2.Cyanobacteria are photosynthetic prokaryotes that are likely responsible for generating theoxygen-rich atmosphere we enjoy on Earth. Many species of cyanobacteria display "circadian rhythms"that manifest as oscillations in gene expression with a period of -24 hours. The circadian rhythms aregoverned by a biochemical cascade that regulates the phosphorylation of a single protein. Remarkably,this circadian "clock" can be reconstituted in vitro with only 3 proteins, known as KaiA, KaiB and KaiC.Upon addition of Mg2+ and ATP to the reaction, Kaic cycles between being phosphorylated anddephosphorylated and reproduces the 24 hour period in the absence of any light cues. In vivo in thecyanobacteria, the phosphorylation of KaiC peaks at night, and this results in the activation of genesencoding components of the oxidative pentose phosphate pathway.DaytimephotosynthesisPSI ROSKaiAKaiBKaicNADPH80ROSco, fixation andBlycogen synthesis+ATP60Detoxification+Mgmechanisms4020ОPPPNADPH244872time (hours)colocooNight-time oxidative pentosephosphate pathway carbon flux(a)reactants and products and enzymes (excluding the final isomerization step).Draw the reactions of the oxidative phase of the pentose phosphate pathway including allOne hypothesis for why the oxidative pentose phosphate pathway is activated at night is to(b)prepare cyanobacteria for the accumulation of reactive oxygen species (ROS) generated during theday by the light-harvesting reactions. Which product of the oxidative pentose phosphate pathway isnecessary to combat reactive oxygen species? What enzyme uses this product to combat ROS andwhat antioxidant does it generate? Which particular ROS does the antioxidant target via a specificenzyme, and what is the enzyme?What other product does the oxidative pentose phosphate pathway produce, what is it used(c)for, and what daytime activity might production of this product prepare cynobacteria for?%P-KaiC

Answer :: An alternative pathway for glucose oxidation is the pentose phosphate pathway (PPP). In…

Cyanobacteria are photosynthetic prokaryotes that are likely responsible for generating the gen-rich atmosphere we enjoy on Earth. Many species of cyanobacteria display "circadian rhythms" manifest as oscillations in gene expression with a period of -24 hours. The circadian rhythms are erned by a biochemical cascade that regulates the phosphorylation of a single protein. Remarkably, circadian "clock" can be reconstituted in vitro with only 3 proteins, known as KaiA, KaiB and KaiC. on addition of Mg²* and ATP to the reaction, KaiC cycles between being phosphorylated and hosphorylated and reproduces the 24 hour period in the absence of any light cues. In vivo in the nobacteria, the phosphorylation of KaiC peaks at night, and this results in the activation of genes oding components of the oxidative pentose phosphate pathway. Daytime photosynthesis KaiA KaiB Kaic ROS NADPH 80 ROS co, fikation and slycogen synthesis +ATP +Mg 60 Detoxification mechanisms 40 20 OPPP NADPH 24 time (hours) 72 Night-time oxidative pentose phosphate pathway carbon flux %P-Kaic

Cyanobacteria are photosynthetic prokaryotes that are likely responsible for generating the gen-rich atmosphere we enjoy on Earth. Many species of cyanobacteria display "circadian rhythms" manifest as oscillations in gene expression with a period of -24 hours. The circadian rhythms are erned by a biochemical cascade that regulates the phosphorylation of a single protein. Remarkably, circadian "clock" can be reconstituted in vitro with only 3 proteins, known as KaiA, KaiB and KaiC. on addition of Mg²* and ATP to the reaction, KaiC cycles between being phosphorylated and hosphorylated and reproduces the 24 hour period in the absence of any light cues. In vivo in the nobacteria, the phosphorylation of KaiC peaks at night, and this results in the activation of genes oding components of the oxidative pentose phosphate pathway. Daytime photosynthesis KaiA KaiB Kaic ROS NADPH 80 ROS co, fikation and slycogen synthesis +ATP +Mg 60 Detoxification mechanisms 40 20 OPPP NADPH 24 time (hours) 72 Night-time oxidative pentose phosphate pathway carbon flux %P-Kaic

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter6: Energy, Enzymes, And Biological Reactions

Section: Chapter Questions

Problem 8TYK: Which of the following statements about the allosteric site is true? a. The allosteric site is a...

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