Microbiology

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BACTERIA

Bacteria are structurally the simplest and most abundant of organisms and because of their chemical effects, toxin-producing properties and role in the spread of disease they tend to be of major importance to us.

They are single celled organisms normally comprised of some basic cell organelles contained within a membrane and then a strong and rigid cell wall that protects the cell particularly the more active parts.

The difference in cell wall structure between bacteria species allows them to be grouped and identified as either Gram positive or Gram negative. Gram-positive bacteria have a fairly thick cell wall and retain a purple colour when using the Gram stain identification technique. Gram-negative bacteria have a thinner cell but have an additional outer wall layer. It is this layer, which imparts greater resistance to preservatives and antimicrobial agents and also makes many Gram negatives ...