Bacteria and parasites

Bacteria and parasites - What are the parts of the cell...

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Bacteria and parasites This note coves bacteria and parasites. What are bacteria What are Bacteria? These are single-celled organisms which are characterised by these features: Small (1-10 μm, cf 10 - 100 μm for eukaryotes) The cell is enclosed by a rigid cell wall No membrane about their DNA (“nucleoid”) Most of the cell’s DNA is in a single circular molecule, but there may be additional much smaller circular DNA molecules present termed plasmids They do not have membrane-bound compartments (e.g. Mitochondria) Some have flagella which differ from cilia of eukaryotes Some have polysaccharide “capsule” Some have short fibres projecting from the cell surface - pili (s: pilum) or fimbriae (s: fimbria)
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Unformatted text preview: What are the parts of the cell for? Cell wall: protective & to prevent cell lysing at low osmolality; Membrane: semi-permeable barrier; Nucleoide: where the main cell DNA is; Plasmid: optional extra DNA; Flagella: motility; Capsule: to protect the cell e.g. From antibodies; Pili: join cells to surfaces and to other cells and allow transmission of DNA especially plasmids from cell to cell; Fimbriae: attach cells to surfaces (e.g. Bladder epithelium, the kitchen sink) so that they are not washed away....
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Bacteria and parasites - What are the parts of the cell...

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