Structural Differences in Distinct Classes of Cells
Thus far we have been describing the structure and function of
eukaryotic animal
cells. As we have mentioned earlier, there are different classes of
cells. In this short section, we will discuss the major cellular differences
between
prokaryotic
and eukaryotic cells, and between animal and plant cells. The diversity
among various cells is a result of the varying functions and complexity of those cells.
Because plants convert sunlight into energy rather than obtaining energy by
eating food the way we humans do, plant cells require additional structures that
can perform this function. While most structures between animal and plant cells
are the same, there are a couple of additional structures that perform specific
functions in plant cells that are unnecessary in animal cells.
In contrast to eukaryote cells, prokaryotic cells lack membrane-bound
organelles. Such
organization is necessary in eukaryotic cells because
eukaryotes are often multi-cellular organisms whose cells communicate with the
help of specific membrane-bound structures. Because prokaryotic cells do not
form such complex networks, a single compartment containing all of the essential
biomolecules for life is sufficient.
We will begin our discussion by contrasting plant and animal cells and then move
on to the structural differences between prokaryotic and eukaryotic cells.