Respiration in Organisms: Breathing Life into Cells

NCERT’s Grade 7 Science chapter 10, titled “Respiration in Organisms,” delves deep into the life-sustaining process of respiration. As we unravel the mysteries of this crucial biological process, we’ll comprehend how organisms, from the smallest bacteria to the largest mammals, extract energy to thrive.

What is Respiration?

Respiration is the process by which organisms take in oxygen from the environment and release carbon dioxide. This process allows cells to produce energy, essential for various life processes.

Breathing vs. Respiration

Though often used interchangeably, breathing and respiration are distinct:

• Breathing: The physical act of taking in oxygen and expelling carbon dioxide.
• Respiration: A chemical reaction where glucose reacts with oxygen to produce energy, carbon dioxide, and water.

Aerobic and Anaerobic Respiration

• Aerobic Respiration: Takes place in the presence of oxygen. It’s the most efficient form of respiration, producing more energy.
  • Equation: Glucose + Oxygen -> Carbon dioxide + Water + Energy
• Anaerobic Respiration: Occurs without oxygen. It’s less efficient, producing lesser energy and sometimes producing lactic acid or alcohol.
  • Equation (in muscles): Glucose -> Lactic acid + Energy
  • Equation (in yeast): Glucose -> Alcohol + Carbon dioxide + Energy

Human Respiratory System

The main components include:

• Nasal Cavity: Filters, moistens, and warms incoming air.
• Trachea: Transports air to and from the lungs.
• Bronchi and Bronchioles: Distribute air within the lungs.
• Lungs: Main respiratory organs where gas exchange occurs.
• Alveoli: Tiny sacs in lungs where oxygen is exchanged for carbon dioxide.

Breathing Mechanism

Breathing consists of two main phases:

1. Inhalation: Intercostal muscles and diaphragm contract, increasing lung volume and drawing in air.
2. Exhalation: Intercostal muscles and diaphragm relax, decreasing lung volume and pushing out air.

Respiration in Other Organisms

• Plants: Plants respire too! They take in oxygen through stomata and tiny pores in roots, using it to break down glucose.
• Aquatic Animals: Fish use gills to extract oxygen from water. Some aquatic insects breathe through spiracles.
• Insects: They have a network of air tubes called tracheae for gas exchange.
• Amphibians: Frogs respire through their moist skin and lungs.

Adaptations in Respiration

Different organisms have evolved various adaptations:

• Camels: Nasal passages adapted to conserve water during exhalation.
• Dolphins: Blowholes on top of their heads allow them to breathe without fully surfacing.
• Birds: Air sacs ensure a continuous supply of fresh air during both inhalation and exhalation.

Significance of Respiration

Respiration powers life. From running and playing to growth and repair, all life processes need the energy generated from respiration.

Conclusion: The Breath of Life

Chapter 10 of NCERT’s Grade 7 Science offers a holistic view of the intricate dance of molecules that powers life. Respiration, in all its forms and variations, highlights the beauty of life’s interconnectedness. As we inhale and exhale, we partake in the rhythm of existence, underscoring the marvel that is the science of life.

---