Gas balance in respiration and photosynthesis

What plants make by photosynthesis, plants and animals break down by respiration. In any community, the balance of carbon dioxide and oxygen is essential to all elements of the community. In individual organisms, detailed analysis of gas exchange can give an insight into the chemical processes within the organisms.

Experiments

• Measuring respiratory quotient
  Use a respirometer to measure the volumes of carbon dioxide given out and oxygen absorbed as living material respires. Calculate the ratio as evidence of substrate used.
• Measuring the rate of metabolism
  Use a respirometer to follow uptake of oxygen by respiring plant or invertebrate material.
• How do plants and animals change the environment around them?
  Demonstrate that, through photosynthesis, plants reduce the amount of carbon dioxide in their environment; while through respiration, both animals and plants increase it.