Question

What happens to the enzyme RuBisCO during photorespiration?

Answer 1

Photorespiration:

1. It is a process in which plants lose fixed carbon as CO₂ in the presence of light.
2. It begins in chloroplasts.
3. This is a wasteful process that does not produce ATP or NADPH.
4. When there is a high quantity of oxygen, photorespiration occurs.

RuBisCO:

1. RuBisCO is an oxygenase that catalyzes the carboxylation of RuBP during the first step of the Calvin cycle.
2. Because some O₂ binds to RuBisCO, CO₂ fixation is reduced.
3. It is the most prevalent protein in nature.
4. RuBisCO is dormant in the dark and activates in the light.
5. RuBisCO is found in algae, photosynthetic protists, plants, and some autotrophic bacteria including cyanobacteria and proteobacteria.

Role of RuBisCo during photorespiration:

1. In the photorespiration pathway, RuBP binds to O₂ to create one molecule of PGA (3C chemical) and phosphoglycolate (2C compound).
2. There is no sugar synthesis or ATP synthesis.
3. Rather, it results in the emission of CO₂ as a result of the use of ATP. It results in a 25% reduction in stationary CO₂ emissions.