Read the given paragraph.
Photosynthesis in plants consists of two phases: P and Q. Phase P requires light energy and occurs in grana region of chloroplast whereas phase is light independent and occurs in stroma of chloroplast Which of the following holds true regarding phases P and Q of photosynthesis?

Options

A. In phase Q , light energy is used up in photolysis of water and molecular oxygen is evolved .
B. Phase Q utilises assimilatory power produced during P Phase
C. Phase P is influenced by temperature wherease phase Q is not affected by changes in temperature .
D. Phase P utilise carbon dioxided gas of atmosphere whereas phase Q evolves oxygen gas the escapes into atmosphere .

Answer

To solve the question regarding the phases of photosynthesis, we need to analyze the information provided in the paragraph and the video transcript step by step.

### Step-by-Step Solution:

1. **Identify the Phases of Photosynthesis**:
- The paragraph states that photosynthesis consists of two phases: Phase P and Phase Q.
- Phase P is described as requiring light energy and occurring in the grana region of the chloroplast.
- Phase Q is described as light-independent and occurring in the stroma of the chloroplast.

2. **Understand the Functions of Each Phase**:
- Phase P (Light Phase): This phase involves the absorption of light energy, which is used to split water molecules (photolysis) and produce energy-rich molecules like ATP and NADPH.
- Phase Q (Dark Phase): This phase does not directly require light. It utilizes the energy-rich molecules (ATP and NADPH) produced in Phase P to convert carbon dioxide into glucose through the Calvin cycle.

3. **Analyze the Given Options**:
- **Option A**: "In phase Q, light energy is used up in photosynthesis of water and molecular oxygen is involved."
- This is incorrect because photolysis of water occurs in Phase P, not Q.
- **Option B**: "Phase Q utilizes assimilatory power produced during P phase."
- This is correct. Phase Q uses the ATP and NADPH produced in Phase P.
- **Option C**: "Phase P is influenced by temperature whereas phase Q is not affected by changes in temperature."
- This is incorrect. Both phases can be influenced by temperature, although Phase Q may be less affected.
- **Option D**: "Phase P utilizes carbon dioxide."
- This is incorrect. Carbon dioxide is primarily utilized in Phase Q.

4. **Conclusion**:
- The correct statement regarding phases P and Q of photosynthesis is **Option B**: "Phase Q utilizes assimilatory power produced during P phase."

### Final Answer:
Option B is the correct answer.

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