Photorespiration – Class 11 | Chapter – 13 | Biology Short Notes Series PDF

Photorespiration: It is a process which involves loss of fixed carbon as  in plants in the presence of light. It is initiated in chloroplasts. This process does not produce ATP or NADPH and is a wasteful process.

Photorespiration is influenced by high temperature as well as light intensity and accelerating the formation of glycolate and the flow through the photorespiratory pathway.

Photorespiration causes a light-reliant acceptance of O2 and discharge of CO2 and is related to the creation and metabolism of a minute particle named glycolate.

Photosynthesis and photorespiration are two biological processes (in flourishing plants) that can function simultaneously beside each other as photosynthesis gives off oxygen as its byproduct and photorespiration gives off carbon dioxide as its byproduct, and the said gases are the raw material for the said processes.

When the carbon dioxide levels inside the leaf dip to about 50 ppm, RuBisCO begins combining Oxygen with RuBP as an alternative to Carbon dioxide.

The final result of this is that as an alternative to manufacturing 2 molecules of 3C- PGA units, merely one unit of PGA is fashioned with a noxious 2C molecule termed phosphoglycolate.

To purge themselves of the phosphoglycolate the plant takes some stepsPrimarily, it instantly purges itself from the phosphate cluster, transforming those units into glycolic acid. After that, this glycolic acid is transferred to the peroxisome and then transformed into glycine. The conversion of glycine into serine takes place in the mitochondria of the plant cell. The serine produced after that is used to create other organic units. This causes a loss of carbon dioxide from the flora as these reactions charge plant’s energy.

Significance of Photorespiration

In C4C4 plants, photorespiration does not occur. This is because these plants have a mechanism that increases the concentration of CO2CO2, at the enzyme site. During the C4C4 pathway, when the C4C4, acid from the mesophyll cells is broken down in the bundle sheath cells, it releases con- this results in increasing the intracellular concentration of CO2CO2. This in turn, ensures that the Rubisco functions as a carboxylase minimising the oxygenase activity. Thus, the productivity and yields are better in CA plants as compared to C4C4, plants. In addition, the C4C4 plants show tolerance to higher temperature also.

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By Team Learning Mantras