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

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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

Aerobic Respiration
- Requires oxygen.
- Glucose is broken down into carbon dioxide and water.
- Provides a significant amount of energy.
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

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