:

📘 100–150 MCQs from Respiration in Plants
📘 Important short and long exam questions
📘 Labelled diagrams of stomata and respiration process
📘 1-page quick revision sheet for exams.