Respiration 🌬️

Respiration is the process of releasing energy from food substances within cells. It’s mainly classified as:

• Internal (Cellular) Respiration 🏢: Takes place inside cells in organelles called mitochondria.
• External Respiration 🌍: Refers to the process of breathing and gaseous exchange that supplies oxygen to cells and removes carbon dioxide.

Types of Internal Respiration 🔍

Aerobic Respiration 🌱

• Requires oxygen. 💨
• Produces high energy (around 2880 KJ from one mole of glucose). ⚡
• By-products are carbon dioxide and water. 💧

Equation:

Word: Glucose + Oxygen → Carbon dioxide + Water + Energy 💡

Chemical: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (2880 KJ)

Anaerobic Respiration 🚫🌬️

• Occurs without oxygen. ❌💨
• Produces less energy and two types of fermentation processes:

Alcoholic Fermentation 🍷

• Produces alcohol, carbon dioxide, and energy, commonly occurs in yeast. 🍞
• Equation:
• Word: Glucose → Alcohol + Carbon dioxide + Energy 💡
• Chemical: C₆H₁₂O₆ → 2CO₂ + 2C₂H₅OH + Energy (210 KJ)
• Uses: Brewing 🍺 and baking rely on yeast to produce carbon dioxide and alcohol.

Lactic Fermentation 🏋️‍♂️

• Produces lactic acid and a small amount of energy, occurs in muscle cells during intense exercise. 💪
• Equation:
• Word: Glucose → Lactic acid + Energy 💡
• Chemical: C₆H₁₂O₆ → 2C₃H₆O₃ + Energy (150 KJ)

ATP and Its Role in Energy Transfer ⚡

ATP (adenosine triphosphate) serves as an energy carrier. Cells convert energy from respiration into ATP, which can then be broken down to release energy as needed. ATP enables energy storage and transfer within cells, making energy available where and when it's needed. 🔋

Experiments Demonstrating Respiration 🔬

1. Respiration in Germinating Seeds 🌱

• Method: Soak and germinate one set of seeds, while another set is boiled. Place each set in separate thermal flasks, measure temperature changes over four days. 📅
• Observation: Temperature rises in the flask with germinating seeds, indicating respiration. 🌡️

2. Respiration in Soil Organisms 🐛

• Method: Set up two samples of soil (one heated, one unheated), observe movement of oil drops in capillary tubes. 🧪
• Observation: Oil drop moves in unheated soil sample, showing that organisms in soil respire. 🌍

3. Respiration in Plants 🌿

• Method: Place a plant in a sealed bottle with a capillary tube in a dark place, observe movement of oil drop. 🌑
• Observation: Oil drop moves inward, indicating oxygen is used during respiration. 💨

4. Carbon Dioxide Production in Respiration 💨

• Method: Set up an experiment with a small animal and lime water to observe carbon dioxide output. 🐭
• Observation: Lime water in the animal’s exhaled air turns milky, indicating higher CO₂ levels. 🥛

Breathing and Gaseous Exchange 🌬️

Breathing 🫁

• Humans: Air moves in and out of lungs; process involves diaphragm and intercostal muscles. 🧍‍♂️
• Fish: Water flows over gills, allowing oxygen intake and carbon dioxide release. 🐟
• Insects: Use spiracles and tracheal tubes for direct gas diffusion. 🐜

Mechanics of Breathing in Humans 🫁

Breathing Parameters 📊

• Breathing Rate: Number of breaths per minute (average adult rate at rest: ~18). 🕒
• Tidal Volume: Air per breath at rest (500 cm³). 🌊
• Vital Capacity: Max exhaled after full inhalation (3500 cm³). 💨
• Residual Volume: Air remaining post-expiration (1500 cm³). 🌀

Composition of Inspired and Expired Air 🌬️

Gaseous Exchange in Humans 🩸

Occurs in alveoli where oxygen diffuses into blood, and CO₂ diffuses out. 🩸

Characteristics of Gaseous Exchange Surfaces 🌊

• Large surface area.
• Moist to facilitate gas diffusion.
• Thin for minimal diffusion distance.
• Close association with transport system.
• Good ventilation to maintain diffusion gradient.

Effects of Smoking on Respiratory Health 🚬

Cigarette smoke contains harmful substances like nicotine, tar, and carbon monoxide, which contribute to:

• Bronchitis: Inflammation of air passages, caused by mucus buildup.
• Emphysema: Alveoli burst, reducing surface area for gas exchange.
• Lung Cancer: Uncontrolled cell division, increased risk from tar (a carcinogen).

Gaseous Exchange in Other Organisms 🐠

• Fish: Use gills for oxygen intake and CO₂ release. Water flows over gills where gases are exchanged.
• Insects: Tracheal system with spiracles and tracheoles allows direct gas exchange without blood transport.

Plant Respiration and Gaseous Exchange 🌱

• Daytime (Photosynthesis): Takes in CO₂, releases O₂.
• Nighttime (Respiration): Takes in O₂, releases CO₂.

Gaseous exchange in plants primarily occurs in the spongy layer of leaves. 🍃