Gram Pos and Neg Flashcards
Capsule
- _______ surrounding bacterial cells
- Consists of ______ made of single or multiple types of sugar residues
- Function of capsule
- Viscous gel
- Polysaccharide
- Protecting bacteria from immune system by evading phagocytosis and interfering with complement deposition
Bacterial cell wall is made of what compound?
Peptidoglycan
Bacterial plasma membranes are exceptionally _______ rich
Protein
What is the function of the bacterial plasma membrane
- Permeability and transport of solutes
- Contains proteins of ETC
- contains receptors for chemotaxis
- Site of DNA synthesis
What are the functions of the cell wall?
- Protection from mechanical disruption and turgor pressure
- Protects from toxic agents
- Permits exchange of nutrients required for growth
Describe the structure of the cell wall.
Gram Positive Bacteria
- Have a lot of ____ in cell wall
- Presence of ____ & _____
- Only ______ cell membrane
- What compound do they lack on their exterior?
- Peptidoglycan
- Teichoic & Lipoteichoic acid
- Single
- LipoPolySaccharide (LPS)
What is the function of teichoic and lipoteichoic acid in cell wall?
They anchor the cell wall to the plasma membrane
Gram Negative Bacteria
- Thickness of peptidoglycan cell wall?
- Structure of membrane compared to cell wall?
- What does the gram negative outer membrane contain?
- What is the function of the outer membrane?
- Thin (single sheet)
- Inner membrane –> cell wall –> outer membrane
- LPS
- Creates a negative charge due to LPS, which makes it harder for the host immune system to attack the bacteria. Also creates a periplasm that holds important enzymes in.
Describe how gram + and gram - bacteria appear when stained and why.
Bacteriostatic
Inhibits growth of bacteria but does not kill
Bactericidal
Inhibits growth and kills bacteria
What is the most common method of inhibition of bacterial growth?
Inhibition of cell wall synthesis and bacterial protein synthesis
Pili
- Made from what protein?
- 2 common types?
- Core of pilus?
- Pilin
- Adhesion and sex pili
- Hollow
What is flagellin?
A protein subunit that anchors flagella to bacterial cell. Each speices only has a single type and the primary protein structure differes between bacteria. They are highly antigenic.
What are spores? What are all medically important spore formers?
- Small dehydrated metabollically quiescent bacteria that are coated by a keratin like insoluble protein coat. They are heat resistant, pH resistant, and can live for a long time. They become inactive when nutritional conditions are unfavorable or depleted. They can reactive when nutrition is more available.
- Gram + rods