Biology Respiration Rate Calculator
Calculate O₂ consumption rate from respirometer data
Leave blank for absolute rate only
Please enter valid numerical values for volume and time.
Volume Change (O₂ Consumed): 0 mL
Absolute Respiration Rate: 0 mL/min
Mass-Specific Respiration Rate: 0 mL/min/g
How to Calculate Rate of Respiration in Biology
Calculating the rate of respiration is a fundamental skill in biology, particularly in physiology and ecology. It measures how fast an organism consumes oxygen or produces carbon dioxide. In laboratory settings, this is often performed using a respirometer, a device that measures changes in gas volume.
The Formula
The general formula for calculating the rate of respiration based on oxygen consumption is:
Rate = ΔV / t
Where:
- ΔV (Delta V): The change in volume of oxygen (Initial Reading – Final Reading).
- t: The time interval over which the change occurred.
Mass-Specific Respiration Rate
To compare the respiration rates of different organisms (e.g., a mouse vs. a cricket), scientists normalize the data by the mass of the organism. This is known as the mass-specific metabolic rate.
Specific Rate = (ΔV / t) / Mass
Step-by-Step Calculation Guide
- Record Initial Reading: Note the starting position of the fluid in the respirometer pipette (e.g., 5.0 mL).
- Wait for Time Interval: Allow the organism to respire for a set time (e.g., 10 minutes). Ensure CO₂ is being absorbed by a substance like Potassium Hydroxide (KOH) so the volume change reflects only Oxygen consumption.
- Record Final Reading: Note the new position of the fluid (e.g., 4.2 mL).
- Calculate Change: Subtract final from initial to find volume consumed (5.0 – 4.2 = 0.8 mL).
- Divide by Time: 0.8 mL / 10 min = 0.08 mL/min.
- Divide by Mass (Optional): If the organism weighs 5g, then 0.08 / 5 = 0.016 mL/min/g.
Why Measure Respiration?
Respiration rates indicate the metabolic activity of an organism. Factors affecting this rate include temperature (metabolism typically increases with heat), the organism's activity level, age, and species. In germinating seeds, for example, the rate of respiration increases significantly as the seed breaks dormancy and begins to grow.