Introduction to Bacteria Flashcards Preview

Principles of Disease 16 > Introduction to Bacteria > Flashcards

Flashcards in Introduction to Bacteria Deck (10)
1

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

2

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

3

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.

4

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

5

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

6

How do bacteria replicate?

Binary fission to make identical progeny

7

How does genetic variation arise in bacteria?

o Spontaneous mutation
o Transfer of DNA

8

3 processes of DNA transfer

Conjugation - from filus of other bacterial cell
Transformation - from DNA in environment
Transduction - from a bacteriophage

9

Describe the culture of S. Aureus

Clustered gold round shaped bacteria, usually cultured on blood agar

10

Where do infections of nosocomialis bacterial species usually originate?

From hospital settings