Answer:
in the lumen of the thylakoid
Answer:
Similarity of structures due to common ancestry is called homology.
Explanation:
Homology is the relationship that exists between two different organic parts when their genetic determinants have the same evolutionary origin or a common ancestry, that is, it is a feature or characteristic that is shared by all descendants of a common ancestor, and not shared with other groups. For example, the arrangement and structure of limbs in vertebrates are similar, these similarities then come from a common ancestor to all vertebrates.
Most important and abundant one are the phospholipids - amphiphatic molecules with an hydrophilic head and a hydrophobic hydrocarbon tails. They compose the membrane bilayer. Also important are the membrane proteins, which can be periheric and internal and can serve as channels, receptors, pumps etc.
Depending on the cell type the membrane can also contain cholesterol (in animal cells, enhances the membrane stability) or hopanes(in prokaryotes, same function as cholesterol) or ether-phospholipids with branched hydroharbon tails(in archaea, make the membranes more stable and resistant to severe conditions, as archaeas are extremophiles)
The Human Respiratory system.
