Comparing Prokaryotes And Eukaryote Cells

The cell is the basic functioning unit of organisms in which chemical reactions take place. These reactions involve an energy release needed to support life and build structures. The cell consists of membrane bound organelles, which are responsible for the division of labour. There are two main classes of cells- Prokaryotes which are cells without a nucleus, where the DNA is spread around the cytoplasm of the cell, an example of a prokaryote is a bacterium (See Figure 1). The other class is the Eukaryotes which are the cells of plants and animals, and example is a palisade cell (See Figure 2). Both have similarities and differences in their functions and structures.

Both Prokaryote and Eukaryote cells consist of Cell wall, (however this is not present in animal cells) - this is made of Peptidoglycan (though the plant cell is made of cellulose microfibrils embedded in a layer of calcium pectate and hemicelluloses). The cell wall provides support for a plant cell, and
Most notably the lack of a nucleus in prokaryotes and membrane bound organelles. The DNA of prokaryotes floats freely around the cell; the DNA of eukaryotes is held within its nucleus. The organelles of eukaryotes allow them to exhibit much higher levels of intracellular division of labour than is possible in prokaryotic cells. Another physical difference is the size of both cells. A prokaryote is only 0.5-5 μm, whilst Eukaryotes are on average 10 times bigger at up to 40μm. Mitochondria are absent from Prokaryotes, yet found in Eukaryotes, as are chloroplasts (though chloroplasts are not found in animal cells). One difference as far as existence is concerned, is that prokaryotes are believed to be the first form of life around 3.5 billion years ago. Eukaryotes are much younger, and believed to have existed around 1.5 billion years ago when the cells developed a nucleus- multicellular organisms are younger still at 0.5 billion years