respiration and exercise

• respration is an exothermic reaction- it releases energy from glucose molecules for use by the body
• organisms need energy from respiration:

  • for chemical reactions to build larger molecules
  • for movement
  • to keep warm
• what are the 2 types of respiration?

  1. aerobic (with oxygen)
  2. anaerobic (without oxygen)
• what is the word equation for aerobic respiration?

  Glucose + Oxygen -> Carbon Dioxide + Water + Energy
• what is the word equation for anaerobic respiration in animals?

  glucose -> lactic acid + energy
• what is the word equation for anaerobic respiration in plants?

  glucose -> ethanol + carbon dioxide + energy
• in anaerobic respiration, the glucose isn't fully broken down meaning it transfers much less energy than aerobic
• anaerobic respiration in yeast cells is called fermentation
• what is fermentation used to manufacture:

  • bread
  • alcoholic drinks
• during exercise, the body demands more energy so the rate of respiration increases
• during exercise, the heart rate, breathing rate and breath volume all increase to supply the muscles with more oxygen and glucose for the increase in aerobic respiration
• during periods of vigorous activity, muscles may not get supplied with enough oxygen so anaerobic respiration starts to take place in muscle cells which causes a build up of lactic acid and created an oxygen debt
• lactic acid causes the muscles to ache and stops them contracting effectively. lactic acid is a poison so needs to be removed quickly
• after exercise, blood flowing through the muscles transports the lactic acid to the liver where it is converted back to glucose
• the oxygen debt is the amount of extra oxygen the body needs after exercise to react with the lactic acid and remove it from the cells
• metabolism is the sum of all the chemical reactions in a cell/ in the body

  • controlled by enzymes
  • many need a transfer of energy (transferred by respiration and used to make new molecules)