Respuesta :
Glycolysis, pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation, using an electron acceptor other than oxygen are the catabolic processes may have been used by cells on ancient earth before free oxygen became available.
How was earth before oxygen?
- The rise of oxygen occurred slowly, over many millions of years.
- Jay Kaufman, a geoscientist at the University of Maryland, points to a series of ice ages'—at least three of them'—that occurred between 2.4 billion and a couple of 2 billion years ago, when the age of oxygen began. Life, Kaufman et al. suspect, may are partly responsible for these periods of cooling.
- Even as microbes were busy generating oxygen, they drew CO₂ from the atmosphere, perhaps thinning Earth's blanket of warmth; the oxygen they produced reacted with methane, reducing another greenhouse emission .
- The resulting glacial period may in turn have reduced microbial activity, allowing CO₂ emitted by volcanoes to again build up and the planet to again warm. This cycle may have occurred a minimum of three times, whenever resulting in a slightly higher level of atmospheric oxygen.
- But, as Kaufman emphasizes, much remains unknown about these periods of glaciation, and therefore the work of many researchers will be required to shed further light on this era.
- "I would hypothesize that the connection of the ice ages with atmospheric chemistry is biological," Kaufman says. "We do know that biology can affect the atmosphere. And if biology drew greenhouse gases out of the atmosphere, it could end in those ice ages and the rise of oxygen gas."
To learn more about Glycolysis: https://brainly.com/question/14076989
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