Flashcards in Morphology and Ultrastructure Deck (85)
Average size of a bacterium?
List a few unique cellular features of Bacteria?
Lack of nucleus and other membranes organelles
DS circular DNA
Smaller Ribosomes (70S)
In gram staining, what colors do positive and negative turn?
Purple = Positive
Red = Negative
What two criteria are primarily used for classification?
What do you do in a gram stain?
Smear, Heat fixation, crystal violet + iodine, wash, safranin
What makes a gram + purple?
Stain gets trapped in the thick, cross-linked peptidoglycan layer.
What stain you yo use for mycobacterium?
How (what lab technique) would you use to assess bacterial genetics? When would this be important?
Esp. Important for slow growing strands
The lack of a bacterial nuclear membrane allows for...
Coupled Transcription and Translation
Location of DNA in the bacterial cell?
the nucleoid and plasmids
Size of two subunits and full ribosome complex?
30S + 50S = 70S
With the exception of myco, what do bacterial cell membranes lack?
Three important roles of the bacterial lipid bilayer?
Electron Transport/Energy Production
Pumps present to maintain internal environment
Lined internall with actins that determine shape/division
Describe a G+ cell wall
Teichoic Acids Make covalent linkages and anchor to membrane
What does lysozyme do to fight bacteria?
Cleaves glycan backbone of peptidoglycan
Death by loss of osmotic control
Are peptidoglycan and techoic acid still present in gram negs?
A little PG
What parts of PG binds to provide crosslinkage?
D-Ala to Lys
Two repeating subunits in PG?
NAG and N-Acetylmuranic Acid
Importance of the periplasmic space in gram negatives?
Breakdown molecules (proteases, phosphotases, lipases)
Many lytic virulence factors
Type ___ virulence factors are a major virulence factor
Describe the outer membrane of a gram negative.
Inside normal, outside LPS
LPS is also known as ______. When released it triggers a _______.
What is LPS without its O antigen?
What are the transmembrane proteins called? What gets through them?
Materials under 700 Da
Role of lipoproteins in G- bacteria?
Hold outer membrane onto the bacteria
How is LPS crosslinked?
Mg and Ca linkages between phosphates
What is a bacterial capsule?
A loos polysaccharide or protein layer
Why do we can about bacterial capsules?
Increase Adherance -- Biofilms in quorum
What are flagella?
Ropelike cellular propellers made of heavily coiled flagellin.
Driven by ATP motor and chemotactic signals