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97 Cards in this Set

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Are prokaryotic cells capable of protein glycosylation?
YES
But this process is more rare than it is in eukaryotes.
Are prokaryotes capable of protein secretion?
YES.
They secrete proteins directly across the cell membrane (whereas eukaryotes secrete proteins from the ER)
Are prokaryotes capable of endocytosis, exocytosis, or pinocytosis?
NO!
These are unique capabilities seen in eukaryotes.
What is different about RNA in prokaryotic cells?
It does not contain a polyA tail
Do prokaryotic cells have proteins and ribosomes?
YES.
But their ribosomes have a different structure than eukaryotic ribosomes (making them a good target for antibiotics)
Name 2 unique macromolecules seen in prokaryotes.
1. Lipopolysaccharides (gram (-) only)
2. Peptidoglycan
The eukaryotic flagella demonstrates a "whipping" movement, while the prokaryotic flagella demonstrates a ________ movement.
Rotating
What type of bacteria (gram + or -) have a single cell membrane and a thick peptidoglycan layer?
Gram +
What type of bacteria (gram + or -) stain dark purple when crystal violet stain is added?
Gram +
What type of bacteria (gram + or -) have a thin peptidoglycan layer enclosed within a dual membrane system?
Gram -
What kind of bacteria (gram + or -) do not retain the crystal violet dye, but will appear red-pink when safranin is added?
Gram -
What group of bacteria can be diptheroid, club-shaped?
Gram +
What kind of bacteria can be rod or bacillus-shaped?
Gram + AND Gram -
What group of bacteria can have cocci in "grape-like" clusters?
Gram +
What group of bacteria can have cocci in chains?
Gram +
What group of bacteria can have cocci with a kidney bean shape?
Gram -
What group of bacteria can be vibroid or curved-shaped?
Gram -
What group of bacteria can be spiral-shaped?
Gram -
What kind of bacteria are too small to see by light microscopy and do NOT Gram stain?
L-form
(ureaplasma and mycoplasma)
What kind of bacteria lack a peptidoglycan and therefore are not susceptible to antibiotics that attack the peptidoglycan?
L-form
(ureaplasma and mycoplasma)
What kind of appearance do colonies of L-form bacteria have?
"fried egg" appearance
Is bacterial DNA diploid or haploid?
HAPLOID
In bacteria, where does active transport of nutrients and synthesis of cell envelope layers (peptidoglycan, outermembrane) and capsule occur?
Cell (cytoplasmic) membrane
In bacteria, where does electron transport and oxidative phosphorylation occur?
Cell (cytoplasmic) membrane
How can lysoymes (from tears, for instance) destroy the peptidoglycan structure?
By cleaving the glycosidic linkage between the repeating disaccharide units.
(N-actylglucosamine ---o---- N-acetyl-muramic acid)
What bacterial enzyme is inhibited by B-lactam-type antibiotics?
Transpeptidase
(Responsible for the DAP--D-Ala linkages in the synthesis of peptidoglycan)
What kind of cross-link exists between the DAP and D-Ala residues in the peptidoglycan structure of Gram (+) bacterial?
Pentaglycine crosslink
(makes space for nutrient diffusion)
Which group of bacteria has a very thin peptidoglycan layer (1 or 2 polymers thick)?
Gram (-)
If a bacteria is penicillin-resistant, what enzyme does it have and where is this enzyme located?
Penicillinase (B-lactamase)
Resides in the peptidoglycan in the periplasmic space
Teichoic acids and lipoteichoic acids are polymers of polysaccharides that are only found in...?
Gram (+)
What are techoic and lipoteichoic acids linked to in Gram (+) bacteria?
They are covalently linked to the peptidoglycan
What 2 components of Gram (+) bacteria are responsible for regulation of cell wall autolysins and occasionally serve as receptors for phage?
Teichoic and lipotheichoic acids
What cellular component serves as the group antigen of Streptococci?
Teichoic acids
T or F.

Capsules are always present in gram (+) and gram (-) bacteria.
FALSE.
Capsules can be present in both, but they are not always present.
What is the bacterial capsule mostly composed of?
Polysaccharides
What cellular structure has a protective, antiphagocytic function?
Capsule
What kind of antibiotics should be used against L-form bacteria?
Antibiotics that inhibit protein synthesis
(can NOT use inhibitors of cell-synthesis since L-forms have no peptidoglycan)
From inside --> outside, list the membrane layers of Gram (+) bacteria.
1. Cell (cytoplasmic) membrane.
2. Peptidoglycan
3. Capsule
From inside --> outside, list the membrane layers of Gram (-) bacteria.
1. Cell (cytoplasmic) membrane
2. Periplasmic space
3. Peptidoglycan
4. Outer membrane
5. Capsule
Where are aquaporins located in gram (-) bacteria?
In the outer membrane
Where are periplasmic binding proteins located?
In the periplasmic space
(gram (-) bacteria)
In which layer are lipopolysaccharides found?
Outer (periplasmic) membrane
(gram (-) bacteria)
Gram(-) bacteria secrete various proteins and other molecules into this space to aid in nutrient acquisition.
Periplasmic space
Penicillin resistant bacteria secrete the penicillinase into the _________ where it degrades penicillin.
Periplasmic space
(peptidoglycan layer is present within the periplasmic space)
T or F.

Gram (-) bacteria are innately resistant to penicillins since they have an outer membrane to protect their peptidoglycan layer.
FALSE.

Initially, they were innately resistant to the original antibiotics. But other antibiotics were made to resemble molecules that can travel through the aquaporins of the outer membrane to reach the peptidoglycan in the periplasmic space)
What is the toxic portion of the lipopolysaccharides?
Lipid A
(located at the nonreducing end)
Name the 3 general parts of LPSs?
1. O antigen (highly variable)
2. Core (non-variable)
3. Lipid A (very toxic)
Which part of the lipopolysaccharide can bacteria vary in order to trick our immune systems?
O-antigen
(reducing end)
Which part of the LPS contains KDO?
Core (non-variable region)
The lipid A portion of LPS in gram (-) bacteria can cause what very serious consequence?
ENDOTOXIC SHOCK!
(LPS is a pyrogen--> leads to DIC, vasodilation --> peripheral tissue death and multiple organ failure)
Can flagella be found on both gram (+) and gram (-) bacteria?
YES
Can pili be found on both gram (-) and gram (+) bacteria?
YES.

*However, SEX pilus can only be found on Gram (-) bacteria
Can endospores be found in gram (+) and gram (-) bacteria?
NO!

They are only a feature of Gram(+) RODS
What is the motor-like system that drives rotation in bacteria flagella?
Basal body
What specialized flagellan is found in spirochaetes?
Axial filament
Name the 2 general forms of flagella?
1. Polar
2. Peritrichous (multiple)
What specialized structure can be found in Treponema pallidum (syphillis) and Borrelia bergdorfer (Lyme disease)?
Axial filament--> flagella contained WITHIN the outer membrane
(Spirochetes)
What group of bacteria are Spirochetes categorized as?
Gram (-)
What kind of flagella does E.coli have?
Peritrichous flagella
What is the function of normal pili?
To secure the organism to a surface.
How does Neisseria gonorrhoeae attach itself to the epithelium of the urethra?
Produces pili
How can you abolish the virulence of a bacteria containing pili?
Mutate the bacteria so that it lacks a pili--> it will no longer be virulent if it can adhere to epithelial surfaces.
What is the function of a sex pilus?
To exchange genetic material
(conjugation)
Which 2 species of bacteria produce endospores?
1. Bacillus
2. Clostridium
(endospores are exclusive to gram(+) RODS)
What physical feature of gram(+) rods makes them VERY resistant to killing?
Endospores
Bacteria reproduce by _______, therefore growth is ________.
Fission
Exponential
What are the 4 phases of bacterial growth?
1. Lag (preparation for growth)
2. Exponential or log (actively dividing)
3. Stationary (nutrients are getting low, toxic by-products build up, cells shut down cell division)
4. Death (systems fail, membranes rupture)
What bacterial growth phase do penicillins target?
Exponential or log phase
Most bacteria that we will be concerned with in the clinic have optimal growth at 15-40*C and are termed __________.
Mesophiles
Medically relevant bacteria grow best at _____*C?
30-37*C
What kind of bacteria can shift their metabolism to grow aerobically or anaerobically?
Facultative anaerobes.
What kind of bacteria grow in the absence of oxygen?
Obligate anaerobes.
When an adverse environmental signal or condition encourages bacteria to adapt to survive, what has taken place?
"Selective pressure" has been applied to bacteria.
What does an organism have when it can preferentially overcome selective pressure?
"selective advantage"
(i.e. antibiotic resistance)
Non-programmed (random) changes in DNA nucleotide sequence.
Mutations
(can result in selective advantage)
Name the 3 mechanisms of bacterial genetic exchange.
1. Transformation
2. Conjugation
3. Transduction (generalized; specialized)
Transfer of "naked" DNA
Transformation
(often occurs when a cell lyses, but can also occur if an organism pumps out DNA into enviro)
Transfer requiring cell-to-cell contact
Conjugation
(involves exchange of plasmid DNA through sex pilus)
Transfer mediated by bacteriophage.
Transduction
(generalized or specialized)
What kind of genetic exchange mechanism will organisms containing plasmids have?
Conjugation
(plasmid contains gene for sex pilus)
For antibiotic resistance to be conferred through conjugation, what event must take place first (within the donor cell)?
Transposition
Chromosomal DNA will transpose/incorporate into plasmid DNA, so that during conjugation, plasmid AND chromo DNA get transferred.
How can a transfer of chromo DNA occur during generalized transduction?
Once lytic bacteriophage injects the viral DNA into a host cell, the viral DNA is replicated, and packaged before cell lyses.
However, a mistake can happen during the packaging of viral DNA, and some of the bacterial chromo DNA may accidentally get packaged. If this happens, then chromo DNA can be transerred during the next cycle of transduction.
Type of transduction that is mediated by lytic bacteriophage.
Generalized transduction
Type of transduction that is mediated by lysogenic bacteriophage.
Specialized transduction
During what type of transduction is a prophage made?
Specialized transduction
What type of transduction involves site-specific recombination? (phage seeks out specific site to incorporate itself into)
Specialized transduction
What's the main difference between generalized and specialized transduction?
In specialized transduction, the bacteriophage only carries/transfers specialized portions of bacterial genome into recipient--as opposed to generalized transduction where any random piece of chromo DNA can be transferred.
What type of organism initiated the development of Penicillinase-producing Neisseria gonorrhoeae (PPNG)?
NON-PATHOGEN
Haemophilus parainfluenzae
(part of normal flora in upper respiratory tract)

*Plasmid underwent transposition, which carried the AmpR gene into from the chromo DNA into the plasmid DNA.
Then, through conjugation, the AmpR was transferred to Haemophilus ducreyi
How did Haemophilus ducreyi transfer the AmpR gene to Neisseria gonorrhoeae (resulting in PPNG)?
Transformation
(released by dying cell)
List the order of events that led to PPNG.
1. Transposition occured in Haemophilus parainfluenzae (non-pathogen), rendering it the capacity to transfer AmpR via conjugation
2. Haemophilus ducreyi (STD) received AmpR and then transferred it via transformation
3. Neisseria gonorrhoeae (STD) received AmpR => VERY PATHOGENIC

*Non-pathogen lead to the development of PPNG
Why must you be careful when prescribing antibiotics?
*When you give a patient an antibiotic, you are not only treating the infection, but EVERY microorganism in their body. This allows an opportunity for selective advantage to take place.
What happens to bacteria that have a certain selective advantage when the selective pressure is removed?
Bacterial resistance decreases, but it NEVER goes to zero.
If a bacteria was previously sensitive to protein-synthesis inhibitor antibiotics, but is now becoming resistant, what has most likely happened?
The bacteria has undergone a genetic mutation, giving it a selective advantage.
Most likely a point mutation in one of the genes for ribosomal proteins.
What is the significance of the appearance of New Delhi metallo-beta-lactamase (NMD-1)?
It is a strain that has developed a resistance to carbapenems (which were developed to treat B-lactamase bacterial infections).
The resistance is due to the development of a carbapenamse.
First identified in Klebsiella pneumoniae
Now, strains are only sensitive to polymyxin and tigecycline
Describe the development of the New Delhi metallo-beta-lactamase (NDM-1).
1. First identified in Klebsiella pneumoniae
2. Spread via conjugation to Enterobacteriaceae.
3. Now in Acinetobacter baumannii
How fast did the appearance of NDM-1 bacteria spread across the globe?
9 months!
What is NMD-1 resistant to?
What can be used to treat it?
Resistant to:
B-lactams, carbapenems, fluoroquinolones, aminoglycosides

Only sensitive to:
Polymyxin and tigecycline