Respiration-in-Organisms-Class-7-NCERT.pptx

Respiration in plants and animals

1. Respiration in Organisms: Class 7 NCERT Exploring the vital process of how living beings derive energy.

2. Why Do We Respire? The Need for Energy All living organisms require energy for their survival and daily activities. From growth and repair to movement and reproduction, every cellular function demands a constant supply of energy. Respiration is the fundamental process that liberates this energy from food. 1 Growth & Repair Energy fuels cell division and tissue regeneration. 2 Movement Muscle contraction and locomotion require energy. 3 Maintaining Body Functions Keeping vital organs working optimally. 4 Reproduction The process of creating new life forms.

3. Aerobic Respiration: Energy with Oxygen Aerobic respiration is the most common form of respiration, occurring in the presence of oxygen. It's highly efficient, breaking down glucose completely into carbon dioxide and water, releasing a significant amount of energy. Process: Glucose + Oxygen → Carbon Dioxide + Water + Energy Location: Primarily in the mitochondria of cells. Energy Yield: High amount of usable energy (ATP). Organisms: Most animals, plants, and microorganisms.

4. Anaerobic Respiration: Energy Without Oxygen When oxygen is limited or absent, organisms resort to anaerobic respiration. This process is less efficient and produces less energy, often leading to by-products like lactic acid or alcohol. Lactic Acid Fermentation Occurs in muscle cells during strenuous exercise when oxygen supply is insufficient. Leads to muscle cramps. Equation: Glucose → Lactic Acid + Low Energy Alcoholic Fermentation Common in yeast and some bacteria. Used in brewing and bread-making. Equation: Glucose → Alcohol + Carbon Dioxide + Low Energy

5. Breathing in Humans: Inhalation & Exhalation Breathing is the physical process of taking in oxygen and expelling carbon dioxide. It involves two main phases: Inhalation (Breathing In) The diaphragm contracts and moves downwards, while the rib cage moves upwards and outwards. This increases the volume of the chest cavity, drawing air into the lungs. Exhalation (Breathing Out) The diaphragm relaxes and moves upwards, and the rib cage moves downwards and inwards. This reduces the volume of the chest cavity, forcing air out of the lungs.

6. The Human Respiratory System: Organs & Their Roles Our respiratory system is a complex network designed for efficient gas exchange. Nostrils Entry point for air, filters dust and warms air. Nasal Cavity Warmer and humidifies incoming air. Pharynx & Larynx Passageway for air; larynx contains vocal cords. Trachea (Windpipe) Carries air from larynx to bronchi, supported by cartilage rings. Bronchi Two tubes branching from trachea into lungs. Lungs Primary organs of respiration, containing bronchioles and alveoli. Alveoli Tiny air sacs where oxygen and carbon dioxide exchange occurs.

7. Respiration in Other Animals: Varied Mechanisms Different animals have adapted unique ways to respire based on their habitat and complexity. Earthworms Breathe through their moist skin. They absorb oxygen directly from the environment and release carbon dioxide. Fish Use gills to respire. Water passes over the gills, and oxygen is absorbed into the blood while carbon dioxide is released. Insects Have a network of air tubes called tracheae that open to the outside through spiracles for direct gas exchange. Frogs Respire through their skin (when moist), lungs, and buccal cavity, adapting to both aquatic and terrestrial environments.

8. Respiration in Plants: Stomata and Lenticels Plants also respire, exchanging gases with the atmosphere. They use different structures for this process: Stomata Tiny pores primarily on the surface of leaves. They open and close to regulate the exchange of gases (carbon dioxide, oxygen, and water vapour) with the atmosphere. Lenticels Small, raised pores found on the bark of woody stems and roots. They facilitate gas exchange between the internal tissues of the plant and the outside air.

9. Difference Between Breathing and Respiration While often used interchangeably, breathing and respiration are distinct processes. Breathing Respiration A physical process involving inhalation and exhalation of air. A biochemical process of breaking down food to release energy. Involves lungs, diaphragm, and rib cage (in humans). Occurs at the cellular level, in cytoplasm and mitochondria. No energy is released, it requires energy. Energy (ATP) is released. Mechanical process. Chemical process. No enzymes are involved. Requires various enzymes.

10. Key Takeaways & Importance of Respiration Respiration is fundamental for all life, enabling organisms to thrive by providing the necessary energy for all biological processes. 1 Energy Production The primary function, converting food into usable energy (ATP). 2 Waste Removal Eliminates carbon dioxide, a by-product of metabolic activity. 3 Life Sustenance Supports all vital functions from growth to reproduction. 4 Adaptation Varied mechanisms across organisms highlight evolutionary adaptations.