Some photosynthetic bacteria (e.g., purple sulfur bacteria) have only photosystem I, whereas others (e.g., cyanobacteria) have both photosystem I and photosystem II. Which of the following might this observation imply?
A) Photosystem II was selected against in some species.
B) Photosynthesis with only photosystem I is more ancestral.
C) Photosystem II may have evolved to be more photoprotective.
D) Linear electron flow is more primitive than cyclic flow of electrons.
E) Cyclic flow is more necessary than linear electron flow.
bacteria cell diagram
Periods of Purple Crying
Georgia O'Keeffe, Purple Hills near Abiquiu.
The process of phagocytosis: a phagocyte engulfing bacteria or other foreign material.
The DNA of S-type bacteria can transform R-type bacteria into the same S type.
Bacteria with Internal Membranes