Prokaryotic and Eukaryotic Cell Structure

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. There are two general categories of cells: prokaryotes and eukaryotes.The one that I choose to discus is eukaryotes cell.

Eukaryotes include fungi, animals, and plants as well as some unicellular organisms. Eukaryotic cells are about 10 times the size of a prokaryote and can be as much as 1000 times greater in volume. The eukaryotic cell consists of numerous parts each performing a function. The eukaryotic cell consists of a nucleus, which is the centre of the cell; within the nucleus is what is known as nucleolus which is a knot of chromatin. Chromatin is the portion of the nucleus that contains all the DNA of the nucleus in animal or plant cells. Then there is mitochondria which are the energy source for the cell. Then we have ribosomes which construct the protein in the cell building chains of amino acids one amino acid at a time. Last but not least we have the endoplasmic reticulum which is responsible for the production of protein and lipids of most of the cell's organelles. The endoplasmic reticulum creates a network of membranes throughout the whole cell.

The nucleotide area of a prokaryotic cell is both similar to a nucleus in a eukaryotic cell and different. The similarities are that they are both performing most of the same kinds of functions, and in the same ways. Both are enclosed by plasma membranes, filled with cytoplasm, and loaded with small structures called ribosome. Both have DNA which carries the archived instructions for operating the cell. And the similarities go far beyond the visible--physiologically they are very similar in many ways. For example, the DNA in the two cell types is precisely the same kind of DNA, and the genetic code for a prokaryotic cell is exactly the same genetic code used in eukaryotic cells. The differences are that the Eukaryotic cells have a true nucleus, bound by a double membrane. Prokaryotic cells have no nucleus. The purpose of the nucleus is to sequester the DNA-related functions of the big eukaryotic cell into a smaller chamber, for the purpose of increased efficiency. This function is unnecessary for the prokaryotic cell, because it's much smaller size means that all materials within the cell are relatively close together. What is more eukaryotic DNA is linear; prokaryotic DNA is circular. Also Eukaryotic DNA is complexes with proteins called "pistons," and is organized into chromosomes; prokaryotic DNA is "naked," meaning that it has no pistons associated with it, and it is not formed into chromosomes. Though many are sloppy about it, the term "chromosome" does not technically apply to anything in a prokaryotic cell. A eukaryotic cell contains a number of chromosomes; a prokaryotic cell contains only one circular DNA molecule and a varied

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