3. (2pts) Photosynthesis is a redox reaction. In the light-reaction of photosynt

Question

3. (2pts) Photosynthesis is a redox reaction. In the light-reaction of photosynthesis, molecule is oxidized? I reduced? what n the dark-reaction (Calvin Cycle) of photosynthesis, what molecule is 4. (2pts) In the Hill Reaction (not photosynthesis), what would you expect to happen to absorbance when the test tube is exposed to light? Would it increase, decrease, or stay the same? Why? 5. (2pts) In the Hill Reaction (not photosynthesis), what would you expect to happen to absorbance if the test tube is NOT exposed to light? Would it increase, decrease, or stay the same? Why?

Explanation / Answer

3) Chloroplast is involved in photosynthesis and it takes place in thylakid discs. In the light reaction, water is oxidized and oxygen is released. The electrons which were released from water are transferred to ATP and NADPH. And In Calvin cycle, the electrons released by oxidation of NADPH would be used to reduce CO2 to sugar (G3P) which then exits in Calvin cycle.

4 and 5)

Hills reaction demonstrates that isolated chloroplasts from plants can release oxygen when illuminated by sunlight in the prescence of suitable electron acceptor. To demonstrate this, Hills reagent was demonstrated where DCPIP (dichlorophenolindphenol) was used as terminal electron acceptor replacing NADP. Hill's reaction is described as light dependent reaction of photosynthesis where it confirms that Oxygen is produced by reaction that is separate from carbon doixide fixation.

In the lab experiment, absrbace reading measured DCPIP oxideized in the cells.As photosynthesis occurs, electrons were donated to DCPIPoxidized forming DCPIPH2reduced. As photosynthesis occurs, there would be less and less DCPIPoxidized available for absorbance. This is the reasn why when exposed to light, absorbances would decrease and when the test tubes were NOT exposed to light, the absorbances would remain constant. Though the test tubes heats up, there wasnt enough light to make DCPIP reduce so the absorbances wouldnt change.

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.