Quiz 2 study guide flashcards
What is the main structural component of bacterial cell walls
Peptidoglycan
What is peptidoglycan synthesis disrupted by
Penicillins, cephalosporins, vancomyocin
What are the characteristics of gram-positive bacteria
Peptidoglycan has a thick layer, purple color
What are the charachteristics of gram-negative bacteria
Thin peptidoglycan layer, surrounded by outer membrane anchored to peptidoglycan
Which bacteria (gram negative or positive) has Lipid A
Gram-negative, can cause sepsis when treating gram-negative bacteria
What are bacterial capsules
-external to the cell wall, polysacchardies that have a silmey surface
- Protects the bacteria from phagocytosis by host immune cells
What are capsules made of
EPS (extracellular polymeric substance)
- Biofilm (slimey layer)
- Absorbs lots of water to resist desiccation
What is a common type of capsule/bacteria with a capsule?
Streptococcus pneumonia capsule
What are the 3 basic shapes of bacteria
bacillis, cocci, spirochetes
What shape do cocci reproducing in one plane produce
diplococci or streptococi
What shape do cocci reproducing in more than one plane produce
Staphylococci
What are the nutritional requirements for growth of bacteria
carbon, oxygen, nitrogen, hydrogen, phospherous, sulfer, potassium
What are the two types of bacterial metabolism
aerobic- final electron acceptor is O2 (38 ATP)
anaerobic- final electron acceptor is organic (2 ATP) or inorganic molecule (34 ATP)
What is the difference between an obligate and facultative anaerobe
Facultative organisms can swap between aerobic and anaerobic metabolism, obligate anaerobes absolutely need NO oxygen to metabolize
What are the 4 stages of bacterial growth
- lag phase- no cell division
- logarithmic phase- rapid cell division
- stationary phase- depleted nutrients, slow to no cell division
- death phase- toxic waste accumulates, death rate >division rate.
What is rate of bacterial growth dependent on
- the species and
- the levels of nutrients available in the environment
What is the MOI for ciprofloxacin
inhibit DNA replication
What is the MOI for penacillins, vancomyocin, and cephalosporins
Inhibit peptidoglycan cell wall synthesis
What is the process of binary fission
- DNA chromosome replicates
- Replicated chromosomes seperate
- Cell wall forms in the middle of the cell
- Cell seperates and forms 2 identical cells
What is the error rate in bacterial DNA polymerase
Very accurate- Only 1 mistake in every 10^10 base pairs
What is the function of DNA polymerase 3 in replication
proofreads the replication as it goes
What are operons and their significance
Operons are clusters of genes that are transcribed together and translated into more than one protein
What is unique about bacterial transcription
bacteria can change the rate of the transcription of genes to fill different needs (can pick the protein they need, i.e. pilli or toxin)
Where does transcription and translation occur in prokaryotes
- Transcription and translation occur at the same time in the cytoplasm (in 70s ribosomes, good target for antibiotics)
Where does transcription and translation occur in eukaryotes
Transcription: nucleus. Translation: cytoplasm/ Rough ER.
Use 80(s?) ribosomes
What is quorum sensing
specific gene transcription is activated in response to concentration of bacteria
- pathogenic activity of bacteria begins when cell numbers reach a certain threshold
Which bacteria typically form endospores
clostridium and bacillus grow endospores when they can’t grow in an environment
What is an endospore
A complex, multilayered coat sourrounding bacterial cell
- Can remain in dormant state for years and then revert to normal bacteria under good conditions
Where are endospores commonly found
in soils
What are the 3 types of gene transfer
- Conjugation: transfer of DNA from one to another through sex pillus
- Transformation: uptake of DNA in the environment
- Transduction: Transfer of genetic information by infection iwth bacteriophage and mispacking of host DNA into virons
What is the difference between generalized and specialized transduction
Generalized: bacteriophages pick up a portion of host’s genome
Specialized: bacteriophages pick up specific, adjacent portions of host’s DNA (not plasmid)
Group A streptococci disesases and transmission
- Produce exotoxin, has capsule
-cause skin infection, necrotizing fascitis, TSS, post surgery complication
-Transmission: airborne, direct contact
Streptococcus pneumoniae diseases and transmission
encapsulated, cause pnumonia, meningitis, ear infection, bacterimia, sinusitis
Transmission: Resperatory droplets
Enterococcus transmission and diseases
Normal flora in GI tract.
Cause UTI’s, bacteremia, endocarditis, wound infections.
Transmission: Endogeneous infections
Staphylococcus aureus charachteristics/ disease/ treatment
- aerobic and anaerobic resp.
- Boils, skin sepsis, post op wound infection, food poisioning, TSS
- Transmission: Natural habitat, nose.
-Treat with penicillins, muprocin, methicillin/vancomyocin
