Which two energy compounds are transferred to the Calvin cycle during photosynthesis?

• A. $\mathrm{ATP}$ and ${\mathrm{FADH}}_2$
• B. $\mathrm{ATP}$ and ${\mathrm{NADPH}}_{\mathrm{}}$
• C. $\mathrm{ADP}$ and ${\mathrm{NADH}}_{\mathrm{}}$
• D. ${\mathrm{FADH}}_2$ and ${\mathrm{NADPH}}_{\mathrm{}}$

Answer: (B)

Verified step by step guidance

1. Understand the context of the problem: The Calvin cycle is a part of photosynthesis where energy compounds are used to convert carbon dioxide into glucose.
2. Identify the role of ATP and NADPH in the Calvin cycle: ATP provides energy, while NADPH provides reducing power (electrons) necessary for the conversion of 3-phosphoglycerate into glyceraldehyde-3-phosphate.
3. Recognize the difference between NADPH and NADH: NADPH is used in anabolic reactions, such as photosynthesis, whereas NADH is typically involved in catabolic reactions, such as cellular respiration.
4. Consider the role of FADH2: FADH2 is primarily involved in cellular respiration, not photosynthesis, and is not used in the Calvin cycle.
5. Conclude that ATP and NADPH are the correct energy compounds transferred to the Calvin cycle during photosynthesis, as they are specifically involved in the energy and electron transfer processes required for the cycle.