Proton pumps are used in various ways by members of every domain of organisms: Bacteria, Archaea, and Eukarya. What does this most probably mean?
A) Proton pumps must have evolved before any living organisms were present on Earth.
B) Proton gradients across a membrane were used by cells that were the common ancestor of all three domains of life.
C) The high concentration of protons in the ancient atmosphere must have necessitated a pump mechanism.
D) Cells of each domain evolved proton pumps independently when oceans became more acidic.
E) Proton pumps are necessary to all cell membranes.
Antifreeze in living organisms
Organisms exhibit a diversity of behaviours, which include (clockwise from upper left), foraging and
A plot of trophic diversity across the major groups of organisms shows highest trophic diversity amo
Different ways to depict phylogenetic relationships
) A more elaborate motif, the β barrel. This β barrel is a single domain of α-hemolysin
Seven black members of Congress in 1871 are from left to right: Senator Hiram Revels (R-MS) and Repr