Post-Lab Analysis Cellular Respiration

1. What gas is being consumed by the germinating pea?  oxygen

2. Write a balanced equation for the process of cellular respiration.  C 6 H O 2 ---> 6CO 2 + 6H ATP

3. What is the germinating seed using for energy?  Glucose

4. What specific activities are going on in the peas as they germinate?  Respiration, growth, & development

5. Why is it necessary to correct the readings for the peas with those of the glass beads? Explain.  So that only oxygen used by the peas is measured = accurate data  Changes that are due to temperature or pressure differences rather than actual oxygen consumption by peas must be subtracted from the readings  So that only oxygen used by the peas is measured = accurate data  Changes that are due to temperature or pressure differences rather than actual oxygen consumption by peas must be subtracted from the readings

6.A = True B = False In a closed system, such as these vials, the number of molecules of gas taken in is equal to the number of molecules of carbon dioxide gas given off during cellular respiration.  A - True. The balanced equation shows 6 molecules of oxygen reacting and 6 molecules of carbon dioxide being produced.

7. What effect does the KOH have on the total number of gas molecules in the vial? Explain.  Reduces it - KOH converts the CO 2 gas into a solid, therefore lowering the number of gas molecules in the vial

8. How does this affect the air pressure in the vial? How does this affect the amount of movement in the bubble (total oxygen consumption) over time?  Less gas = less pressure; as pressure drops, water moves inward, toward the vial

9. Calculate the amount of oxygen consumed per minute for each vial.  Final Reading/12 (total # of minutes) = _____ mL of oxygen/minute  Final Reading/12 (total # of minutes) = _____ mL of oxygen/minute

10. Explain why the germinating seeds use more oxygen per minute than the dry seeds.  Both consume oxygen but the germinating peas need more energy for growth and development. Therefore, they respire at a higher rate.

11. What is the effect of temperature on the volume of a gas? How will this affect the readings of oxygen consumption?  Directly proportional - an increased temperature = increased gas volume & vice versa.  The oxygen readings are greater at higher temperatures  Directly proportional - an increased temperature = increased gas volume & vice versa.  The oxygen readings are greater at higher temperatures

12. How does temperature affect the rate of metabolic reactions within a living organism? Explain.  The respiration rate of warm-blooded animals is independent of environmental temperature but for plants and cold-blooded animals, a drop in temperature results in a decreased respiration rate.