Unlike eukaryotic
cells, prokaryote
cells lack membrane-bound
organelles.
However, whereas prokaryote cells are less structurally complex
than eukaryotes, they are more chemically complex, since all of the prokaryote
cell's biomolecules are floating around together. These biomolecules must
interact only with other appropriate molecules to perform biological function.
Prokaryotic cells contain a single compartment enclosed within the cell
membrane. In this space reside DNA, RNA, ribosomes and other molecules.
Prokaryotes lack a defined
nucleus (which is
where DNA and RNA are stored in
eukaryotic cells),
mitochondria,
ER, golgi
apparatus, and so
on. In
addition to the lack of organelles, prokaryotic cells also lack a
cytoskeleton.
Recall that in addition to its role as structural support for
the interior of the cell, the cytoskeleton is also involved in intracellular
organelle transport. Since there are no organelles to be transported in
prokaryotic cells, such a function is unnecessary.
Like the eukaryote cell, the prokaryote cell is filled with
cytosol. The
prokaryote cytosol is filled with enzymes, which carry out respiratory processes
reserved in eukaryotes for the mitochondria. Prokaryote and eukaryote ribosomes
also differ slightly, reflect minor
differences in prokaryotic versus
eukaryotic processing of DNA.
