U3 AOS2 Topic 7: Factors Affecting Cellular Respiration Rate

Factors affecting the rate of cellular respiration involve

·        Temperature and pH

·        availability of glucose

·        concentration of oxygen

·        enzyme inhibitors

Temperature and pH:

As the biochemical pathways in cellular respiration are catalyzed by some essential enzymes, optimum temperature and pH is very important for the maximum rate of cellular respiration. When temperature is below optimum temperature, the enzymes and substrates have less kinetic energy to carry out the reaction and when temperature is above optimum temperature, the enzymes become denature. Similarly, when pH of an enzyme above and below of its optimum pH then enzyme become denature and reaction cannot proceed.

Availability of glucose:

Glucose is the input of glycolysis in both aerobic and anaerobic respiration. Increasing glucose concentration can increase the rate of cellular respiration and ATP production until a saturation point where the reaction rate is maximum and all enzymes are saturated with substrate and no more enzymes are available for the reaction.

Concentration of oxygen:

Increasing the concentration of oxygen increases the rate of cellular respiration until a saturation point is reached. In animals when there is less concentration of oxygen, the aerobic respiration shifts to anaerobic respiration where oxygen is not needed.

Enzyme inhibitors:

Competitive and non-competitive enzyme inhibitors can decrease the rate of cellular respiration. As competitive inhibitors bind to active site and block the substrate from binding whereas non competitive inhibitors bind to allosteric site to change the shape of enzyme and hence prevent the substrate from binding.