NEETBotanyPhotosynthesis in Higher Plants
What happens to C4 acids in the bundle sheath cells?
Options
- AThey are converted to RuBP.
- BThey are broken down to release CO2 and a 3-carbon molecule.
- CThey are stored as starch.
- DThey are used directly in the Calvin cycle.
Correct answer
B. They are broken down to release CO2 and a 3-carbon molecule.
Step-by-step solution
The C4 acid OAA is formed in the mesophyll cells. It then forms other 4-carbon compounds like malic acid or aspartic acid in the mesophyll cells itself, which are transported to the bundle sheath cells. In the bundle sheath cells these C4 acids are broken down to release CO2 and a 3-carbon molecule . The 3-carbon molecule is transported back to the mesophyll where it is converted to PEP again, thus, completing the cycle. It then forms other 4-carbon compounds like malic acid or aspartic acid in the mesophyll cells