Photorespiration is a wasteful process justify

Do you have any friends who are awesome people, but who also have some kind of bad habit? Maybe they procrastinate a lot, forget your birthday, or never remember to brush their teeth. You wouldn't stop being friends with them for these reasons, yet from time to time, you might find yourself wishing they would clean up their act. RuBP oxygenase-carboxylase ( rubisco), a key enzyme in photosynthesis, is the molecular equivalent of a good friend with a bad habit. In the process of carbon fixation, rubisco incorporates carbon dioxide ( CO 2 \text_2 CO 2 ​ start text, C, O, end text, start subscript, 2, end subscript as a substrate, it sometimes picks up O 2 \text O_2 O 2 ​ start text, O, end text, start subscript, 2, end subscript instead. This side reaction initiates a pathway called photorespiration, which, rather than fixing carbon, actually leads to the loss of already-fixed carbon as CO 2 \text_2 CO 2 ​ start text, C, O, end text, start subscript, 2, end subscript . Photorespiration wastes energy and decreases sugar synthesis, so when rubisco initiates this pathway, it's committing a serious molecular faux pas. As we saw in the introduction, the enzyme rubisco can use either CO 2 \text _2 CO 2 ​ start text, C, O, end text, start subscript, 2, end subscript is the first step of the Calvin cycle and leads to the production of sugar. The reaction that uses O 2 \text O_2 O 2 ​ start text, O, end text, start subscript, 2, end subscript is the first step of the photorespiration...

Photorespiration is the light dependent process of oxygenation of ribulose biphosphate (RuBP) and release of carbon dioxide by the photosynthetic organs of a plant. In the photoresspiratory pathway, there is neither synthesis of sugars nor of ATP Rather , it results in the release of C O 2 ​ with the utilization of ATP Therefore, photorespirtion is a wasteful process.

Simplified photorespiration and Calvin cycle Photorespiration (also known as the oxidative photosynthetic C 2 cycle) refers to a process in 3 plants. The oxygenation reaction of RuBisCO is a wasteful process because 2 While it is common to refer to the entire process as photorespiration, technically the term refers only to the metabolic network which acts to rescue the products of the oxygenation reaction (phosphoglycolate). Photorespiratory reactions [ ] Addition of molecular oxygen to ribulose-1,5-bisphosphate produces Several costs are associated with this metabolic pathway; the production of 3 2, NH 3, and reduces NAD to NADH. Thus, one CO 2 molecule is produced for every two molecules of O 2 (two deriving from RuBisCO and one from peroxisomal oxidations). The assimilation of NH 3 occurs via the Substrate specificity of RuBisCO [ ] The oxidative photosynthetic carbon cycle reaction is O 2 → Phosphoglycolate + H + During the catalysis by RuBisCO, an 'activated' intermediate is formed (an enediol intermediate) in the RuBisCO active site. This intermediate is able to react with either CO 2 or O 2. It has been demonstrated that the specific shape of the RuBisCO active site acts to encourage reactions with CO 2. Although there is a significant "failure" rate (~25% of reactions are oxygenation rather than carboxylation), this represents significant favouring of CO 2, when the relative abundance of the two gases is taken into account: in the current atmosphere, O 2 is approxi...

Photorespiration, as the name suggests is the process by which the most abaundant protein on earth, RubisCO, uses up oxygen or adds oxygen to the 5 carbon sugar rubisco bisphosphate, instead of carbon dioxide as in the process of photosynthesis. It is the alternate pathway used by the enzyme. This enzyme being both a carboxylase and an oxygenase does not have the capability to differentiate between the carbon dioxide molecule or the oxygen molecule as a result of which it can assist in both the reaction of photorespiration and photosynthesis, even though they are the opposite pathways. In general RubisCO favours carbon dioxide to oxygen, and approximately 3 carboxylations occur per oxygenation. It is interesting to note that photorespiration only occurs in C3 plants where the oxygenase plays its role. It is important because it is a major source of H2O2 in photosynthetic cells. Through H2O2 production and pyridine nucleotide interactions, photorespiration makes a key contribution to cellular redox homeostasis. Get original paper Without paying upfront In so doing, it influences multiple signaling pathways, particularly those that govern plant hormonal responses controlling growth, environmental and defense responses, and programmed cell death Photorespiration occurs when carbon dioxide levels within the leaf tissue dwindle to about 50 parts per million, usually on a hot, dry day where a plant has closed its stomates to prevent water loss. At this concentration of CO2, oxyg...