Question

You take a culture from your mouth and grow it in an incubator. You observe that the cells that grow have introns and branched hydrocarbons in their plasma membranes. What best explains this?

Answer 1

Cells from a culture taken from the mouth with introns and branched hydrocarbons in their plasma membranes suggest they are eukaryotic, with features indicating a past symbiotic event between an Archaeon.

Step-by-step explanation:

The observation that the cells growing from a culture taken from the mouth have introns and branched hydrocarbons in their plasma membranes suggests that these cells are likely eukaryotic rather than prokaryotic. Prokaryotic cells, such as bacteria, generally do not contain introns within their genes, whereas eukaryotic cells do. In addition, the presence of branched hydrocarbons in the plasma membrane is characteristic of Archaea, one of the domains of life alongside Bacteria and Eukaryota. Archaea's membranes are composed of ether-linked lipids, which can differ from the ester-linked fatty acid chains found in bacterial membranes.

This combination of features - introns and branched hydrocarbons - supports the endosymbiotic theory, which posits that eukaryotic cells evolved through a process of genome fusion between an Archaeon and a Bacterium. This theory is furthered by the work of James Lake and the proposed evolution of eukaryotic cells through a symbiotic relationship. The observation correlates with the theory that eukaryotic cells have evolved capabilities from both Archaea and Bacteria, as seen by shared genetic similarities.