Respiration

Key Notes:–

Definition of Respiration:

  • Respiration is a biochemical process in which cells obtain energy by breaking down glucose and other molecules in the presence of oxygen. This process is essential for sustaining life.

Types of Respiration:

  • Aerobic Respiration:
    • Occurs in the presence of oxygen.
    • Glucose is completely broken down into carbon dioxide and water.
    • Produces a large amount of energy (approximately 36-38 ATP molecules per glucose molecule).
  • Anaerobic Respiration:
    • Occurs in the absence of oxygen.
    • Glucose is partially broken down into lactic acid (in animals) or ethanol and carbon dioxide (in plants and yeast).
    • Produces less energy (approximately 2 ATP molecules per glucose molecule).

Equation of Respiration:

  • Aerobic Respiration:
    • C6​H12​O6​ + 6O2 ​→ 6CO2​ + 6H2​O + Energy (ATP)
  • Anaerobic Respiration (in muscles):
    • C6​H12​O6​ → 2C3​H6​O3 ​+ Energy (ATP)
  • Anaerobic Respiration (in yeast):
    • C6​H12​O6​ → 2C2​H5​OH + 2CO2 ​+ Energy (ATP)

Respiratory System:

  • Human Respiratory System Components:
    • Nose and Nasal Cavity: Warms, moistens, and filters air.
    • Pharynx: Passageway for air and food.
    • Larynx (Voice Box): Contains vocal cords.
    • Trachea (Windpipe): Connects larynx to bronchi; lined with cilia to trap particles.
    • Bronchi and Bronchioles: Airways that lead from the trachea to the lungs.
    • Lungs: Main organs of respiration where gas exchange occurs.
    • Alveoli: Tiny air sacs in the lungs where oxygen and carbon dioxide are exchanged.

Gas Exchange:

  • Occurs in the alveoli of the lungs.
  • Oxygen from inhaled air diffuses into the blood, and carbon dioxide from the blood diffuses into the alveoli to be exhaled.

Role of Hemoglobin:

  • Hemoglobin in red blood cells binds to oxygen in the lungs and transports it to the tissues where it is released.

Energy Release and ATP:

  • The energy released during respiration is stored in the form of ATP (Adenosine Triphosphate), which is used by cells for various activities.

Importance of Respiration:

  • Provides energy for cellular activities.
  • Helps in maintaining body temperature.
  • Removes carbon dioxide, a waste product of metabolism, from the body.

Respiration vs. Photosynthesis:

  • Photosynthesis occurs in plants, using carbon dioxide and water to produce glucose and oxygen.
  • Respiration occurs in both plants and animals, using glucose and oxygen to produce energy, carbon dioxide, and water.

Disorders Related to Respiration:

  • Asthma: A condition where the airways become narrow and inflamed, making breathing difficult.
  • Bronchitis: Inflammation of the bronchial tubes, leading to coughing and difficulty in breathing.
  • Emphysema: A lung condition where the alveoli are damaged, reducing the surface area for gas exchange.

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