In most hypotheses of early earth and the formation of life, it is accepted that the atmosphere was a reducing one. this means that there was an abundance of methane, ammonia, and water vapor, but there was an absence of significant amounts of oxygen gas. based on this assumption, what was likely the first metabolic activity to harness atp to evolve in primitive cells?

The first metabolic activity for ATP synthesis would be glycolysis.

Explanation:

The process of glycolysis does not require oxygen and it generates ATP. The Earth, in the beginning, did not possess enough free oxygen for respiration. This is the reason we can assume that the earliest forms of life were heterotrophic and not autotrophic.

Glycolysis is a process that is involved in fermentation and the process does not require oxygen. However, the process of glycolysis can produce only two molecules of ATP.

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