The General Structure Of A Virus And A Bacterium Essay

1848 Words Aug 24th, 2016 8 Pages
Question 1A: Compare and contrast the general structure of a virus and a bacterium.
Bacteria and viruses both do not contain a DNA enclosing nucleus; however, these organisms differ greatly in the complexity of their structures. Generally a bacterium is encompassed within a semi-rigid cell wall made of peptidoglycan, which provides structural support. It is classified as gram positive if its cell wall is thick and stains purple when tested for identification. If its cell wall is thin and stains red, it is referred to as gram negative. Under the cell wall, the bacterium also has a plasma membrane made up of a phospholipid bilayer with proteins inserted inside. Within its cytoplasm, ribosomes for protein synthesis and a single DNA strand are contained. Some bacterium also has additional nucleic acid inside a plasmid in the cytoplasm. A sticky slime layer or capsule consisting of polysaccharides called glycocalyx can be found at the cell surface of some bacterium. Further, rigid filaments called flagella and outer cell surface appendages called pili and fimbriae, which are hair-like structures, can be found on others. The classification of a bacterium is dependent on its size, shape (spherical, rod or spiral), colour and by how it is arranged together (staph (bunched), diplo (2) or strep (line)). In contrast a virus typically only consists of a core of nucleic acid (either single or double stranded DNA or RNA) for viral replication and a protein coat (or capsid) of…

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