Which statement most closely expresses our present understanding?
A) The chloroplast and the cyanobacteria are not closely (or specifically) related.
B) The chloroplast arose from within the cyanobacterial phylum.
C) The chloroplast is a descendent of the cyanobacteria.
D) The cyanobacteria are descendents of the chloroplast.

Question

Quizplus · Accepted Answer

The most widely accepted theory is that the chloroplast arose from endosymbiosis, where a eukaryotic cell engulfed a cyanobacterium and the two evolved into a single organism. This theory is supported by various pieces of evidence, such as the presence of a double membrane around the chloroplast, the similarity in the photosynthetic machinery of chloroplasts and cyanobacteria, and the fact that both contain their own circular DNA. However, it is important to note that the chloroplast and contemporary cyanobacteria are not the same and have likely diverged significantly since their initial symbiotic relationship.

Which Statement Most Closely Expresses Our Present Understanding