A series of laboratory experiments are set up to investigate various aspects of the photosynthetic process in Elodea canadensis, a common species of pond weed which lives underwater.
In the experiment a fixed quantity of Elodea canadensis is incubated underneath an inverted water-filled funnel at 20 °C in a beaker of pond water. A bright lamp is shone on the beaker. After a few hours a collection of gas is apparent in the test tube as the water it contained is displaced. The experiment is left to run for a specific time (6 hours) and the volume of gas is recorded. At the end of the experiment the gas in the test tube is tested and is found to be oxygen.
Select from the following list two items which are the most appropriate assumptions about the events taking place in the plant cells during this short amount of time.
-No ATP is manufactured during the chemical processes occurring in the plant cells.
-Only the light reactions of photosynthesis are taking place in the plant cells.
-Respiratory processes are taking place within the plant cells.
-Elodea canadensis is synthesising glucose.
-The rate of photosynthesis is much less than the rate of respiration.
Please help!!!!
- Respiratory processes are taking place within the plant cells.
-Elodea canadensis is synthesising glucose.
In order to determine the most appropriate assumptions about the events taking place in the plant cells during the experiment, let's analyze the given information and options.
In the experiment, Elodea canadensis, a species of pond weed, is incubated in an inverted water-filled funnel with a bright lamp shining on it. After a few hours, a collection of gas is apparent in the test tube, and at the end of the experiment, the gas is tested and found to be oxygen.
Based on this information, we can make the following deductions:
1. The presence of oxygen gas suggests that photosynthesis is occurring in the plant cells. Photosynthesis is the process by which plants convert light energy into chemical energy in the form of glucose, and one of the byproducts is oxygen. So, option "Only the light reactions of photosynthesis are taking place in the plant cells." is a valid assumption.
2. The bright lamp shining on the beaker is a source of light energy, which is needed for photosynthesis to occur. Therefore, it is reasonable to assume that the light energy from the lamp is being used for the photosynthetic process, rather than the plants relying solely on stored ATP (adenosine triphosphate). So, the assumption "No ATP is manufactured during the chemical processes occurring in the plant cells." is not appropriate.
3. The experiment does not provide any evidence regarding the synthesis of glucose by Elodea canadensis. Therefore, the assumption "Elodea canadensis is synthesizing glucose." cannot be determined from the given information.
4. The experiment does not provide any direct evidence of respiratory processes taking place within the plant cells. Respiration is the process by which cells convert glucose and oxygen into energy, carbon dioxide, and water. Since the experiment focuses on photosynthesis and the production of oxygen, it is more appropriate to assume that respiration is not the primary process occurring in the plant cells during the experiment. So, the assumption "Respiratory processes are taking place within the plant cells." is not justified.
5. The experiment does not provide specific information about the rates of photosynthesis and respiration, so it is not possible to determine whether the rate of photosynthesis is much less than the rate of respiration. Therefore, the assumption "The rate of photosynthesis is much less than the rate of respiration." cannot be inferred from the given information.
Based on these considerations, the two most appropriate assumptions are:
- Only the light reactions of photosynthesis are taking place in the plant cells.
and
- No ATP is manufactured during the chemical processes occurring in the plant cells.