C E L L R E S P I R A T I O N L A B By: Kelly Blochlinger, Andrew Lazo, Cecelia Sha

P R O B L E M How does temperature affect the rate of cellular respiration in peas?

H Y P O T H E S I S The Seeds will have the highest rate (steepest slope) of respiration at 30 degrees Celsius, the second highest at room temp (18 degrees), and the lowest rate at 8 degrees Celsius. B A C K G R O U N D Cellular respiration harvests the energy in carbon compounds to produce ATP. For every molecule of O2 consumed, one molecule of CO2 is produced. To measure the rate of respiration, KOH was added to the bottom of the test tube to remove the CO2 and cause a pressure change. Respiration involves enzymes. Enzymes work faster as temperature increases, but they denature if the temperature is too high. The enzymes involved in respiration in peas are most efficient between 10 and 30 degrees Celsius.

P R O C E D U R E 1.Set up the respirometers with general procedure. 2.Place 2 test tubes with stopper (1 with peas, 1 with glass beads (control)) in beaker of water of desired temp (room temp (18 ̊ C), heated (29 ̊ C), cooled (8 ̊ C)) for 10 minutes to allow the inside of the test tube to equal the temperature of the water. Do each temperature separately. 3.Place the boxes with the gas pressure sensors at the same height as the test tubes to prevent the pressure on the tube from effecting results. 4.Attach gas pressure sensors onto test tubes and allow data to collect for 20 min. while maintaining the temperature in the beaker.

R E S U L T S Trial Number and Temp (in Celsius) Rate of respiration in kPa/min T1- 18 (pressure sensor 1) T4-29 (pressure sensor 1) T4-29 (pressure sensor 2) T5-8 (pressure sensor 1) T5-8 (pressure sensor 2) Most Efficient to least Efficient: Room Temp. 8 degrees Celsius 29 degrees Celsius Trial Number and Temp (in Celsius) Rate of respiration in kPa/min T1- 18 (pressure sensor 2) T4-29 (pressure sensor 3) T5-8 (pressure sensor 3) ControlsCorrected Data (includes controls)

6 Raw Data Trial at 8˚C Trial at 18˚C Trial at 29˚C

C O N C L U S I O N Fastest rate of respiration is at 18˚C, the second fastest is at 8˚C, and the slowest is at 29˚C. 18˚C is a higher rate than 29˚C because the enzymes may have started to denature at 29˚C. The average rate at 29˚C is 49% of the rate at 18˚C and 53% of the rate at 8˚C, which is a significant difference. The rate of respiration is higher at 18˚C than 8˚C because the enzymes are working faster at the higher temperature and they are not denaturing. The results do not agree with our hypothesis. We assumed that the enzyme would not denature around 30˚C, but the results proved that the enzyme began to.

8 C O N C L U S I O N (cont.) In performing our experiment we had difficulty with the gas pressure sensor tubes. We had to repeat the trials and correct the tubes by placing them at the same height as the test tubes. We were able to perform the mathematical routines with our data that were used to analyze it. We factored the controls into the results with by subtracting the controls. Questions the lab led us to: What is the most efficient temperature for the enzyme involved? At what temperature does the enzyme completely denature? What low temperature stops respiration?