Basic Bacteriology: Bacterial Structures and Taxonomy Flashcards
What is the function and chemical composition of peptidoglycan?
Function: Rigid support, protect against osmotic pressure.
Composition: Sugar backbone with peptide side chains cross-linked by transpeptidase
What is the function and chemical composition of the cell wall/cell membrane of gram positive bacteria?
Function: Major surface antigen
Composition: Peptidoglycan for support. Lipoteichoic acid induces TNF and IL-1.
What is the function and chemical composition of the outer membrane of gram negative bacteria?
Function: Site of endotoxin (lipopolysaccharide [LPS]); major surface antigen
Composition: Lipin A induces TNF and IL-1. O polysaccharide is the antigen.
What is the function and chemical composition of the bacterial plasma membrane?
Function: Site of oxidative and transport enzymes
Composition: Phospholipid bilayer
What is the function and chemical composition of bacterial ribosomes?
Function: Protein synthesis
Composition: 50S and 30S subunits
What is the function and chemical composition of bacterial periplasm?
Function: Space between cytoplasmic membrane and outer membrane in gram-negative bacteria.
Composition: Contains hydrolytic enzymes, including beta-lactamases.
What is the function and chemical composition of bacterial capsules?
Function: Protects against phagocytosis
Composition: Polysaccharide (except Bacillus anthracis, which contains D-glutamate).
What is the function and chemical composition of bacterial pilus/fimbria?
Function: Mediate adherence of bacteria to cell surface; sex pilus forms attachment between 2 bacteria during conjugation
Composition: Glycoprotein
What is the function and chemical composition of a bacterial flagellum?
Function: Motility
Composition: Protein
What is the function and chemical composition of bacterial spores?
Function: Resistant to dehydration, heat, and chemicals
Composition: Keratin-like coat, dipicolinic acid, peptidoglycan.
What is the function and chemical composition of bacterial plasmids?
Function: Contains genes for antibitoic resistance, enzymes, and toxins
Composition: DNA
What is the function and chemical composition of bacterial glycocalyx?
Function: Mediate adherence to surfaces, especially foreign surfaces (indwelling catheter)
Composition: Polysaccharide
What cell wall structures are shared between gram-negative and gram-positive organisms?
Flagellum, Pilus, Capsule, Peptidoglycan, and Cytoplasmic Membrane.
(See figure page 120)
What cell wall structures are unique to gram positive organisms?
Lipoteichoic acid
(See figure page 120)
What cell wall structures are unique to gram-negative bacteria?
Endotoxin/LPS
Periplasm
(See figure page 120)