key term - 2-phosphoglycolate

Definition

2-phosphoglycolate is a two-carbon molecule that serves as a key intermediate in the process of photorespiration, primarily formed when ribulose-1,5-bisphosphate reacts with oxygen instead of carbon dioxide. This compound is crucial for understanding the inefficiencies in photosynthesis, as its formation can lead to the loss of fixed carbon and energy, ultimately impacting plant growth and productivity.

5 Must Know Facts For Your Next Test

1. 2-phosphoglycolate is produced when RuBP reacts with oxygen in a process facilitated by the enzyme RuBisCO, leading to a competitive inhibition of carbon fixation.
2. The presence of 2-phosphoglycolate indicates a shift towards photorespiration, which can be detrimental to the efficiency of photosynthesis under high oxygen and low carbon dioxide conditions.
3. In plants, 2-phosphoglycolate is eventually converted into glycolate before entering further metabolic pathways to salvage some of the carbon lost during photorespiration.
4. Photorespiration is more pronounced in C3 plants, which lack the adaptations found in C4 and CAM plants that minimize the formation of 2-phosphoglycolate.
5. Understanding the dynamics of 2-phosphoglycolate is essential for developing strategies to enhance photosynthetic efficiency and crop yields under changing environmental conditions.

Review Questions

• How does the formation of 2-phosphoglycolate affect the efficiency of photosynthesis in plants?
  • The formation of 2-phosphoglycolate affects photosynthesis efficiency by diverting ribulose-1,5-bisphosphate from its intended reaction with carbon dioxide to react with oxygen instead. This results in photorespiration, a process that consumes energy and releases fixed carbon, ultimately lowering the net gain of carbohydrates during photosynthesis. Consequently, plants experience reduced growth and productivity due to this inefficient pathway.
• Discuss the role of RuBisCO in the production of 2-phosphoglycolate and its implications for plant metabolism.
  • RuBisCO plays a pivotal role in the production of 2-phosphoglycolate as it catalyzes the reaction between ribulose-1,5-bisphosphate and both carbon dioxide and oxygen. While it facilitates carbon fixation under normal conditions, its tendency to react with oxygen under certain environmental stresses leads to the formation of 2-phosphoglycolate. This not only signifies inefficiencies in plant metabolism but also necessitates additional pathways for recycling carbon, illustrating a balance between photosynthesis and photorespiration.
• Evaluate the potential strategies that could be employed to mitigate the negative effects of 2-phosphoglycolate on plant productivity.
  • To mitigate the negative effects of 2-phosphoglycolate on plant productivity, strategies could include genetic engineering to enhance RuBisCO specificity for carbon dioxide over oxygen or introducing pathways from C4 plants into C3 plants to minimize photorespiration. Additionally, optimizing environmental conditions such as CO2 concentration and temperature could help reduce the incidence of photorespiration. By addressing these factors, researchers aim to improve overall photosynthetic efficiency and increase crop yields, particularly in regions facing climate change challenges.

Related terms

Photorespiration:

A metabolic process in plants where oxygen is consumed and carbon dioxide is released, often considered a wasteful pathway that occurs alongside photosynthesis.

Ribulose-1,5-bisphosphate (RuBP): A five-carbon sugar that is a substrate in the Calvin cycle; it reacts with carbon dioxide during photosynthesis to form 3-phosphoglycerate.

Carbon Fixation: The process of converting inorganic carbon (CO2) into organic compounds by living organisms, primarily occurring during photosynthesis.