Pre - Lab Cellular Respiration

1. What effect do changes in temperature have on the volume of a gas? The volume of the gas changes in direct proportion to the temperature. An increase in temperature = An increase in volume & vice versa.

2. Which of the 3 vials will serve as a control? Why is that necessary? Vial with beads only This vial enables us to correct for changes in gas volume that are due to changes in temperature or barometric pressure rather than consumption of oxygen.

3. Do you expect germinating seeds to consume a different amount of oxygen when compared to the dry seeds? Explain. Yes. Respiration rates are slower in dry, dormant seeds. The rate of respiration increases during germination because the seeds need more energy for growth & development.

4. What is the purpose of the KOH in this experiment? To remove the carbon dioxide produced by the peas during germination by converting it to a solid precipitate. This means that changes in the volume of gas in the respirometer will be directly related to the amount of oxygen consumed.

5. What is the independent variable in this experiment? The type of pea used – germinating vs. non-germinating.

6. What is the dependent variable in this experiment? The volume of oxygen gas consumed by the peas.

7. What are we trying to show when comparing respirometers on the right side of the room compared to the left side of the room? That change in temperature is directly proportional to the volume of gas.

8. What gas is being consumed by the peas? Oxygen

9. In which direction does the water level move in the tube during this experimant? Explain. Toward the peas. As the volume of gas goes down (oxygen is consumed and the carbon dioxide produced is turned into a solid) the pressure also drops

10. Why should you keep your hands out of the water during the course of the experment? To prevent outside influences on data. Hands in the water may cause temperature change/ bumping the respirometer may allow water to re-enter the pipette.