11 Bio Chapter Summary

Plant Respiration

Chapter Summary

  • The complete combustion of glucose yields energy during respiration. Most of the energy produced during respiration is given out as heat. CO2 and H2O are the end products of respiration.
  • Respiration happens in two main steps in all living beings, viz. glycolysis and processing of pyruvate.
  • Glycolysis involves breaking down glucose into pyruvate. This is common in all living beings.



  • In anaerobic respiration, pyruvate is further processed to produce either lactic acid or ethyl alcohol. There is incomplete oxidation of glucose in anaerobic respiration.
  • In aerobic respiration, pyruvate is further processed to produce carbon dioxide and water; alongwith energy. There is complete oxidation of glucose in case of aerobic respiration.
  • The respiratory balance sheet gives theoretical value about net gain of ATP for every glucose molecule oxidized.
  • Respiratory process involves both catabolism and anabolism; because breakdown and synthesis of substrates are involved. Hence, respiratory pathway is considered as an amphibolic pathway rather than a catabolic one.
  • The ratio of the volume of CO2 evolved to the volume of O2 consumed during respiration is called the respiratory quotient (RQ) or respiratory ratio. The RQ for carbohydrates is 1. The RQ for fat and protein is less than 1.