Module 3 pt. 4 Flashcards
The Danish bacteriologist who devised the most frequently used differential stain
Hans Christian Gram
Gram stain
Primary stain
Mordant
Decolorizer
Counterstain
Crystal violet - primary stain
Iodine - mordant
95% ethanol - decolorizer
Safranin - counterstain
Used to fix bacteria sample to formation of a complex of crystal violet and KI
Mordant
Stain does not come out of which type of bacteria?
Gram positive bacteria
Kind of bacteria without cell wall
They have sterols in their cell membranes for stability
Mycoplasma species
Parts of a glycocalyx:
Less discrete structure or matrix which embeds the cell ; diffuse and irregular.ONLY called this when glycocalyx is LOOSELY BOUND
Discrete detectable layer of polysaccharides deposited outside the cell wall; distinct and gelatinous. ONLY called this when glycocalyx is TIGHTLY BOUND. Sharply defined, organized structure
Slime layer
Capsule
Capsules are ___, this contribute to VIRULENCE
Protects against ___
Help adhere to different surfaces like medical implants
Helps trap nutrients near the cell
Soil bacteria protected from dessication
Reserves for carbohydrates
Protect from engulfment
Antiphagocytic
LYSOZYME
Functions of Glycocalyx (5)
Disease - virulence
Protections - Protects from antibiotics, chemicals, white blood cells
Adherance to surfaces - attach to surface of the host
Avoidance of dessication - prevent dryness
In cell-cell recognition - receptors to bind to other cells of close species
The bacteria that uses its slime layer to accumulate on tooth enamel.
Streptococcus (Gram positive)
A polysaccharide-encased mass of bacteria coating a surface
BIOFILM
A common form of protein found in flagella
flagellin
Responsible for the motility of bacteria
Spins like a propeller
Termed the ‘H’ antigen.
Sometimes attach by immune responses
10 - 20 micrometers in length
Flagella
Rotation and rate of flagella
1500 rpm
rate 10 body lengths/second
A flagella is found in all motile bacteria except ___.
Spirochetes
Type of bacteria to have multiple flagella
Helicobacter pylori
Basic parts of a flagella (3)
Twisted but with hollow core
Wide region at the base which connects the two parts
Anchored in cell membrane and cell wall; rings and rod
Filament(flagellin)
Hook
Basal Body (motor)
Rings of a flagella
L
P
S
M
Types of flagellar arrangement (5)
Single flagellum at one pole
Tuft of flagella at one pole
Flagella at both poles
Flagella all over
Tuft of flagella at both ends
Monotrichous
Lophotrichous
Amphitrichous
Peritrichous
Amphilophotrichous
Other kinds of motility (5)
Swarming
Swimming
Twitching
Gliding
Sliding
Different taxis of flagella (4) - seeking out favorable environments or avoiding bad ones
Sense chemicals and move towards regions w/ more nutrients (attractant) and away from regions with toxic materials (repellant)
Swim to regions that contain favorable concentrations of dissolved oxygen
Movement to regions of optimal light intensity and quality
Response to earth’s magnetic field
Chemotaxis
Aerotaxis
Phototaxis
Magnetotaxis
Flagella are ___ helices and bundle and rotate together only when rotating ___.
When they reverse direction going clockwise, instead of a run, flagella unwind and the cell starts a ___ where you would observe a cell seemingly thrashing about in place, causing it to reorient.
Left-handed
counterclockwise
tumble
Detection of motility and presence of flagella (6)
Direct observation by hanging drop method
Dark field microscopy
Motility media
Flagellar staining
Electron microscopy
Immunological detection of “H” antigen
Tiny Hollow projections not involved in movement. Shorter, thinner, and straighter than flagella.
Made up of ___ proteins.
Pili
Pilin
Types of pili (2)
with adhesins
Longer than attachment pili
DNA transfer from one cell to another
Attachment pili (fimbriae)
Conjugation Pili/ sex pili / F pili
