I think that the enclosure of self-replicating RNA in a phospholipid membrane. The first cell is thought to have arisen by the enclosure of self-replicating RNA and associated molecules in a membrane composed of phospholipids.
I’m unsure how to answer this because I don’t know How much bacteria there was What bacteria it was And what the conditions of the bacteria are This chart is from Dr. Jason from the math forum http://mathforum.org/library/drmath/view/64555.html hope this helps!