bio 1003 lab notes baruch
Experimental setup 1 contains live, germinating pea seeds.
Experimental setup 2 contains germinated then boiled pea seeds.
Experimental setup 3 contains dry pea seeds that have not begun to germinate.
Experimental setup 4 is a tube of phenol red and glass pipette.
Gasses have accumulated in the space above the seeds. You will see a sealed thistle tube that penetrates the lid and another tube that leads from the experimental container into the phenol red solution in a test tube. The accumulated gas can be pushed out and bubbled through the phenol red by unstopping the thistle tube and filling the space up with water.
Acid can be detected with phenol red solution. Phenol red solution has the property that it is yellow if the pH is acidic (<7) and pink if basic (>7).
What do you predict the color of phenol red will be in each of the setups.
Experiment 1
Experiment 2
Experiment 3
To predict the color of phenol red in each of the setups, we need to understand the reactions that might occur in each experiment and their impact on the pH level.
Experiment 1: Live, germinating pea seeds
When pea seeds germinate, they release carbon dioxide (CO2) as a byproduct of cellular respiration. The accumulation of carbon dioxide can make the surrounding environment acidic. Phenol red is yellow in an acidic environment, so we can predict that the color of phenol red in this setup will be yellow.
Experiment 2: Germinated then boiled pea seeds
Boiling the germinated pea seeds will likely kill the living cells, including those involved in cellular respiration. Therefore, there will be no production of carbon dioxide in this setup, and the pH of the environment will not become acidic. As a result, the phenol red will remain its original color, which is likely pink.
Experiment 3: Dry pea seeds that have not begun to germinate
Dry pea seeds that have not germinated are inactive and not releasing carbon dioxide through cellular respiration. Hence, there will be no significant accumulation of carbon dioxide, and the pH of the environment will remain unchanged. In this setup, the color of phenol red is likely to remain as it was initially, which could be pink or another color, depending on the starting pH.
It's important to note that these predictions are based on general scientific knowledge and assumptions. Conducting the experiment and observing the actual colors of the phenol red in each setup will provide the most accurate results.