Besides carboxylation, the Calvin Cycle enzyme rubisco can also react with O2 (e.g. oxygenation). The wasteful oxygenation reaction of rubisco is explained by the enzyme developing at time when there was very little O2 in the atmosphere. Since it was developed, why hasn’t rubisco evolved to get rid of the oxygenation reaction? A. Mutations that decrease the affinity of rubisco for O2 probably also decrease the enzyme’s ability to bind CO2. B. Evolution takes time; and since rubisco is found only in eukaryotes, it evolved recently. C. Since it still generates one molecule of 3-phosphoglycerate (PGA), the oxygenation reaction is actually not that wasteful. D. Because in the past few million years the concentration of CO2 in the atmosphere has risen to be much greater than the concentration of O2.

Rubisco is a key enzyme in photosynthesis. It is a molecular equivalent of a good friend with a bad…

Besides carboxylation, the Calvin Cycle enzyme rubisco can also react with O2 (e.g. oxygenation). The wasteful oxygenation reaction of rubisco is explained by the enzyme developing at time when there was very little O2 in the atmosphere. Since it was developed, why hasn’t rubisco evolved to get rid of the oxygenation reaction?

Besides carboxylation, the Calvin Cycle enzyme rubisco can also react with O2 (e.g. oxygenation). The wasteful oxygenation reaction of rubisco is explained by the enzyme developing at time when there was very little O2 in the atmosphere. Since it was developed, why hasn’t rubisco evolved to get rid of the oxygenation reaction?

Concepts of Biology

1st Edition

ISBN:9781938168116

Author:Samantha Fowler, Rebecca Roush, James Wise

Publisher:Samantha Fowler, Rebecca Roush, James Wise

Chapter5: Photosynthesis

Section: Chapter Questions

Problem 13CTQ: Why are carnivores, such as lions, dependent on photosynthesis to survive?

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Similar questions

Why would nature evolve a key enzyme, rubisco, that is so sensitive to oxygen, resulting in photorespiration?
Explain the following observation. When a photosynthetic system is exposed to a brief flash of light, no oxygen is evolved. Only after several bursts of light is oxygen evolved.
Why are carnivores, such as lions, dependent on photosynthesis to survive?
What is the origin of oxygen on earth? What would happen to earth’s supply of oxygen if photosynthesis suddenly were to cease?
Which of the following statements is MOST ACCURATE? A. The oxidation of NADH in the mitochondrial matrix results in the transfer of 1 electron to the electron transport chain. B. The reduction of NADH in the mitochondrial matrix results in the transfer of 1 electron to the electron transport chain. C. The reduction of NADH in the mitochondrial matrix results in the transfer of 2 electrons to the electron transport chain. D. The oxidation of NADH in the cytoplasm results in the transfer of 1 electron to the electron transport chain. E. The oxidation of NADH in the mitochondrial matrix results in the transfer of 2 electrons to the electron transport chain.
Human beings do not produce energy by photosynthesis, yet this process is critical to our survival. Explain
If a mutation occurs such that photosystem II no longer functions as efficiently as it should, which of the answer choices would be most directly affected? the amount of O2 produced the rate at which NADPH is produced the rate at which protons are transported into the thylakoid the rate of ATP synthesis by ATP synthase in the chloroplast
In addition to the pigments commonly associated with photosynthesis, a certain photosynthetic species contains two additional pigment types. Which of the following best supports the claim that this species is better adapted to environmental changes than other photosynthetic species are? a) The additional pigments allow the species to outcompete other species for the wavelengths of light commonly used in photosynthesis. b) The increased pigment concentration better facilitates energy production within the cells of the species. c) The pigment combination allows the organism to absorb heat as well as light, making better use of available energy. d) The additional pigments allow the species containing them to harvest energy from wavelengths of light that the other photosynthetic species cannot use.
During oxygenic photosynthesis in eukaryotes, which substrate molecules provide the oxygen atoms that end up in product glucose molecules? CO2 only H2O and C6H12O6 only H2O only C6H12O6 and O2 only O2 only
Which of the following is an incorrect statement about the Calvin cycle? A.The main inputs to the reactions are NADPH, ATP, and CO2. B.The main outputs of the reactions are NADP+ , ADP, and sugar. C.More NADPH is used than ATP during the Calvin cycle. D.Carbon fixation is the first step of the process
What Is The Main Purpose Of Oxygen In Cellular Respiration? A)Allowing For The Break Down Of Glucose In Pyruvate B)Suppling Electrons To The Electron Transport Chain C)Allowig For A Flow Of Electrons In The Electron Transport Chain D)Oxidation Of Pyruvate To Acetyl COA
How are the processes of cellular respiration and photosynthesis related? The carbon molecules in glucose are converted to what molecule during respiration? What happens to the carbon dioxide molecules plants use in photosynthesis? Do plants have both chloroplasts and mitochondria? Why would this be?