Plant Cells and Animal Cells - Essay Example

Plant and animal cells each have a true nucleus because they are both eukaryotic organisms.  This central membrane-bound compartment is the site of storage for most of the cell’s genetic material.  Within the nucleus, there is a nucleolus that produces ribosomes.  Likewise, both plant and animal cells have corresponding organelle structures with identical functions.   This includes the rough endoplasmic reticulum, smooth endoplasmic reticulum, peroxisomes, lysosomes, Golgi bodies, secretory vesicles, mitochondria, microtubules and microfilaments, cell membrane, cytosol, and a centrosome. 

Both plant cells and animal cells have an organelle known as the vacuole, but there are major functional differences between an animal vacuole and a plant vacuole (Cell Models, 2006).  In animal cells, the vacuole generally has a small size.  It is used for storing waste products and serves as an area for digestion.  In plant cells, the vacuole makes up a much larger percentage of the internal volume.  Besides the functions of waste storage and digestion, the plant vacuole has other important roles.  Plant vacuoles hold nutrients and water.  They help the plant cells to expand during the cellular growth process.  Perhaps most importantly, the plant cell vacuole maintains turgor pressure within the plant.  They blow up much like a balloon and exert outward pressure within a confined space.  As a result, the plant is able to stand erect.  When the vacuoles become dehydrated the plant will wilt. 

Plant cells have a unique structure called the cell wall which is not present in any animal cell (Biology Online, 2005).  This rigid and fibrous structure contains the contents of the entire plant cell.  It is a protective structure that gives a plant its specific shape.  When the plant vacuole fills with water, it exerts outward pressure on the cell wall and the plant holds its rigidity.  The cell wall is composed of polysaccharides, generally cellulose.  The fiber content of vegetables in the human diet is in direct proportion to the indigestibility of the plant cell wall within the intestines.  The cell wall gives rise to another difference between animal cells and plant cells, plant cells are rectangular and animal cells are round in shape.

All animal cells have a structure called a centriole, but most plant cells do not have a centriole.  The two centrioles of an animal cell group together to form the centrosome.  During cellular replication, the centrosome plays an important role in both animal and plant cells.  Plant centrosomes are not as complex as animal cells, but still, they serve as the microtubule organizing center where the microtubules are made.

            Finally, all plant cells have plastids and no animal cells have these (Diffen, 2009).  Plastids are primary structures that can take on many possible forms.  Chloroplasts are a common product of plastid differentiation and are also unique to plant cells.  These structures are the site of chlorophyll production and storage.  This is the place where photosynthesis occurs, the process where light energy acts to convert carbon dioxide into sugars.  Only plant cells can perform this miracle.