Prokaryotic cell structure Flashcards
what’s included in the prokaryotic cell structure?
Ribosomes
(Cilium)
Cell membrane
DNA (nucleoid)
Cytoplasm
describe the plasma membrane
Proteins embedded in 2D fluid
Lipids provide the scaffold, proteins provide functions
which are the pre dominant lipids?
Saccarolipids: Lipid A
Glycerophospholipids: PE, PG, CL
Glycerolipid: DGDG
what kind of membrane transport are there?
Passive transport: Facilitated diffusion
Active transporters: energised by ATP or proton motive force (uni, sym, anti)
Group translocation
there are two types of cell walls - describe these
Gram + : thick cell wall (peptidoglycan), thin plasma membrane (1 membrane, thick cell wall)
Gram - : plasma membrane, thin cell wall (peptidoglycan), outer membrane (2 membranes, thin cell wall)
what does peptidoglycan consist of?
2 sugars (glycan) + peptides (4 or 5)
describe the peptidoglycan in gram + bacteria
forms tightly interconnected meshwork, 3D structure
describe the peptidoglycan in gram - bacteria
2D structure, cross links, fewer connections
Outer membrane is made of LPS (lipopoly saccharide), proteins formed by beta sheets
Inner membrane proteins formed by alfa helix
describe teichoic acids
only in gram +, modifies surface charge, provide flexibility, can determine cell shape
describe the gram - flagella
energised through proton gradient across the inner membrane
describe the gram + flagella
same overall structure as gram -. Supporting structures crossing the peptidoglycan and outer membrane are not required
what is a fimbriae (pili)?
smaller, thinner & simpler than flagella, often involved in cell attachment.
Bacterial conjugation: bacterial pili involved in the transfer of genetic material between bacterial cells.
what kind of lipid proteins are most common?
glycerophospholipids: PE, PG, CL
outer membrane proteins are formed by ..?
beta sheets
inner membrane proteins are formed by …?
alfa helixes
what are the two types of bacterial DNA?
chromosomal DNA & plasmid DNA
What are inclusions?
energy & carbon storage
How do bacteria fit their
genome into the cell?
supercoiling
what is the periplasm?
aqueous space between inner & outer membrane (high protein)
what’s an s-layer?
cell surrounding layer, proteins
what’s a capsule?
surrounding layer, proteins/polysaccharides, important for biofilm formation
what’s a hami?
only in archeae. mostly used for attachments –> surface / cell-cell. common in biofilms
what’s the archaeal flagella driven by?
ATP hydrolysis
