BI323 Final Exam Material from Exam 1 Flashcards
Koch’s postulate
used to prove a casual relationship between microorganism and disease
What are the 4 protocols in Koch’s postulate?
1.) microorganisms must be present in every case of disease but absent in healthy individuals
2.) suspected microorganism must be isolated and grown in pure culture
3.) some disease must result when isolated microorganism is inoculated into a healthy host
4.) same microorganism must be isolated again from diseased host
increase in apparent size of specimen that’s calculated by multiplying magnification factors of lenses
magnification
minimum distance that 2 objects can be separated from 1 another and still be recognized as distinct objects
resolution
How can you increase resolution?
1.) focus illumination light
2.) decrease illumination wavelength
3.) oil immersion at 100X
method of lighting specimen from an opposite objective
brightfield illumination
illumination of specimen without projecting light directly into objective with specialized microscopic lighting technique
darkfield illumination
What is the purpose of preparing and visualizing specimen?
1.) increase visability
2.) accentuates specific morphology features
3.) preserves specimen
What is the process of preparing a specimen for staining and visualization?
1.) fixation
2.) staining
3.) visualization
preserves overall morphology but not internal structures
heat fixation
protects fine cellular substructures and morphology of larger, delicate organisms
chemical fixation
use of a single agent/dye with more frequently basic dyes being used (crystal violet, methylene blue)
simple staining
divides microorganisms into groups based on staining properties
differential staining
based on cell wall composition
-Gm+ bacteria have a thick peptidoglycan layer that prevents loss of crystal violet
-Gm- bacteria have a thin peptidoglycan layer, not preventing decolorization
Gram staining
Briefly describe the gram staining process.
1.) crystal violet is the primary stain
2.) Gram iodine as the mordant
3.) 95% ethanol as the decolorization
4.) safranin as the counterstain
What would the results of gram staining mean?
Gm+ = purple
Gm- = pink
stained Myobacterium (tuberculosis and leprosy) based on high lipid content in cell walls
acid-fast staining
visualize capsules that appear colorless against a staining background
capsule staining
double staining technique to visualize a bacterial endospore-green vs. vegetative cell-pink
endospore staining
non-fixed living cells seen through the conversion of phase shifts in light passing through a specimen to brightness changes in image
phase-contrast light microscopy
uses a beam of electrons as a source of illumination
electron microscopy
What is the difference between scanning and transmission when using an electron microscope?
scanning only allows you to see the surface of the organisms vs. transmission allows you to see the internal cellular structures
simpler than eukaryotic cell structure with unique structures not observed in eukaryotes
prokaryotes
sphere-shaped
coccus
pair of sphere-shaped bacteria
diplocuccus
chains of sphere-shaped cells
streptococci
grape-like clusters of sphere-shaped cells
staphylococci
4 cocci in a square
tetrads
cubic formation of 8 cocci
sarcinae
rod shaped bacteria
bacillus
very short rods
coccobacilli
“comma” shaped bacteria
vibrio
rigid helices
spirilum
flexible helices
spriochetes
form hyphae
filementous
branched hyphae
mycelium
includes plasma membrane and surrounding layers
cell envelope
separates cell interior from environment, selectively permeable (transport system), perform crucial metabolic processes, and has TM protein membrane receptor used for detection and response to chemicals
plasma membrane
What are the components of a cell’s plasma membrane?
phospholipids and peripheral and integral membrane proteins
List some macronutrients found in the plasma membrane.
carbon, oxygen, hydrogen, sulfur, nitrogen, phosphorus, potassium, calcium, magnesium, and iron
List some micronutrients found in the plasma membrane.
manganese, zinc, cobalt, nickel, molybdenum, copper
What are growth factors and give some examples?
essential cell components that can’t be synthesized - amino acids, purines, pyrimidines, and vitamins
does not require energy to move substances from a higher concentration to a lower concentration
passive diffusion
spontaneous transport of glycerol, amino acids, and sugars from a higher concentration to a lower concentration with the size of the gradient impacting uptake rate
-rate reaches a plateau
-has a presence of carrier molecules and requirement of smaller concentration gradient
facilitated diffusion
energy-dependent process whether it is ATP or proton motive force that goes against the concentration gradient and requires carrier proteins
active transport
transports sugars, amino acids, and specific antibiotics
-ubiquitously conserved
-consists of 2 nucleotide binding domains and a substrate binding protein that delivers molecule to transporter
ABC transporteres
use ion gradient to co-transport substances
secondary active transport
2 substances move in the same direction
symport
2 substances move in opposite directions
antiport
energy-dependent process where a molecule crossing the cell membrane gets transported AND transformed in many facultative anaerobes
group translocation
iron sources are transported into Gm- bacterial cell via ABC or enters directly
-siderophores aid in uptake
iron uptake
rigid structure surrounding the plasma membrane giving the cell its shape, provide protection from toxic substances, and contribute to pathogenicity
-made of peptidoglycans
cell wall
hypotonic solutions that the cell wall can protect against
osmotic lysis
hypertonic solutions that cell wall can’t protect against
plasmolysis
What is the cell wall structure of Gm- bacteria?
thin peptidoglycan layer that can easily be decolorized
-outer membrane consists of lipids, lipoproteins, lipopolysaccharides, and adhesion sites
What is the cell wall structure of Gm+ bacteria?
thick peptidoglycan layer that cannot easily be decolorized and contains teichoic acid and a surface layer of proteins
direct contact between plasma membrane and outer membrane that may allow direct movement of material into cell
-found in Gm- bacteria
adhesion sites
What are the 3 components of lipopolysaccarides
O antigen, core polysaccharide, and lipid A
immunogenic and provides protection from host defenses
O antigen
contributes to negative charge on cell’s surface
core polysaccaride
stabilizes outer membrane and is endotoxin
lipid A
space between inner and outer membrane containing periplasmic enzymes and exoenzymes
periplasmic space
function for nutrient acquisition, electron transport, peptidoglycan synthesis, and modification in Gm- bacteria
periplasmic enzyme
function for nutrient acquisition, electron transport, peptidoglycan synthesis, and modification in Gm+ bacteria
exoenzyme
layer of polysaccharides outside the cell wall that are well organized and resist phagocytosis
capsule layer
layer of polysaccharides outside the cell wall that are disorganized, easily removed, and diffuse
slime layer
What is the name for the combination of the capsule and slime layer?
glycocalyx
structured layer of proteins or glycoproteins outside the cell wall that is common among Archaea
s-layer
What is different about Archaeal plasma membrane and cell wall compared to prokaryotes?
-plasma membrane: composed of unique lipids in a monolayer structure
-cell wall: lack peptidoglycans
~70% water between membrane and nucleoid packed with ribosomes and inclusion bodies
cytoplasmic matrix
widely observed in bacteria and archaea functioning in cell divison
FtsZ
found in most rod-shaped bacteria functioning to determine cell shape, chromosome segregation, localizing proteins, motility, and establishing cell polarity
Mbl
observed in C. crescentus inducing curvature
crescentin
found in many photosynthetic and high respiratory activity bacteria acting as an aggregate of spherical and flattened vesicles and tubular membrane
plasma membrane in-foldings
membrane-bound organelle unique to Planctomycetes that generates and maintains a proton motor force for ATP synthesis
anammoxosome
aggregation of (in)organic materials
inclusions
What are the 2 carbon storage inclusions?
glycogen and poly-B-hydroxybutyrate (PHB)
What does a phosphate inclusion store?
polyphosphate granules
What does a sulfur inclusion store?
sulfur globules
What does a nitrogen inclusion store and in which bacteria?
cyanophycin granules in cyanobacteria
not bound by lipid bilayer that functions as other than metabolic stockpile
-EX: carboxysomes
microcompartments
have hollow cylindrical vesicles to help with buoyancy in some aquatic prokaryotes
gas vacuoles
found in aquatic bacteria containing iron, orienting cells in magnetic fields
magnetosomes
complexes of protein and RNA that function in protein synthesis
ribosomes
What are the ribosomal subunits that make up 50S?
protein, 5S, and 23S
What are the ribosomal subunits that make up 30S?
protein and 16S
~ 60% DNA, 30% RNA, and 10% protein located in 1 circular chromosome that is not membrane-bound
-some may have more than 1 chromosome and it may be linear
nucleoid
small, closed circular DNA molecules that have selective advantages and are extrachromosomal
-laterally transferred and used for molecular biological applications
plasmids
short, thin, hairlike, proteinaceous appendages attached to cell’s surface with up to 1,000 per cell
fimbria
What does it mean when a fimbria is polar?
located at 1 end
What does it mean when a fimbria is monotrichous?
1 flagellum
What does it mean when a fimbria is amphitrichous?
1 flagellum at each end
What does it mean when a fimbria is lophotrichous?
cluster of flagellum at 1 or both ends
What does it mean when a fimbria is peritrichous?
flagellum are spread over the entire cell surface
hollow rigid cylinder found in the flagellum
filament
links filament to basal body in the flagellum
hook
series of rings driving flagellar motor
basal body
What does it mean when the flagellum is moving in a counterclockwise motion?
forward motion/run
What does it mean when the flagellum is moving in a clockwise motion?
disrupts run/tumble
flexing/spinning movement driven by periplasmic axial fibrils
spirochete motility
type IV pili that’s jery and irregular motions
twitching motility
coasting along solid surfaces with no known visible motility structure
gliding motility
What is different about the archaeal flagella?
it has 1+ flagellin subunit type with no hollow filament and rotational movements
similar to fimbrae but is required for mating, is longer, thicker, and less numerous with only 1-10 per cell
sex pili
movement towards or away from a chemical that’s detected by cell surface chemoreceptors
chemotaxis
What happens when there is an absence of chemochemoattractant?
there are random movements
What happens when there is a chemoattractant?
there are directional movements
dormant and resist numerous environmental conditions-heat, radiation, chemicals, and desiccation
-have a thick spore coat that is impermeable peptidoglycan cortex and core wall surrounding the nucleoid and ribosomes
endospores
Why is believed that endospores are resistant to many environmental conditions?
it has a dehydrated core, spore coat, and DNA repair enzymes
formation of spores when there is a lack of nutrients
sporulation
What are the general 3 steps of sporulation?
1.) activation prepares spores for germination
2.) germination causes rupture and absorption of spore coat caused by spore swelling
3.) outgrowth causes emergence of vegetative cell
