Cell respiration is the controlled release of energy from organic compounds in cells to form ATP,and then release waste products. The process of cell respiration can take place in the presence or absence of oxygen. In either case,the first stage of cell respiration is glycolysis.The effect of temperature on cell respiration mainly depends on the effect of temperature on of enzyme activity.Generally speaking in a certain temperature range,as the temperature rises, the rate of cellular respiration will enhance, molecules have more motion and activity.On the other hand,as the temperature decreases, the rate of cellular respiration will weaken and molecules have less motion and activity.However, if the temperature is slightly higher than the optimum temperature, the activity of enzyme will start to decreases and the cell respiration will stop.As shown below.
From the figure above, we can observe point B is optimum temperature.On this occasion,cell respiration rate will be the highest.
How will the different temperature affect cell respiration? In this experiment,we will have to measure the change of carbon dioxide released in the process of cell respiration under different temperatures (7℃,25℃,60℃). As carbon dioxide is the byproduct in the process of cell respiration,the more active the cell respiration is, the more carbon dioxide will be released. Hypothesis:
The hypothesis is that when the temperature at 25℃, has the maximal reactivity of cell respiration rate. If we lower the temperature at 7℃ or raise it above 60 ℃ , the rate of cell respiration would slow down,because at the very low temperature(7℃) enzyme will be inactive and at a very high temperature (above 60 ℃ ), the enzyme would denature and the structure of it changes permanently.
• Thermometer (range 0 ℃ to 100 ℃ )