Lab 7 Exploring Photosynthesis Post-Lab Assignment PDF

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exploring photosynthesis post-lab assignment for lab 7...

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BIOL-1500 1 November 2021 Lab 7: Exploring Photosynthesis Post-Lab Assignment 1. During Photosynthesis, DPIP presents itself as an electron accepter. When the electron is accepted, the cuvettes will turn clear, which allows the light transmittance levels to be measured to figure out the rate of photosynthesis. When light strikes chloroplasts, electrons boosted to high energy levels will reduce DPIP. It will change from blue to colorless (Nguyen et al., 2021).

2. DPIP is the molecule that replaces NADP+.

3. H2O is the source of the electrons that reduced the DPIP.

4. What was measured with the spectrophotometer in this experiment was the light transmittance levels, which will tell the photosynthesis is taking place.

5. If the light source used only shone green light, this means that the chloroplast caused the green light to be reflected. This is so because the light would have been limited, so the plant would not be able to undertake photosynthesis. Also, remember that chloroplast can only absorb (colors) on a spectrum.

6. The live chloroplast was expected to carry out photosynthesis when they are incubated because the source of energy was the lamp (light), which would present a transmittance

that is high. The chloroplast that remained in the dark, were not supposed to carry out photosynthesis because there was no source of light, and obviously no transmittance.

Results:

Discussion: During Photosynthesis, DPIP presents itself as an electron accepter. When the electron is accepted, the cuvettes will turn clear, which allows the light transmittance levels to be measured to figure out the rate of photosynthesis. When light strikes chloroplasts, electrons boosted to high energy levels will reduce DPIP. It will change from blue to colorless (Nguyen et al., 2021). When the chloroplast was extracted and incubated with the DPIP in the presence of the lamp, the DPIP

becomes colorless and reduced, which results in an increase of the transmittance over time (0-15 minutes). My hypothesis was that the light and the chloroplast will cause a change in the rate of transmittance. My null hypothesis is that the light and the chloroplast will not cause a change in the rate of transmittance. I did find it odd that cuvette 4 (boiled/light) remained constant. Meaning that from 0-15 minutes the transmittance remained at 125.9%, when cuvette 5 (no chloroplast) remained at 125.9% as well, but it did not contain any chloroplast. An error could have occurred if the data was read incorrectly, if the boiled was incubated in the dark instead of the light, or if cuvette 5, which contained no chloroplast, were to have chloroplast instead. The reason why certain conditions experienced greater/lesser photosynthesis activity was due to the fact of whether the cuvettes were placed in a light source or not.

Work Cited: Nguyen, J., Mertzlufft, D., Koerner, S., Corneille, K., Raja, A., & Schmitt Lavin, E. (2021). Biology 1500 Laboratory Manual (2nd ed.). Morton Publishing Company....