respiration

• Respiration is a chemical reaction carried out in all living organisms
• Process of Respiration

  1. Energy is released from glucose either in the presence of oxygen (aerobic respiration) or the absence of oxygen (anaerobic respiration)

  2. The reactions ultimately result in the production of carbon dioxide and water as waste products

  3. Energy is transferred in the form of ATP

  
• The equation for aerobic respiration
• Respiration

  Not to be confused with gas exchange. Gas exchange involves getting oxygen into the cells and carbon dioxide out. Respiration uses the oxygen supplied from gas exchange to release energy in the form of ATP.

  
• ATP

  • Organisms need energy for chemical reactions to build larger molecules from smaller molecules, muscle contraction to allow movement, keeping warm (to maintain a constant temperature suitable for enzyme activity)
• Cellular respiration

  An exothermic reaction that is continuously occurring in living cells, releasing energy from glucose

  
• Aerobic respiration

  Requires oxygen, the complete breakdown of glucose to release a relatively large amount of energy

  
• Anaerobic respiration

  Does not require oxygen, the incomplete breakdown of glucose to release a relatively small amount of energy

  
• Differences between aerobic and anaerobic respiration

  • Need for oxygen
  • Products
  • Relative amounts of energy transferred

  
• Aerobic Respiration

  Glucose + Oxygen → Carbon Dioxide + Water

  
• Anaerobic respiration in animals

  Glucose → Lactic Acid

  
• Anaerobic respiration in plants and fungi

  Glucose → Alcohol + Carbon Dioxide

  
• Lactic acid builds up in muscle cells during anaerobic respiration, lowering the pH and potentially denaturing enzymes
• Anaerobic respiration in yeast cells is called fermentation, which is economically important in the manufacture of bread and brewing
• Practical: Demonstrating the production of carbon dioxide

  1. Measure out hydrogen carbonate indicator into boiling tubes

  2. Place germinating seeds, boiled/dead seeds, or glass beads in the tubes

  3. Seal the tubes and observe the colour change of the indicator after 3 hours
• Hydrogen carbonate indicator

  Orange in atmospheric CO2 levels, turns yellow in high CO2 levels, turns purple in low CO2 levels
• Practical: Demonstrating the production of heat

  1. Set up vacuum flasks with germinating seeds and dead/boiled seeds

  2. Record the initial and final temperatures after 4 days
• Respiration is an exothermic reaction, so the flask with germinating seeds will show an increase in temperature
• CORMS evaluation

  Considerations for practical work: Change, Organisms, Repeat, Measurement 1, Measurement 2, Same