Question

Context: I did a lab about photosynthesis where I placed a plant inside a beaker that’s filled with water. After some time, bubbles (oxygen) started forming out of the leaves of the plant.

Question:
1. Why was the amount of oxygen a good indicator of photosynthesis occurring?
2. Could the dependent variable have been the production of glucose (another product of photosynthesis) instead of oxygen? How would this have been tested?

Answer 1

1. The amount of oxygen is a good indicator of photosynthesis occurring because oxygen is produced as a byproduct of photosynthesis. During photosynthesis, plants use carbon dioxide and water to produce glucose (a type of sugar) and oxygen gas. The oxygen gas is released into the atmosphere as a waste product, which is why we see bubbles coming out of the leaves of the plant during photosynthesis.

2. Yes, the dependent variable could have been the production of glucose instead of oxygen. To test for the production of glucose, we would need to use a chemical test, such as the Benedict's test, which detects the presence of reducing sugars like glucose. We could extract the plant material and test for the presence of glucose in the sample, comparing it to a control sample that did not undergo photosynthesis. Alternatively, we could use a colorimetric assay that detects the amount of glucose present in the sample by measuring the absorbance of a specific wavelength of light.

Answer 2

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1. The amount of oxygen is a good indicator of photosynthesis occurring because oxygen is a byproduct of the process. During photosynthesis, plants use carbon dioxide and water to produce glucose and oxygen. Therefore, the presence of oxygen indicates that the plant is producing glucose through photosynthesis.

2. Yes, the dependent variable could have been the production of glucose instead of oxygen. This could have been tested by measuring the amount of glucose produced by the plant over time. One way to do this is to extract the glucose from the plant using a solvent and then measure the amount of glucose using a colorimetric assay. Alternatively, the amount of glucose produced could be estimated indirectly by measuring the amount of carbon dioxide consumed by the plant, since carbon dioxide is used in photosynthesis to produce glucose.