Question

Correctly match the photosynthetic pathways (Group I) with their first stable products (Group II) in respective plants (Group III):

• A. P-1-a; Q-3-b; R-3-c
• B. P-1-a; Q-2-b; R-3-c
• C. P-1-b; Q-3-a; R-2-c
• D. P-1-b; Q-2-c; R-2-a

Hint:

The first stable products in photosynthesis vary depending on the pathway. C3 plants form 3-Phosphoglycerate, C4 plants form Oxaloacetate, and CAM plants also initially form Oxaloacetate, but with a temporal separation of CO2 fixation.

Answer 1

The Correct Option is A

Let’s go through the photosynthetic pathways and their first stable products in respective plants: 
- (P) C3 cycle: In C3 plants such as wheat (Group III, a), the first stable product formed in the Calvin cycle is 3-Phosphoglycerate (Group II, 1). This is characteristic of the C3 cycle, where CO2 is fixed into 3-Phosphoglycerate, making the correct match \( P-1-a \). 
- (Q) C4 cycle: In C4 plants like sugarcane (Group III, b), the first stable product formed during the initial fixation of CO2 is Oxaloacetate (Group II, 3). This occurs before the further processing of Oxaloacetate into other intermediates, making the correct match \( Q-3-b \). 
- (R) CAM: In CAM plants like pineapple (Group III, c), the first stable product formed is Oxaloacetate (Group II, 3) during the initial fixation of CO2 at night when stomata are open. Therefore, the correct match is \( R-3-c \). 
Thus, the correct answer is (A), as the correct matching for the first stable products in the respective plants is \( P-1-a \), \( Q-3-b \), and \( R-3-c \).