3 Flashcards
What is the typical thickness of the peptidoglycan layer in Gram negative cells?
2-7 nm
What protein links the outer membrane to the peptidoglycan layer in Gram negative bacteria?
Braun’s lipoprotein
What are the two leaflets of the outer membrane in Gram negative bacteria?
Inner leaflet and outer leaflet
What composes the inner leaflet of the outer membrane in Gram negative bacteria?
Phospholipids
What are the three parts of lipopolysaccharides (LPS)?
- Lipid A
- Core polysaccharide
- O side chain
What is the function of the O side chain in lipopolysaccharides?
Serves as the antigen site on the gram negative bacterium’s outer membrane
True or False: The lipid A portion of LPS can act as a toxin.
True
What is the process of transport into a Gram negative cell?
A 2 step process: * Solutes cross the outer membrane; * Integral membrane proteins perform the transport.
What happens to bacteria in hypotonic solutions without peptidoglycan?
They would burst (lysis)
What is the result of bacterial cells treated with lysozyme or penicillin in a hypotonic solution?
They will lyse
What type of bacteria lack a cell wall?
Mycoplasma and a few other genera
What are extracellular vesicles (Evs) in Gram positive cells composed of?
A small amount of cytoplasm surrounded by plasma membrane
What are the layers outside the cell wall called?
- Capsules
- Slime layers
- S-Layers
What is the composition of the protein capsule of Bacillus anthracis?
Poly-D-glutamic acid
What role do capsules play in bacterial survival?
Help cells resist phagocytosis
What is the protoplast in bacterial cells?
The plasma membrane and all of its contents
What do polyphosphate granules store?
Phosphate needed for making important cell constituents like nucleic acids and ATP
What is the function of carboxysomes?
Contain important enzymes for carbon fixation
What is the Svedburg unit associated with bacterial ribosomes?
70S ribosomes, containing a 50S and a 30S subunit
What is the typical chromosome structure in most bacteria?
A circle of double stranded DNA
True or False: Most bacteria carry more than one copy of their chromosome.
False
What is the typical length of bacterial chromosomes in base pairs?
0.5 – 10 million base pairs
What is the term for bacteria that lack a cell wall?
Pleiomorphic
What is the primary function of slime layers in bacteria?
Facilitate motility
