Biology Essay Ap

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1. There are two main types of cells, prokaryotic and eukaryotic. The connection between the two can be seen right from their prefixes, pro meaning before and eu meaning true or good. This is because prokaryotic cells are before a nucleus and eukaryotic cells possess a true nucleus. This has led to many theories that eukaryotic cells have evolved from prokaryotes. The evidence for this is most noticeable in the structure of the cells, which will be compared below.

Prokaryotic cells have no nuclei and contain few organelles as shown below.

Eukaryoitc cells have a nuclei and contain many organelles.

While the two cells might appear very different they do have many things in common and perform most functions in the same ways. Both prokaryotic and eukaryotic cells are enclosed by plasma membranes, filled with cytoplasm, and are filled with small structures called ribosomes. Both also contain DNA, which carries the archived instructions for operating the cell. The similarities go beyond visible things, as physiologically they are also very similar. An example of this is 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. Other things in the two cells that may appear a difference aren’t, an example being prokaryotic cells have a cell wall, and while not all eukaryotic cells have a cell wall, many do including plant cells.

There are also many differences between the two cells, the most obvious being the size of the two and with the difference in complexity. The most distinct difference is that Eukaryotic cells have a true nucleus bound by a double membrane. Prokaryotic cells do not have one. Another difference is despite the fact they both have DNA, eukaryotic DNA is complexed with proteins called histones and is organized into chromosomes. Prokarytoic DNA is naked, meaning it has not histones associated with it, and it is not...
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