Respiration

• Respiration


  A chemical process whereby nutrient molecules like glucose are broken down by enzymes to release usable energy or ATP
• Energy-consuming processes in the body

  • Contraction of muscle cells to produce whole body movements
  • Pump blood around the body
  • Peristalsis in the alimentary canal
  • Synthesis of proteins from amino acids
  • Transmission of impulses
  • Cell division (mitosis)
  • Active transport of molecules across cell membranes against a concentration gradient
• Energy


  • Enables organisms to grow through the formation of new cells or a permanent increase in cell size
  • Allows warm-blooded animals to maintain a constant body temperature so that enzyme-controlled reactions continue at a predictable rate
• Investigating the effect of temperature on respiration in yeast

  1. Add glucose solution and a suspension of dried yeast to a sidearm boiling tube

  2. Place in a water bath at a fixed temperature

  3. Leave for a few minutes to allow the contents to adjust to the temperature

  4. Attach a gas syringe to the sidearm

  5. Leave for a set period of time allowing gas to collect in the syringe

  6. Record the volume of gas produced

  7. Repeat the process at a range of different temperatures

  8. Calculate rate of gas production at each temperature

  9. Plot results on a graph
• As temperature rises


  Enzyme activity increases resulting in a faster rate of respiration and carbon dioxide production
• Reaching an optimum temperature


  Enzymes begin to denature and rate of respiration slows