I am currently studying Prescott's Microbiology, 10th edition, by Willey, Sherwood, and Woolverton. Chapter 1.2 Microbes Have Evolved and Diversified for Billions of Years presents the following figure:

enter image description here

The authors then ask the question: Why are the probionts pictures above not considered cellular life?

I'm unsure of why the probionts are not considered to be cellular life. If I'm not mistaken, the probionts contained ribozymes, no? This means that they have the capacity to catalyse their own reproduction. And, according to the figure, later probionts also consisted of proteins, so I'm presuming that catalysis and reproduction were not issues here.

I would greatly appreciate it if people would please take the time to clarify this.

  • 1
    $\begingroup$ Welcome to Biology.SE! Please take the tour and then go through the help pages starting with How to Ask questions effectively on this site and edit your question accordingly. In particular, please check out the help on "homework" questions. ——— Also note that whether you consider something "cellular life" depends entirely on how you decide to define "cellular life". Consequently this seems to be more a matter of definition and opinion rather than a fundamentally biological question. Thanks! 😊 $\endgroup$
    – tyersome
    Commented Feb 29, 2020 at 20:03
  • $\begingroup$ This biology.stackexchange.com/a/9455/57068 answered my question. $\endgroup$ Commented Feb 29, 2020 at 23:42


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