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10.17 Intro to Bacteriology
at 8:00 by Dr. Hobden
77
Microbiology
Professional
10/17/2011

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Cards

Term
What type of ribosomes are in eukaryotes?
Definition
80S
Term
T/F Most bacteria possess peptidoglycan
Definition
true
Term
T/F Prokaryotic mRNA is usually spliced before it can be translated.
Definition
false! prokaryotic mRNA does not need processsing
Term
What are the four steps of the gram stain?
Definition
step 1= crystal violet for 1 min, rinse
step 2= Gram's Iodine for 1 min, rinse
step 3= decolorizer (alcohol or acetone) for 30-60 seconds and rinse
step 4= safranin red
Term
What color are gram positive and gram negative bacteria on a gram stain?
Definition
gram + are blue, gram - are red
Term
What color do acid fast positive bacilli stain?
Definition
stain red (while acid fase - bacteria stain blue)
Term
What are the steps for acid fast staining?
Definition
primary stain (carbolfuchsin red) for 5 minutes then rinse, decolorizer (HCl, alcohol), and then counterstain with methylene blue or malachite green for 1-3 minutes
Term
What are capsules made out of?
Definition
high MW polysaccharide or peptide like N-acetylmuramic acid (NAM) and N-Acetylglucosamine (NAG)
Term
How do capsules help bacteria evade the immune system?
Definition
protect against complement and are anti-phagocytic. Also capsules facilitate adherence of bacteria to surfaces.
Term
How big are bacteria?
Definition
most range in size .25-1 um wide and 1-3 um long
Term
In gram staining, idion acts as a ____ and complexes with crystal violet in the cytoplasm of bacteria.
Definition
mordant
Term
What factors can affect the results of gram staining?
Definition
old cultures of g+ may appear G variable. Antibiotic treated cells can give false gram reactions. Also cell walls with LCFA are difficult to decolorize with acetone/alcohol and appear as poorly stained gram +
Term
T/F All bacteria have cell walls.
Definition
false, ex. mycoplasma doesn't
Term
What determines if a bacteria is acid fast or not?
Definition
presence of LCFA (mycolic acids) in bacterial cell walls make them AF
Term
What are the two methods for acid fast staining?
Definition
hot (Ziehl-Neelsen) or cold (Kinyoun) methods. Cold is more often used today
Term
What do acid fast + bacteria look like on acid fast stain?
Definition
AF+ are red, AF- are blue or green
Term
round bacteria =
Definition
coccus
Term
ovoid bacteria=
Definition
coccobacillus
Term
rod-shaped bacteria =
Definition
bacillus
Term
spindle shaped bacteria =
Definition
fusiform
Term
"seagull" or comma-shaped bacteria=
Definition
curved
Term
Corkscrew shaped bacteria=
Definition
spiral
Term
What are the common cell arrangements of bacteria?
Definition
single, pairs, tetrads, clusters, chains
Term
production of bacterial capsule depends on...
Definition
environmental and growth conditions
Term
What is a glycocalyx?
Definition
a less organized form of a capsule that is a polysaccharide film over the surface of bacterial cells
Term
What is an S-layer?
Definition
slime layer that appears as a matrix of fibers, even less organized than the glycocalyx
Term
What is the outer membrane of a bacteria composed of?
Definition
bilayer of LPS and phospholipids
Term
Which bacteria have outer membranes? why?
Definition
gram negative, they function as an initial barrier to the environment
Term
What are LPS made out of?
Definition
repeating sugar residues attached to core sugars which are then attached to a disaccharide-diphosphate with fatty acid moieties. Repeating sugar residues are useful for bacterial typing (Oantigen), impart a hydrophilic nature ot the bacterial cell
Term
What is the bioactive portion of LPS?
Definition
lipid A= disaccharide diphosphate with fatty acid chains
Term
What are porins?
Definition
proteins scattered throughout the LPS which control the passage of small water soluble nutrients and other molecules like antibiotics, and specialized transport proteins for larger hydrophobic compounds
Term
What is the purpose of the lipoproteins scattered throughout bacterial LPS?
Definition
anchor the outermembrane to the next deeper layer in the cell envelop, the cell wall
Term
What's another name for the peptidoglycan layer?
Definition
murein layer
Term
What is the function of the peptidoglycan layer?
Definition
found in both gram + and gram - bacteria; gives bacteria cell shape and strength to resist osmotic changes in teh environment. Protects against mechanical damage and provides some barrier effect against larger substances
Term
What is the peptidoglycan layer/murein layer composed of?
Definition
disaccharide-pentapeptide subunits which are N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). Crosslinked via peptide bridges between NAM to form sheets of peptidoglycan. Sheets of peptidoglycan are then crosslinked.
Term
What's the different b/t the peptidoglycan layer of G+ and G-?
Definition
in G+, the peptidoglycan layers have teichoic or mycolic acids (acid-fast) to fortify cell walls
Term
What is the periplasmic space?
Definition
in G- bacteria, bounded by the internal surface of the outermembrane and the external surface of the cytoplasmic membrane. Contains thin layer of peptidoglycan.
Term
T/F The cytoplasmic membrane of bacteria generates ATP.
Definition
true
Term
T/F The cell membrane mediates chromosomal seperation during bacterial replication.
Definition
true
Term
What are pili composed of?
Definition
subunits of protein called pilin, which are found in a pool together with assembly machinery in the periplasmic space
Term
What are the two types of pili?
Definition
common and sex
Term
What is the function of common pili?
Definition
fimbriae or type IV pili mediate adhesion to host eukaryotic cells with specialized tipstructures to recognize specific carbs
Term
What are sex pili?
Definition
serve as conduits for passage of DNA from one bacterial cell to another ina process known as conjugation
Term
Rapid extension and retraction of type ___ ili results in a form of locomotion known as _____.
Definition
IV; twitching motility
Term
T/F Pili and flagella are antigenic.
Definition
true
Term
What are flagella?
Definition
long helical filaments composed of a rotary motor (a basal body complex with assoc proteins), a flexible universal joine (the hook), and a rigid propeller (a filament composed of a single protein-flagellin)
Term
What is H antigen?
Definition
the antigen for flagellin (highly antigenic)
Term
What is H antigen?
Definition
the antigen for flagellin (highly antigenic)
Term
What powers the flagella motor?
Definition
protons
Term
What is the purpose of inclusion bodies in bacteria?
Definition
store reserve granules (glycogen and polyphophate are the MC)
Term
What is the nucleoid?
Definition
highly coiled bacterial chromosome intermixed with RNA, polyamines, and support proteins
Term
What are two different types of plasmids?
Definition
resistence and virulence
Term
What are endospores?
Definition
a resting phase of bacteria when living conditions get tough, NOT A REPRODUCTIVE STRUCTURE
Term
Endospores are resistent to...
Definition
desiccation, light, heat, many disinfectants, radation, etc.
Term
How do you kill spores?
Definition
autoclaving, high heat for a period of time and right concentrations of certain disinfectants
Term
What are mesosomes?
Definition
invaginations of the cytoplasmic membrane, involved in septation
Term
How do bacteria bring in nutrients?
Definition
passive and carrier mediated diffusion, active transport, group translocation
Term
What substances do bacteria bring in to the cell via passive and carrier mediated diffusion?
Definition
water, O2, carbon dioxide, and simple sugars enter by virtue of a concentration gradient
Term
What nutrients do bacteria bring in via active transport?
Definition
energy dependent pumps in the cell envelope bring certain sugars, most amino acids, organic acids, and many inorganic ions into the cell
Term
What do bacteria bring into the cell via group translocation?
Definition
similar to active transport but the nutrient being transported gets chemicallymodified before being brought into the cell; many sugars, purines, pyrimidines, and fatty acids are brought in this way
Term
T/F If possible, bacteria would rather use preformed compounds like amino acids, vitamines, nucleotide phosphates, etc. rather than synthesize them de novo.
Definition
true
Term
What are fastidious growers?
Definition
bacteria that have lost the ability to synthesize substances essential to growth and will only thrive in their hosts
Term
What two general mechanisms do bacteria use to generate ATP?
Definition
substrate level phosphorylation and oxidative phosphorylation
Term
How do bacteria cause dental caries?
Definition
oral S. mutans takes in sucrose and rapidly ferments it into acids which then eat into tooth enamel
Term
What does it mean for a bacteria to be microaerophilic?
Definition
can only handle small amounts of oxygen otherwise it will be toxic
Term
Trimethoprim inhibits what bacterial enzyme?
Definition
dihydrofolate reductase
Term
How does trimethoprim specifically inhibit bacterial dihydrofolate reductase and spare human DHFR?
Definition
human enzyme needs 50,000 x bacterial dose for inhibition
Term
Peptidoglycan is synthesized from monomeric units composed of ____ coupled to either NAG or NAMA.
Definition
uridine diphosphate (UDP)
Term
UDP-NAG and UDP-NAMA are polymerized then crosslinked to each other by means of a __ reaction.
Definition
transpeptidation reaction
Term
What's a really complicated name for the glycolytic or anaerobic pathway?
Definition
EMP (Emden-Myerhof-Parnas)
Term
What are the end products of fermentative metabolism?
Definition
acids, alcohols, carbon dioxide, and hydrogen
Term
What are different ways to distinguish between different bacteria?
Definition
staining, selective media, differential media, sequence 16S ribosomal RNA
Term
What are some examples of bacterial aerobes?
Definition
mycobacterium tuberculosis, pseudomonas aeruginosa, and bacillus anthracis
Term
What are some examples of anaerobe bacteria?
Definition
clostridium botulinum, bacteriodes melaningenicus
Term
What are some examples of bacterial facultative aerobes?
Definition
E coli, shigella dysenteriae, s. aureus
Term
What is an example of a bacterial microaerophilic?
Definition
campylobacter jejuni
Term
Who created the first antibiotic and what was it?
Definition
prontosil rubrum (prodrug of sulphanilamide) by Gerhard Domagk
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