Obtaining the Materials for Respiration

Obtaining the Materials for Respiration

Introduction to Respiration

  • Respiration is a vital biochemical process in all living organisms.
  • It involves the breakdown of glucose (a sugar molecule) to release energy.
  • The energy released is used for various cellular activities.

Glucose Source and Transport

  • Glucose is a key reactant in respiration. Most organisms get glucose from the food they eat.
  • After digestion, glucose is absorbed into the bloodstream in animals or transported to cells in plants.
  • In plant cells, glucose is manufactured through photosynthesis, a process that uses light to combine water and carbon dioxide.

Oxygen Source and Transport

  • Oxygen, another reactant in respiration, is obtained from the air in animals and from the atmosphere in green plants.
  • In animals, oxygen enters through the respiratory system and is carried to cells via the bloodstream.
  • In plants, oxygen is absorbed from the environment directly through microscopic pores, known as stomata.

Transport of Carbon Dioxide

  • Carbon dioxide, a by-product of respiration, is excreted by cells and transported away.
  • In animals, carbon dioxide diffuses into the bloodstream, travels to the lungs, and is expelled during exhalation.
  • In plants, carbon dioxide is diffused through stomata and used in photosynthesis or released into the atmosphere during the day.

Role of Mitochondria

  • The final stages of respiration occur in cell structures called mitochondria.
  • Here, oxygen is used to break down glucose fully, in a process known as aerobic respiration, releasing energy, water and carbon dioxide.

Stored Energy: ATP

  • The energy produced during respiration is most immediately stored in a molecule called ATP (Adenosine TriPhosphate).
  • ATP can be easily used by cells, making it the primary energy delivery molecule in most organisms.

Anaerobic Respiration

  • In the absence of sufficient oxygen, some organisms perform anaerobic respiration.
  • This process yields less energy and produces different by-products, such as lactic acid in animals and ethanol in yeast.