Experiment 10 - Photosynthesis Flashcards
Run the experiment with all values in their “starting” position. Notice that ATP and NADH concentration increases and decreases at a regular rate over time. Explain the relationship between these regular increases and decreases and the production of glucose. (document this)
The interplay between ATP and NADH levels is tightly regulated to ensure proper glucose production. When the energy status of the cell is high (indicating abundant ATP), the production of glucose via gluconeogenesis is favored. This is because the availability of ATP allows energy-consuming reactions to proceed. Conversely, when ATP levels are low, gluconeogenesis is inhibited as there may not be enough energy to support the process.
Similarly, the levels of NADH also influence gluconeogenesis. An increase in NADH levels inhibits the conversion of pyruvate to glucose. This is because the conversion of pyruvate to glucose requires NADH to be converted back to NAD+, and an excess of NADH signals that energy needs are being met and glucose production is not necessary.
In summary, the relationship between the regular increases and decreases of ATP and NADH with the production of glucose is based on the energy needs of the cell. ATP provides the energy required for gluconeogenesis, while NADH levels influence the availability of reducing equivalents for the conversion of pyruvate to glucose. The interplay between these molecules ensures that glucose production is regulated in response to the energy status of the cell.
you compare glucose production in this situation to the ideal settings from challenge # 1 you will see gluvose is only produced at one time, at just after 30 minutes. This is because the photosystems involved in photosynthesis respond to a wide range of light wavelengths, not just a single wavelength. However, enough energy must be available at this wavelength to slowly produce glucose. Play around the variables (except wavelength of light) and identify one way to change the environment that will produce glucose at a faster rate. (document this)
Identify the variable you manipulated that increases the rate of glucose production.
We can manipulate added NADPH (µmol) to increase the rate of glucose production.
Explain why that variable increases the glucose rate of production.
NADPH serves as a crucial electron donor in the Calvin cycle, which is the light-independent phase of photosynthesis responsible for glucose synthesis. In the Calvin cycle, carbon dioxide is fixed and reduced to produce glucose. The reducing power provided by NADPH is essential for the reduction of carbon dioxide into carbohydrate molecules.
By adding NADPH to the system, we can increase the availability of the reducing power required. This can enhance the rate of glucose production. With more NADPH available, the enzyme responsible for the reduction of carbon dioxide, called ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), can function more efficiently. Rubisco uses NADPH and ATP (produced during the light-dependent reactions) to convert carbon dioxide into sugar molecules, including glucose.
By increasing the supply of NADPH, we provide additional reducing power to fuel the Calvin cycle, which leads to an increased production of glucose.
