Cell Envelope Flashcards
For most species, the cell envelope includes at least (blank) structural supporting layer
1
What is the most common cell envelope?
the cell wall
Define cell envelope.
cell wall + all other associated layers
What do mollicutes lack?
a cell wall
What is peptidoglycan?
a polymer of 2 sugars and amino acids
What are the 2 sugars in peptidoglycan?
N-acetylglucosamine and N-acetyl-muramic acid
Where are the amino acids attached?
the NAM
What does peptidoglycan form?
a rigid, porous sac (murein nucleus) that surrounds the CM, helps it withstand turgor pressure
What is unique to bacteria?
peptidoglycan
What does penicillin inhibit?
transpeptidase
Why do they inhibit this?
they inhibit enzymes responsible for making peptidoglycan
What does vancomycin prevent?
cross-bridge formation by binding to terminal amino acids
List the things a positive cell wall includes.
nucleoid, ribosomes, cytoplasm, cytoplasmic membrane
How thick is a gram positive cell wall?
20-80um
What are some pros of a cell wall?
strong, protects against osmosis lysis, adds shape
What are some cons of a cell wall?
must be protected from lysozyme
(blank) are classified with positive bacteria.
mycobacteria
What 4 things does a mycobacteria have?
thick peptidoglycan, thick arabinogalactan, myolic acids, capsule of lipids and glycolipids, therefore they are extremely resistant to environmental stress but they must grow slowly
List the things a gram-negative cell includes.
nucleoid, ribosomes, cytoplasm, cytoplasmic membranes
What are some pros about a gram negative cell?
outer membrane is a good selectively permeable membrane, has a built-in storage, protection against osmotic lysis
What are some cons about a gram-negative cell?
toxic, expensive, larger genomes
What is a lipopolysaccharide?
complex glycolipid that are split into 2 groups
What are the 2 types of lipopolysaccharides?
O-antigen and lipid A endotoxin
What is O-antigen used for?
serological typing
