MUST KNOWS Flashcards
Prokaryote reproduce through?
binary fission (asexual)
bacterial growth is?
1) bacteria growth occurs via binary fission
2) increase in mass
3) increase in number
4) growth is rapid
during what phase is binary fission in?
** PREPARATION in Lag phase
**HAPPENS HERE: Log phase has exponential growth
** Stationary has no growth
Death
In binary fission, the septum formation in called? Formed by?
divisome
*formed by Fts proteins
Name the 3 important historical people?
Anton van Leeuwenhoek
Louis Pasteur
Robert Koch
Anton van Leeuwenhoek
- FIRST MICROBIOLOGIST (oral)
- first to discribe bacteria using a microscope
- MADE a microscope
What is terminal enzyme in fermentative pathway?
lactate dehydrogenase
What does lactate dehydrogenase do in biofilm?
lowers the pH by 2-3; this drop in pH causes the demineralization at tooth surface
Louis Pasteur
- discovered living organisms have D isomers
- discovered alcoholic fermentation
- disproved spontaneous generation
- developed vaccines for anthrax, cholera, rabies
Robert Koch
- Kochs postulates
- discovered that organisms were the cause of disease
- made method to grow ISOLATED colonies
describe koch postulates?
approach to determine which microorganisms causes disease
1) need infeted animal
2) must be isolated
3) same outcome in another aniamal
4) must be isolated again
define Quorum Sensing
process by which cells are able to detect the accumulation of a released signal and then change their behavior when the signal concentration exceeds a threshold level
What does Quorum Sensing allow cells to do?
survey their environment for cells of their own kind in order to SENSE POPULATIOn SIZE
What is a common quorum sensing inducer?
AHL
Acyl homoserine lactone
Quorum Sensing can sometimes lead to production of ?
virulence factors
How does AHL work?
1) cross membrane and boundby LuxR
2) AHL/LuxR complex binds to DNA regulatory region and activated transcription of QS genes
3) expression of lux-ligke genes results in wide range of activities like light production, virulence, motility, secretion
peptidoglycan is found in?
cell wall of bacteria
cell wall components of G+
peptidoglycan and teichois acid
cell wall components of G-
peptidoglycan and an outer membrane
peptidoglycan is found deeper in G- or G+ cell walls?
G- (because it has an outer membrane!!! IT IS A THINER layer as well)
peptidoglycan consists of? Linked by?
NAG and NAM (N-acetylglucosamine and N-acetylmuramic acid)
**linked by beta 1-4 glycosidic covalent bond
what is an enzyme our body produces that destroys peptidoglycan?
lysozyme
Transpeptidation concludes the synthesis of?
peptidoglycan
Vancomycin treats G+ infections by?
What about G-?
binding to the D-alanyl-D-alanine part of the PENTAPEPTIDE
- INACTIVE against G-
- obtained from streptomycess orientalis
What does penicillin do?
prevents cross-linkage of cell wall peptidoglycan
lysozyme targets?
beta 1-4 glycosidic covalent bond between NAM and NAG in peptidoglycan
Why would Vancomycin prevents transpaptidation?
it binds to the pantapeptide before the pentapeptide can bind to the tetrapeptide
Acid fast bacteria contain _____ acid layer where?
mycolic acid layer EXTERIOR to peptidoglycan, called the mycobacteria outer membrane
In addition to peptidoglycan, G- bacteria’s outer membrane contains?
LPS (lipopolysaccharide)
penicillin is more affective against G- or G+? Why?
G+
* bc G+ has thicker peptidoglycan
What bacteria controls S. mutans participation in biofilm participation?
Streptococcus salvarius
Streptococcus salvarius controls S. mutans how?
through production of FRUCTANASE
tooth decay is caused by what two bacteria?
streptococci sobrinus
streptococci mutans
dental plaque is a type of?
biofilm
biofilm is spread or started by?
planktonic bacteria that migrate
is the majority of a biofilm cells?
NO! it is EXTRACELLULAR
many dental procedures lead to?
bacteremia; entry of streptococcus mutens into bloodstream
What does S. mutans produce that is the cause of carries?
lactate dehydrogenase
tooth decay is promoted by diets?
high in sucrose
Mycobacteria vs mycoplasm
- *Mycobacteria= acid fast, mycolic acid
- *Mycoplasm= no cell wall, DO have sterols in membrane
- ***BOTH are major pathogens to humans and require special antibiotics (penicillin will NOT work)
penicillin vs bacitracin vs vancomysin inhibition
- -penicillin=blocks crossbridge formation bc transpeptedase enzyme binds to it
- -bacitracin= blocks bactoprenol transport of peptidoglycine unit
- Vancomysin= blocks pentapeptide from becoming tetrapeptide (so transpeptidation is never complete)
categories of antibiotics are based on?
what they inhibit in the bacteria cell; either protein, nucleic acid or peptidoglycan synthsis
describe Beta-lactam antibiotics? Examples?
have beta lactum ring in structure, focus on penicillin binding proteins that are involved in peptidoglycan synthesis
**inhibit cell wall synthsis by BLOCKING transpeptedase enzyme
Ex: transpepidase an carboxypeptidase
penicillin is the founding member to what group of antibiotics? G vs V?
Penicillium chrysogenum
- inhibit cell wall synthsis
- Penicillin G is inactivated by gastirc acid so it is used intravenously BUT penicillin V is more resistant to acid and is an oral drug
Cephalosporin drug
another B-lactam antibiotic but have a wider antibacterial spectrum than penicillins
What is the link between NAM/NAG vs NAM/NAM
- NAM/NAG= beta 1,4 glycosidic covalent bond
* NAM/NAM= crossbridge between different layers
biomes in the gut are involved in?
heath, personality, chronic inflammation, behavior, immune diseases
what is one unit of peptidoglycan?
1 NAM
1 NAG
1 peptide
*all in cytoplasm
what does bactophrenal do?
flips the unit of peptidoglycan from inside the cytosol to outside in the cell wall
Compare G+ and G-
- *G+ has more peptidoglycan and (lipo)teichoic acid
* *G- has less peptodoglycan, outermember, LPS, periplasmic space
Do broad spectrum antibiotics (specifically ones that target protein synthesis or DNA synthesis) will have a big impact on?
gut microbiome for a short period of time
Name antibiotics that target nucleic acid synthesis
- quinolones
- rifampin and rifabutin (produced from streptomyces)
tetracyclines causes what in dentistry?
perma nent tooth staining (mainly ins kids)
Name antibiotics that target cell wall synthesis
vancomycin (streptomycess orientalis)
bacitracin (Bacillus licheniformis)
In host parasite interactions, what is the M protein?
an attachment factor
acyl homoserine lactone… he said this twice in office. its has something to do with?
quorum sensing
Outer, middle and inner portions of LPS?
G-
- outer= are “O” specific
- middle=core polysaccarhides (glucose, galactose, NAG)
- inner= lacjs “O” secific, but has LIPID A which is the TOXIC part
fimbrae vs pili
- fimbrae= short
- pili= long, made of pilin protein
- both involved in conjugation
glucosyl transferase is found where? does what?
found in capsule/slime layer
*converts sucrose to glucose or fructose *needed to cause caries
what is an endospore?
highly resistant differentiated bacterial cell produced by GRAM POSITIVE bacteria
- layers: exosporium, coat, cortex, core wall
- produce small acid-soluble proteins for protection
- dipicolinic acid
what are thegenus/species for aerobic and anarobic endospore formined bacteria?
aerobic= Bacillis species anaerobic= clostridium species
genetic exchange through what 3 mechanisms?
conjugation, transformation, transduction
conjuation vs transduction vs transformation
- -conjugation=free plasmid moves from donor to recipient via a pilus
- -transformation= release of DNA fragments from dead donor cell, DNA enters recipient
- -transduction= transducing phage contains DNA and leaves dead donor, phage interacts with recipient
