Maternal and fetal tissues form two units that are closely bound together at the placental level. Quiz. The fetal part of the placenta is made up of the chorionic plate with its placental villi, the cytotrophoblast layer and the intervillous spaces.
1 , which performs the function of photosynthesis. 2  Chloroplasts are double-membrane-bound, like mitochondria. 3  Also like mitochondria, their inner membrane is very complicated. 4  In fact, it's formed into many thylakoid structures which perform the same function performed by the thylakoids in prokaryotic cells.
Prokaryotes, of course, lack spindles and centrioles; the cell membrane assumes this function when it pulls the by-then replicated chromosomes apart during binary fission. Cells that contain centrioles also have a series of smaller microtubules, the aster, that extend from the centrioles to the cell membrane.