Question

During metabolism, bonds between molecules are continuously created and destroyed. The generation of ATP during respiration requires the breakdown of sugar molecules, but not all the energy released from the breaking of the bonds is captured by the cells. Some energy is lost in the form of heat. Design an apparatus and experiment that would allow you to measure the respiration rate of germinated and non-germinated peas by temperature. Use the gas law (pV = nRT) to help you.

This is from the Cellular Respiration Lab for AP Biology.

Answer 1

To design an experiment to measure the respiration rate of germinated and non-germinated peas by temperature, you can set up a simple apparatus to collect and measure the evolved gases. The idea is to measure the pressure change caused by the release of CO₂ during respiration, and you can use the ideal gas law (pV = nRT) to correlate the pressure change with the amount of gas produced.

Apparatus:

Gas syringe or displacement setup:

Connect a gas syringe or a displacement setup to a sealed container where peas are respiring.

Place a graduated scale on the gas syringe to measure the volume of gas evolved.

Sealed container:

Use a sealed container with a known volume (V) and constant temperature (T) for the peas to respire in.

Germinated and non-germinated peas:

Set up the experiment with both germinated and non-germinated peas to compare their respiration rates.

Temperature control:

Keep the experimental setup in a temperature-controlled environment. Maintain a constant temperature throughout the experiment.

Procedure:

Prepare germinated and non-germinated peas:

Germinate peas by soaking them in water until they sprout.

Keep some peas non-germinated as a control group.

Set up the apparatus:

Place the germinated and non-germinated peas in separate containers connected to the gas syringe.

Record initial conditions:

Record the initial volume (V) of gas in the syringe, initial temperature (T), and pressure (P).

Start the experiment:

Allow the peas to respire for a set period.

Measure the final volume of gas, final temperature, and pressure.

Data analysis:

Use the ideal gas law (pV = nRT) to analyze the data. The change in pressure, volume, and temperature can be used to calculate the number of moles of gas produced.

`n=\frac{\text { Change in pressure } * \text { Change in volume }}{R * \text { Change in temperature }}`

Compare the respiration rates of germinated and non-germinated peas by assessing the amount of gas produced.

Notes:

Ensure that the container is well-sealed to prevent gas exchange with the external environment.

The setup assumes constant volume during the experiment.

Use appropriate units and calibrate your equipment for accurate measurements.

By comparing the respiration rates of germinated and non-germinated peas at different temperatures, you can gain insights into how temperature influences the metabolic activity of the peas.

Answer 2

To measure the respiration rate of peas by temperature, an experimental design involving an insulated calorimeter to track temperature changes in a water bath over time can be employed. The gas law, pV = nRT, aids in quantifying these changes, with the use of gas pressure sensors to measure alterations in pressure indicative of metabolic activity.

Step-by-step explanation:

Experimental Design for Measuring Respiration Rate in Peas

To measure the respiration rate of germinated and non-germinated peas by temperature, an experiment can be designed using a calorimeter. This device measures the heat energy released from biological processes. An insulated container with water, where temperature can be monitored with a thermometer, can act as a simple calorimeter. By placing equal masses of germinated and non-germinated peas into separate containers and submerging them in a water bath inside the calorimeter, the heat released during respiration changes the temperature of the water, which can be tracked over time.

Applying the gas law (pV = nRT), where 'p' is pressure, 'V' is volume, 'n' is the number of moles, 'R' is the gas constant, and 'T' is temperature in Kelvin, can help quantify the respiration rate. As temperature increases due to respiration, pressure may also increase if volumes are kept constant. Monitoring pressure changes with gas pressure sensors also allows for calculating changes in the number of moles of gas produced during respiration.

To achieve the most accurate results, it is important to ensure constant environmental conditions, such as maintaining consistent temperature in the room where the calorimeter is stored, and to calibrate equipment carefully. Moreover, using the same species and size of peas, as well as equal starting quantities of oxygen, will provide a more reliable comparison between the metabolic rates of germinated and non-germinated peas.