Structures, Staining, And Taxonomy Flashcards
What are appendages
Things that are attached to the outside of the cell
What are the types of appendages
Flagella, fimbriae, pili
What is the surface and cell wall layers in a bacteria from the outside in
Capsule
Cell wall
Cell membrane
What is in the cytoplasm in a bacteria
Chromosomes, plasmids, ribosomes, inclusions
What do flagella look like
Long slender, whip like structures, made of protein
Can be single (monotrichous) or multiple in tufts around the cell (peritichous)
What is the purpose of flagella
Enable bacteria to move by roasting like a propeller
How is flagella observed
Can’t be seen with gram stain, only with special stains or electron microscopy
What do fimbriae look like
Shorter, thinner filaments made of protein
What is the purpose of fimbriae
Enable bacteria to attach to substances
What do pili look like
Similar to fimbriae in structure
What is the purpose of Phili
Involve them in the transfer of DNA between bacteria
What is a capsule
Material that is secreted by bacteria and covers the exterior of the cell
Often made of polysaccharide/sugar, may be a thick layer; slime coating
What does a bacterial cell wall look like
Differs from animal cells or fungi
It is a strong layer made of peptidoglycan
What is the purpose of a cell wall in bacterial cells
It maintains cell shape and integrity
It is the principal target for antibiotic action
How are cell walls in bacterial cells viewed
Using gram stains
Differs between gram pos and neg
Why is the bacterial capsule considered a virulence factor
The bacterial capsule is also considered a virulence factor as it enhances the ability of bacteria to cause disease by preventing phagocytosis.
What is the peptidoglycan layer composed of
NAG and NAM (sugars) that are cross linked with amino acids (proteins) that make a long network the covers the cell and protects it from the environment
Composition of gram positive
Thick peptidoglycan layer
No outer membrane
Composition of gram negative
Outer membrane
Then peptidoglycan layer
Space between membranes is the periplasmic space
Is there a nucleus in a bacterial cell
No, there is no nucleus in a prokaryotic cell
What are acid fast bacteria
They have extra waxy lipids in the outside layer that prevent it from being stained using gram staining
What is wet prep
It is used for unstained organisms to be seen
A wet prep is suspended under a cover slip
What are simple stains
Stain is applied and colours the organism
E.g. methylene blue
Does differentiate organisms from one another just its shape, can’t tell if its gram pos or neg because there is no difference in colour