06. Respiration in Organisms Class 7 Science NCERT Notes for Chapter 6 CBSE

Welcome to Respiration in Organisms Class 7 Science NCERT Notes for Chapter 6 CBSE

Respiration in Organisms – Exam Notes

Introduction

• Respiration is a vital biological process for all living organisms, including humans, animals, and plants.
• It involves the exchange of gases, primarily oxygen and carbon dioxide, to produce energy.

Why Do We Respire?

• All living organisms, including humans, respire to obtain energy.
• Energy is released from the breakdown of food.
• Oxygen is essential for this process.
• Breathing is part of respiration and involves inhaling oxygen-rich air and exhaling carbon dioxide.

Types of Respiration

1. Aerobic Respiration
   • Requires oxygen.
   • Glucose is broken down into carbon dioxide and water.
   • Provides a significant amount of energy.
2. Anaerobic Respiration
   • Occurs without oxygen.
   • Glucose is partially broken down into substances like alcohol and carbon dioxide.
   • Provides less energy compared to aerobic respiration.

Anaerobic Respiration in Humans

• Muscle cells can undergo anaerobic respiration during heavy exercise when oxygen supply is limited.
• This can lead to the production of lactic acid, causing muscle cramps.
• Relief from cramps can be achieved through improved blood circulation, which supplies more oxygen.

Breathing

• Breathing is the process of inhaling oxygen and exhaling carbon dioxide.
• It involves the expansion and contraction of the chest cavity and the movement of the diaphragm.
• Breathing rate increases during physical activity to meet the body’s demand for oxygen.

Activity: Measuring Breathing Rate

• An average adult at rest breathes in and out 15–18 times per minute.
• Breathing rate increases during exercise.
• Deep breathing during exercise allows more oxygen intake.

Breathing in Other Animals

• Different animals have various respiratory adaptations:

Humans and Similar Animals

• Humans, cows, dogs, and cats have lungs for respiration.
• They breathe in oxygen and release carbon dioxide.

Insects (e.g., Cockroach)

• Insects have small openings called spiracles.
• Air enters through spiracles and travels through tracheal tubes to reach cells.
• Oxygen diffuses into cells, and carbon dioxide diffuses out.

Earthworm

• Earthworms breathe through their moist skin.
• Oxygen and carbon dioxide exchange occurs through the skin’s surface.

Breathing Underwater

• Some animals like fish have gills for breathing underwater.
• Gills are well supplied with blood vessels for gas exchange.
• Oxygen from water is absorbed through gills, and carbon dioxide is expelled.

Do Plants Also Respire?

• Plants also respire to release energy.
• They take in oxygen through roots and exchange gases through stomata on leaves.
• Oxygen is used to break down glucose into carbon dioxide and water in plant cells.

Conclusion

• Respiration is a fundamental process for all organisms to obtain energy.
• Different organisms have evolved various respiratory adaptations to suit their environments and lifestyles.

Keywords and Definitions

Important definitions for Respiration in Organisms Class 7 chapter 6

• Aerobic Respiration: A type of respiration that requires oxygen and results in the complete breakdown of glucose into carbon dioxide and water, producing energy.
• Anaerobic Respiration: A type of respiration that occurs without oxygen, leading to the partial breakdown of glucose and the production of substances like alcohol and carbon dioxide.
• Breathing Rate: The number of breaths per minute, indicating the rate at which an organism inhales and exhales air.
• Muscle Cells: Cells found in muscles that play a crucial role in movement and can undergo anaerobic respiration during intense exercise.
• Chest Cavity: The space within the chest that houses the lungs and other vital organs involved in respiration.
• Diaphragm: A muscle that separates the chest cavity from the abdominal cavity and aids in the process of breathing.
• Spiracles: Small openings in the exoskeleton of insects that allow air to enter and exit, facilitating respiration.
• Tracheal Tubes: Tubes in the respiratory system of insects that transport air from spiracles to cells for gas exchange.
• Gills: Respiratory organs in aquatic animals, such as fish, specialized for extracting oxygen from water.
• Stomata: Small openings in plant leaves that regulate gas exchange, allowing the plant to take in carbon dioxide and release oxygen.
• Roots: The underground part of a plant that absorbs water and minerals from the soil.

Frequently Asked Questions (FAQs)

FAQs for Respiration in Organisms Class 7

Q1: What is the primary purpose of respiration in living organisms?

A1: The primary purpose of respiration is to obtain energy through the breakdown of food molecules.

Q2: How is aerobic respiration different from anaerobic respiration?

A2: Aerobic respiration requires oxygen and results in the complete breakdown of glucose, while anaerobic respiration occurs without oxygen and leads to partial glucose breakdown.

Q3: Why do muscle cells undergo anaerobic respiration during intense exercise?

A3: Muscle cells undergo anaerobic respiration when oxygen supply is limited during intense exercise, leading to the production of lactic acid.

Q4: What is the function of spiracles in insects?

A4: Spiracles are small openings that allow air to enter and exit an insect’s body, facilitating gas exchange in their tracheal tubes.

Q5: How do fish respire underwater?

A5: Fish respire underwater through gills, specialized organs that extract oxygen from water and release carbon dioxide.

Q6: Do plants also respire?

A6: Yes, plants also respire to release energy. They take in oxygen through their roots and exchange gases through stomata on leaves.

Q7: What is the role of the diaphragm in the process of breathing?

A7: The diaphragm is a muscle that contracts and relaxes, causing changes in chest volume, which aids in the inhalation and exhalation of air.

Q8: Can aerobic respiration occur in the absence of oxygen?

A8: No, aerobic respiration requires oxygen for the complete breakdown of glucose. Without oxygen, anaerobic respiration occurs.

Q9: How do earthworms respire?

A9: Earthworms respire through their moist skin, where gas exchange, including the intake of oxygen and release of carbon dioxide, occurs.

Q10: Why is deep breathing recommended during exercise?

A10: Deep breathing during exercise allows for increased oxygen intake, meeting the body’s heightened demand for oxygen during physical activity.

This was the end of Respiration in Organisms Class 7 Science NCERT Notes for Chapter 6 CBSE

For more information, refer to NCERT SOLUTIONS, NCERT NOTES, and NCERT BOOKS .