Which pair is wrong?

Question

Accepted Answer

The correct option is 1:

The pair "C3 Maize" is wrong because Maize (corn) is a classic example of a C4 plant, not a C3 plant. C4 plants have a specialized photosynthetic pathway that allows them to efficiently fix carbon dioxide in hot, dry environments, which is characteristic of where maize typically grows. Their photosynthetic machinery is adapted to minimize photorespiration, a process that reduces photosynthetic efficiency in C3 plants. Therefore, associating maize with the C3 pathway is incorrect.

The incorrect option is 2:
The pair "Calvin cycle....PGA" is correct. The Calvin cycle, also known as the C3 pathway, is the primary set of light-independent reactions in photosynthesis. During this cycle, carbon dioxide is fixed, and the first stable product formed is a 3-carbon compound called 3-phosphoglycerate (PGA). This is a fundamental aspect of C3 photosynthesis.

The incorrect option is 3:
The pair "Hatch and Slack cycle....OAA" is correct. The Hatch and Slack cycle is the C4 pathway of photosynthesis. In this pathway, carbon dioxide is initially fixed into a 4-carbon compound, oxaloacetate (OAA), in the mesophyll cells before being transferred to bundle sheath cells for the Calvin cycle. This initial carbon fixation into OAA is a defining feature of the C4 pathway.

The incorrect option is 4:
The pair "C4....Kranz anatomy" is correct. Kranz anatomy is a distinctive anatomical feature found in the leaves of C4 plants. It is characterized by a wreath-like arrangement of bundle sheath cells around the vascular bundles, which are rich in chloroplasts and facilitate the efficient operation of the Hatch and Slack cycle. This specialized anatomy is crucial for the C4 photosynthetic mechanism.