CellRespLab-Handout BIO 101

Activity 2 Data Table 2 Water temp. (°C) Time (min) Resp. #1 Volume in pipet Resp. #1 Change in volume Resp. #1 Correcte d volume change Resp. #2 Volume in pipet Resp. #2 Change in volume Resp. #2 Correcte d volume change Resp. #3 Volum e in pipet Resp. #3 Change in volume 26 0 0.22 - - 0.01 - 0.00 - 25 5 0.60 0.38 0.38 0.05 0.04 0.04 0.00 0.00 25 10 1.05 0.45 0.40 0.10 0.05 0.00 0.05 0.05 25 15 1.15 .10 0.09 0.18 0.08 0.07 0.06 0.01 25 20 1.70 0.55 0.52 0.24 0.06 0.03 0.09 0.03 1. Which of the respirometers serves as control? Explain your answer. In this experiment, respirometers are used to measure the rate of respiration in different conditions. The negative control is the respirometer which only contains beads. This is because the beads do not respire, and therefore, any change in the oxygen levels in this respirometer can be attributed to factors other than respiration, such as changes in atmospheric pressure or temperature. This helps to ensure that the changes observed in the other respirometers are indeed due to respiration. The positive control is the respirometer containing peas. The germination of peas involves respiration, which consumes oxygen and produces carbon dioxide. The KOH (potassium hydroxide) in the respirometer absorbs the carbon dioxide produced, creating a change in pressure that draws the food coloring down the pipet. This allows the rate of respiration to be visually observed and measured.

metabolically active and therefore have a lower rate of respiration. The KOH (potassium hydroxide) in the vials served to absorb the carbon dioxide produced during respiration, ensuring that any changes in the gas volume in the respirometer were due to oxygen consumption only. As time increased, the rate of oxygen consumption also increased, likely because the germinating peas continued to grow and require more energy, leading to increased cellular respiration. This is why the food coloring moved down the pipet even farther and faster over time.