Bacterial structures Flashcards
Flagella functions
Let bacteria swim
How is the direction swimming in influenced
By environment
Controlled by membrane sensing proteins
e.g. chemotaxis
Pili/Fimbriae functions
Attach to surfaces - necessary for pathogenic bacteria to attach to host
What is conjugation
Can transfer plasmid DNA between cells
Glycocalx function
Protect against dehydration
Protect against microphage attack
Protect against viral (bateriophage) attack
Promotes adhesion to inert surfaces
What is a glycocalx
Polymers of sugars surround some bacterial cells
Form capsule/slime layer
What does the bacterial wall consist of
All structures from and including plasma membrane outward to cell envelope
What is the periplasmic space
Space between plasma membrane and outer membrane
What is the function of peptidoglycan
Give bacterial cell wall rigidity
What is peptidoglycan made of
Polysaccharide repeating sugar units linked by beta-1,4 glycosidic bonds
What links polysaccharide chains
Peptide bridges
What separates cytoplasm from cells environment
Thin barrier
Effect of the bacterial phospholipid bilayer
Hydrophobic core - barrier to most water-soluble molecules Protein permeases (membrane transport protein) allow selective transport of small molecules in
How is the cell shape maintained
Cells usually in hypotonic medium
High concentration of compounds in cytoplasm
Turgor pressure maintains shape
What contributes to internal osmolarity in cell
ALL components DNA, RNA in nucleoid Proteins in transcription/translation in cytoplasm Lipids Inorganic ions and small metabolites
