October 5, 2012.
In the process of aerobic respiration which is a process of cellular respiration that uses oxygen in order to break down the molecules. The formula for this is Co2 + H2O. Which are then releases the electrons and creates energy. Food materials are oxidized and energy (glucose) is stored in the form of high-energy phosphate bonds. Carbon dioxide (Co2) and water (H2O) vapor are released as a by-product.
In contrast to photosynthesis, respiration occurs in all living cells. By using simple tests, we can gain indirect evidence as to the occurrence and nature of respiration.
In this lab, we will try to demonstrate the net change in the carbon dioxide (Co2) and water (H2O) vapors when the radish sprouts are placed in Bromothymol Blue (BTB), as a means of demonstrating the presence or absence of Co2. The formula for this is Co2 + H2O=Acid.
This solution changes color when Co2 and H2O are introduced. Bromothymol Blue changes color due to the change in the PH. When Co2 is diluted in the water, it forms a carbonic acid. This lowers the PH of the solution and causes the BTB to change its appearance. The formula for this is BTB + Acid= Blue to “Straw” coloring.
If we use the BTB which is a commonly used acid base indicator that turns straw colored as the PH becomes acidic, and add radish sprouts to the BTB in test tube # 1 will it then undergo respiration and turn the BTB to “straw” color for a positive test result? Will the BTB in test tube # 2 turn “straw” color or will it stay the blue color?
Method: Step 1: Obtain 2 clean test tubes. Step 2: Number the test tubes #1 and #2. Step 3: Add 1 inch of Brommthymol Blue to each test tube. Step 4: Place 8 radish sprouts to test tube #1. Step 5: Put a stopper on each of the test tubes to control the environment. Step 6: Chart the time. Step 7: Look at the test tubes every 1-2 minutes and record the results. Step 8: Allow each test tube to sit for 30 minutes. Step 9: After 30 minutes check your results. Step 10: Record and chart all your results.
When the test was done and recorded it indicate that test tube #1 had a positive result, which turned the BTB from the blue color to the “straw” color. The color in test tube #2 was still the same color of blue indicating no changes occurred during the test.
Discussion: When putting radish sprouts into the test tube #1 with the BTB we predicted that