BRAINCAKEBacterial Toxins
Pathogenic bacteria cause disease in two main ways: by invading and damaging host tissues, and by producing toxins. A toxin is a poisonous substance that damages host cells or disrupts the way the body works. Many of the symptoms of bacterial disease, such as fever, diarrhoea and vomiting, are caused by toxins rather than by the bacteria themselves.
Bacterial toxins fall into two groups.
Endotoxins are lipopolysaccharides (lipid joined to carbohydrate) that form part of the outer layer of the cell wall of Gram-negative bacteria. They are released mainly when the bacteria die and break open. Salmonella is an example.
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
Key terms in this lesson
- gram-negative
- Describes bacteria with a thin peptidoglycan wall and an outer membrane that does not retain crystal violet, appearing pink in Gram staining.
- gram-positive
- Describes bacteria with a thick peptidoglycan cell wall that retains crystal violet stain and appears purple in Gram staining.
More in Bacteria and Disease
- Area and Mass of Fungi
- Growth of Bacterial Colonies
- Logarithmic Scale
- Exponential Growth
- Endotoxins
- Salmonella spp.
- Exotoxins
- Staphylococcus spp.
All 30 lessons in Bacteria and Disease · All Edexcel A-level Biology topics