The capsule enables the cell to attach to surfaces in its environment. The cell wall acts as an extra layer of protection, helps the cell maintain its shape, and prevents dehydration. Unlike Archaea and eukaryotes, bacteria have a cell wall made of peptidoglycan, comprised of sugars and amino acids, and many have a polysaccharide (carbohydrate) capsule ( Figure 1). Figure 1 This figure shows the generalized structure of a prokaryotic cell. Prokaryotic DNA is found in the central part of the cell: a darkened region called the nucleoid ( Figure 1). We will shortly come to see that this is significantly different in eukaryotes. A prokaryotic cell is a simple, single-celled (unicellular) organism that lacks a nucleus, or any other membrane-bound organelle. Prokaryotes differ from eukaryotic cells in several important ways. Animal cells, plant cells, fungi, and protists are eukaryotes ( eu– = true).Īll cells share four common components: 1) a plasma membrane, an outer covering that separates the cell’s interior from its surrounding environment 2) cytoplasm, consisting of a gel-like region within the cell in which other cellular components are found 3) DNA, the genetic material of the cell and 4) ribosomes, particles that synthesize proteins. The predominantly single-celled organisms of the domains Bacteria and Archaea are classified as prokaryotes ( pro– = before – karyon– = nucleus). Comparing Prokaryotic and Eukaryotic CellsĬells fall into one of two broad categories: prokaryotic and eukaryotic.
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