Difference between C3 and C4 Plants | Photorespiration

The upcoming discussion will update you about the difference between c₃ plants and c₄ plants.

Difference # C₃ Plants:

1. CO₂ acceptor is RuBP (Ribulose bisphosphate).

2. Only one type of chloroplasts occur in the cells. Grana present in chloroplasts.

3. First stable compound after CO₂ fixation is PGA.

4. Plants photosynthesize well, if CO₂ concen­tration is high.

5. They possess photorespiration that results in a low overall efficiency in synthesis of carbo­hydrates.

6. Excess of atmospheric oxygen inhibits photo­synthetic activity.

Difference # C₄ Plants:

1. CO₂—acceptor is PEP (Phosphoenol pyruvate).

2. Two types of chloroplasts, bundle sheath chlo­roplasts possess C₃ cycle (Calvin cycle) and do not have grana; and mesophyll chloroplasts pos­sess C₄ cycle (Hatch Slack cycle), and have grana.

3. First stable compound after CO₂ fixation is oxaloacetate.

4. Plants synthesize well, even if CO₂ concentra­tion is low.

5. They lack photorespiration and conserve more or­ganic food and thus an overall higher photosyn­thetic efficiency.

6. Excess of atmospheric oxygen has no effect on photosynthesis.