Introduction to Bacteria Flashcards
Describe the ways in which bacteria are identified by using particular features of their size, shape, growth requirements and staining characteristics.
o Gram Staining
• Gram positive - violet
• Gram negative - red
o Shape
• Cocci - Spherical
• Bacilli – Rod Shaped
Describe the main structures and functions of a typical bacterial cell
o Penicillin Binding Proteins - enzymes which synthesise peptidoglycans
o Peptidoglycans - give the cell strength and shape. Carbohydrate polymers cross linked with amino acids
o Lipopolysaccharide (LPS, endotoxin) - component of Gram Negative cell wall
o Flagellum - motility
o Fimbriae - adherence
Explain the classification of and nomenclature used for bacterial species.
The name is based on the genus and the species. Strains of a species has similar characteristics. Typing is used to identify strains.
Describe spores
Spores - a minute, typically one-celled, reproductive unit capable of giving rise to a new individual without sexual fusion, characteristic of lower plants, fungi, and protozoans. How they tolerate stress or unfavourable environments
Describe plasmids
Plasmids - a genetic structure in a cell that can replicate independently of the chromosomes, typically a small circular DNA strand in the cytoplasm of a bacterium or protozoan. Plasmids are much used in the laboratory manipulation of genes. Involved in conjugation
How do bacteria replicate?
Binary fission to make identical progeny
How does genetic variation arise in bacteria?
o Spontaneous mutation
o Transfer of DNA
3 processes of DNA transfer
Conjugation - from filus of other bacterial cell
Transformation - from DNA in environment
Transduction - from a bacteriophage
Describe the culture of S. Aureus
Clustered gold round shaped bacteria, usually cultured on blood agar
Where do infections of nosocomialis bacterial species usually originate?
From hospital settings
