Bacterial Physiology Flashcards
(11 cards)
1
Q
Nucleoid
A
- Prokaryote - one chromosome
- No nuclear membrane
- Plasmids - many bacteria have small extra chromosomal pieces of DNA
2
Q
Bacterial cell envelope
A
- Cytoplamsic membrane
- Cell wall
- Capsule / slime layer
- Cell structures
3
Q
Bacterial cell wall
A
- Rigid - gives cell shape
- Protects the cell against attack
- Bacteria divide into 2 groups based on the Gram stain
- Contains Peptidoglycan - consists of 2 chemicals - N-acetyl glucosamine (NAG) and N-acetyl muramic acid (NAM)
4
Q
Structure of peptidoglycan
A
- Chains of alternating NAM and NAG
- NAM from different layers linked
- Linkage made from peptide chains
- Linkages different in Gram positives and negatives
5
Q
Gram positive cells
A
- Appears purple under light microscope after Gram stain
- Thick cell wall
- 2 major components - teichoic acid and peptidoglycan
- Additional carbohydrates and proteins depending on the organism
6
Q
Gram negative cells
A
- Appears pink after the Gram stain
- Cell wall thinner but more complex
- No teichoic acid
- Outer membrane has lipopolysaccharides and assists in pathogenicity e.g, salmonella
7
Q
Capsule/ slime layer
A
- Sugar coat surrounding prokaryote
- Can be either slime layer or capsule - protects against phagocytosis
- Similar to mucus
- If attached to cell = capsule
- If loosely associated = slime layer
8
Q
Fimbraiae
A
- Thin , straight appendages - protein
- Involved in pathogenesis
9
Q
Pili
A
- Specialised fimbriae
- Involved in transfer of genetic material from cell to cell
10
Q
Flagella
A
- Responsible for motility
- Long, thin protein appendages
- May be 1 or many flagella/cell
- May be positioned at ends of cell or all over surface
11
Q
Types of flagella
A
- Peritrichous
- Polar
- Lophotrichous
