Respirometers

What is the method for using a respirometer?

1. Organisms being investigated are placed in one tube, and non-living material of the same mass in the other tube 2. Soda lime or potassium hydroxide is placed in each tube, to absorb all CO₂ 3. Coloured fluid is poured into the reservoir of the manometer and allowed to flow in the capillary tube 4. Two rubber bungs are taken and fitted with tubes 5. As the organisms respire, they take oxygen from the air around them and give out CO₂. The removal of oxygen from the air reduces the volume and the manometer fluid moves towards the organism 6. The distance moved by the fluid can be used to measure the volume of oxygen absorbed by using V = πr²h

What is a respirometer?

A device used to measure the rate of respiration of a living organisms

How can this be done?

Calculating the Respiratory Quotient (Carbon Dioxide Produced ÷ Oxygen used up)

What RQ value do carbohydrates, proteins and fats have?

Carbohydrates - 1.0 Proteins - 0.9 Fats - 0.7

How can the volume of carbon dioxide given out be measured?

Removing the KOH and subtract oxygen used up by carbon dioxide produced without KOH

What can this be useful for?

To deduce which substrate is being used in a person's metabolism at a specific time