Question

Give the ratios between the following compounds in photosynthesis of plants: 
A. Tetroses and sedoheptuloses 
B. CO2 fixed and net production of G-3-P 
C. DHAP takes part in regenerative phase and RUBP formed

• A. A-5:1, B-3:1, C=2:3
• B. A-3:2, B-1:2, C-3:4
• C. A-1:5, B-1:3, C-3:2
• D. A-2:4, B-3:4, C-3:2

Hint:

Detailed understanding of the Calvin cycle and its intermediates is essential for grasping how plants synthesize and recycle molecules during photosynthesis.

Answer 1

The Correct Option is A

Step 1: The ratio of tetroses to sedoheptuloses in photosynthesis is approximately 5:1. This is because during the Calvin cycle, carbon atoms are sequentially transferred between different sugar intermediates, and the ratio of tetroses to sedoheptuloses is crucial for the regeneration of RUBP.
Step 2: The ratio of CO2 fixed to the net production of G-3-P (Glyceraldehyde-3-phosphate) is generally 3:1. This is because for every 3 molecules of CO2 fixed, one molecule of G-3-P is produced in the Calvin cycle. This ensures a balance between carbon fixation and the production of energy-rich molecules for plant growth. 
Step 3: DHAP (Dihydroxyacetone phosphate) is involved in the regenerative phase of the Calvin cycle. It helps in the regeneration of RUBP (Ribulose bisphosphate), and the ratio of DHAP to RUBP formation is about 2:3. This is essential for maintaining the cycle's continuity and for further CO2 fixation. 
Conclusion: The correct ratios are: - A-5:1, - B-3:1, - C-2:3.