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Microbiology Exam 2
Terms in this set (156)
what is caused by a number of bacteria to cause a disease in the host cell by disrupting host cell functions?
Cause hyperstimulation of the host immune response/activates immune system for systemic response (triggers fevers)
exotoxins can be made by what kind of bacteria?
secreted protein that alters host cell function, disrupts immune system, or kills host cells.
Staphyloccus alpha toxin produces ___________________________________, which causes RBC's to burst (hemolysis)
causes RBC's to burst, what the hemolysin protein from Staphyloccus alpha toxin does.
bacterial genomes are composed of what?
in _____________, the genome is a single circular chromosome
some bacterial genes are arranged in ________________.
a regulatory region to help fine-tune expression and make sure the genes are being activated when necessary and deactivated when necessary
a structural unit that has multiple genes that are laid out end to end that are all controlled by one single promoter
what is used during gene expression? (what the enzyme binds to, to actually express the genes that are next to it and make proteins)
every gene will lead to the production of how many specific proteins?
DNA molecules in addition to chromosomes of some bacteria
are plasmids bigger or smaller than chromosomes?
True or false: Plasmids are not truly essential, but they are generally useful
In bacterial genomes, __________ carry genes for conjugation pilus construction
In bacterial genomes, __________ carry genes for antibiotic resistance
____________ do carry genes, but the genes are not essential for the survival of the bacterial cell, but they can be very useful under certain conditions.
usually, the bacterial genome length is about _____________kb
how genes get expressed from information in DNA to make the functioning protein
a process cells use to make a copy of the entire DNA genome in preparation for cell division
makes mRNA from DNA genes
makes Proteins from the mRNA instructions
-10 & -35
promoter region of eukaryotes
after transcription, __________ leaves and we are left with RNA polymerase enzyme
The RNA polymerase will transcribe a stretch of RNA that is going to wind up on itself in a "hair-pin-like" structure that signals it can leave and the mRNA is complete.
there is a little sequence in the RNA structure that recruits another protein to travel along the RNA molecule and bump into the RNA polymerase, this is what triggers/signals that transcription is done.
product of transcription
used during translation to help build our proteins
major enzyme involved in translation
codons include _____ RNA molecules
each codon represents a different __________________
A three-nucleotide base sequence on tRNA.
A tRNA with an amino acid attached
always the start codon
initiation at ribosome binding site in bacteria
the methionine of bacteria
T&T occur ______________ in bacteria for any given time
what is always required for growth?
In bacteria most ___________ are only needed under a limited set of conditions.
To compete successfully with others, microbes cannot waste _______ making unneeded proteins
_____________ will only make the protein that they need at that moment
control of transcription
transcription can be regulated by protein repressors, activators, and alternative sigma factors
control of transcription initiation sequences that recognize specific proteins (ex: prevent ribosome binding)
control of proteins that are already made (ex: activate, deactivate or degrade the protein)
if a regulatory protein is going to ________ transcription, it is going to bind to the operator sequence that is between the promoter and target gene
If a regulatory protein is going to ___________, it is going to bind to a sequence that comes just before the promoter and helps recruit the polymerase to this region to increase transcription.
regulatory protein shuts down transcription
regulatory protein triggers transcription
Transcriptional activators needs a(n) ____________ to bind to it
both an activator protein and ligand are required to express the target gene
adding a ligand lets the target gene be expressed by removing the repressor
corepressor and repressor protein is required to stop expression of the DNA
No lactose operon in E. coli
repressor binds to operator and blocks transcription
Lactose operon present in E. coli
lactose binds to the receptor, receptor fails to bind to the operator and transcription occurs.
two component systems
extracellular signals trigger response inside the cell
detects the condition outside of the cell
works as a transcriptional regulatory protein where it can either activate or repress transcription of whatever target genes are inside of the cell
antibiotic resistance starts with a mutation in the ______________
transformation of horizontal gene transfer
bacteria is taking up DNA from the environment
conjugation of horizontal gene transfer
when one bacterial cell/living cell directly transfers DNA to a second living cell
Transduction of horizontal gene transfer
using a virus to move DNA from 1 bacterial cell to a second bacterial cell
horizontal gene transfer
a bacteria is getting a new gene or a new stretch of DNA in their own cell
When competent cells have all the genes and proteins it needs to import DNA. DNA is taken in the cell through a transformasome, single-strandedly
why be naturally competent?
Use DNA as food & repair own DNA using DNA from dead comrades
uses a (sex) pilus for cell-to-cell contact
In conjugation, the donor cell requires ______ factor
conjugation is good for the _____________, but bad for us (resistant strain)
DNA is transferred from one bacteria to another by a virus
random bacterial DNA is packaged inside a phage and transferred to a recipient cell. Most have viral phage DNA and some have bacterial genome packaged instead.
a highly specific part of the host genome is regularly incorporated into the virus
genetic relatedness arises from __________________________
natural selection "fixes" random mutations in genomes, leading to __________________
divergence creates a family tree of related organisms, known as _________________
organizing life into groups (taxa)
evolutionary history and relatedness of organisms
standardized system of naming living things (scientific name)
____________ is in italics and capitalized
______________ is in italics
Pathogen Evolution "melting pots"
Animal hosts, Shelter Species, Environment
Bacteria with Gram-Positive Cell Walls
Firmicutes & Actinobacteria
Occurs when nutrients/environmental conditions are poor.
-DNA replicates and gathers at one end
-Septum forms (like cell division)
-Thick exosporium forms (protein coat)
-Endospore is released & original cell degrades
Non-Endospore formin bacilli
Ferment milk and intracellular pathogens affect GI tract and nervous system.
-Ingested into host cell through phagocytosis
-listeria induces lysis of vesicle
-replication In cytoplasm
-use host cell actin to move
-infects neighboring cell directly
Alpha hemolysis on blood agar
shows a green-ish halo. Colonies that can only partially lyse the blood cells.
Beta hemolysis on blood agar
Clear zones around bacteria. Colonies can completely lyse the blood cells.
We can detect mollicutes through an _____________ stain
bacteria that lack a cell wall, which means that they do not have sram staining properties. They have no cell wall because they are obligate intracellular bacteria, they aren't exposed to a changing environment inside of a host.
Have a high G+C content. Broad group that includes antibiotic producers, decomposers in natural environments and pathogens. Some produce molecules with anti-tumor agents or immunosuppressants. Cell wall is WAXY.
what allows the actinobacteria to have a waxy cell wall?
a pathogen that can cause pneumonia (actinomycete)
Bacteria that have the ability to form a mycelia, which means more of a mat of long filamentous cells.
actinomycetes & other actinobacteria
Most diverse bacterial lineage. Gram negative cell walls, diversity of shapes, and a diversity of metabolisms.
Family of enteric (related to G.I. tract) gram negative bacilli. Rod shaped. Facultative anaerobes. Motile. Swimmer cell and Swarmer cell.
differentiation of enterobacteriaceae
swimmer cell to swarmer cell. Swarmer cells group together into rafts where they swim in the same direction, protecting cells towards the center. Allows to fight off immune response.
Obligate aerobic bacilli. Some use electron acceptors. Decomposers in soils. Natural recycling and soil turnover. Biofilms is cystic fibrosis patients
Intracellular pathogen that grows inside amoeba and in human macrophages. Transmission to humans: inhalation os aerosolized amoeba with Legionella inside
what bacteria causes the bubonic plague? (Uses rodents as a reservoir)
uses mineral oxidation for energy. Some grow in G.I. tracts. Many uses for humans and technology (oxidize sulfur (miners) and waste water treatment)
something that lives inside of the host and provides a benefit both ways
predatory attack on the host
Obligate anaerobes of the human colon. They break down toxins and give us 15% of the plant's caloric value & recycle bile acids. They also communicate with our immune system to help direct it (strengthening). Dangerous if spread during surgery!
spiral-shaped bacteria that have flexible walls and are capable of movement by flagella in the periplasm. Coiled-coil. Move in a rotational manner (like a screw), making it easier to flow through thick fluids.
subspecies _______________ evolved before pallidum
Cyanobacteria have _________________, so they are able to perform photosynthesis
oxygenic photoautotrophs. Fixes most of the CO2 in ecosystems, particularly in marine ecosystems
A symbiosis between cyanobacteria and fungi. They provide a significant portion of ground cover and food for animals in various environments.
fixing CO2 and N to build up nutrients for fungus
providing protection and shelter as well as nutrients for the cyanobacteria
obligate parasites or pathogens, can only grow inside a host. Absent or diminished cell walls, NOT mycoplasms. Persistent infection can lead to pelvic inflammatory disease.
allows nutrients and fluid to leak through the cell membrane. Produced by alpha toxin. Causes RBC's to burst open (hemolysis)
In a 2-subunit AB toxin, the ____ subunit is toxic
In a 2-subunit AB toxin, the ____ subunit binds to host cell receptors. These will form a channel into the cell.
Several AB toxins use _____________________ activity to inactivate or alter target host proteins. Adds NAD to inactivate.
In the AB toxin example of Anthrax Toxin, the B subunit is the ___________________________
causes cellular fluid loss
destroys regulatory cascades and cripples immune response => buildup of EF and LF
Made in the cell, but not released. Part of lipopolysaccharide in outer membrane of Gram negative cell.
Endotoxins are released when ___________ cells die
Activated __________________ promote a strong immune response, resulting in fever, activation of clotting factors, vasodilation, shock & potentially death.
Removing all living things (bacterial cells, fungi, spores and viruses) from surface.
Ex: surgical equipment
Killing the pathogens (inanimate object or surface). Disease-causing microbes are removed.
Ex: chair in dentist office
Killing only pathogens, using it on a living tissue
Ex: before surgery/ cutting begins
Reducing the number of microbes/pathogens on a surface by cleaning surface at the same time.
agents are designed to kill the microbes in question
stop those microbes from growing, but they are not going to immediately kill them. Prevent further growth, control a population.
Moderate temperature at 15 seconds. (ultra-high-temp pasteurization method available, 2 seconds)
in filtration, a pore size of ________ micrometers is effective against bacteria
In filtration, a pore size of ______ nanometers is necessary to remove viruses
works on foods and objects that cannot be filtered or heated without altering the food/object
___________ of DNA is a major factor to consider in irradiation, however, more DNA is easier to kill
cold temperatures __________ growth. Prevent microbes from growing, but they won't kill.
disrupt cell membranes
ethanol, iodine, chlorine
highly reactive compounds that damage proteins, lipids, and DNA
Generally not the first choice because it is combustable and dangerous. Kill microbes that are on the object. (EtO)
Antimicrobial Touch Surfaces
Surfaces made of metal that disrupt the bacterial cell membranes. Mechanism of how this works in unclear. (ex: hospital doors, handrails, bedrails, etc.)
the antibiotic needs to target a pathogen or bacteria and be toxic to them, but not affect the host cell. Otherwise we are damaging ourselves in the process.
broad spectrum antibiotics
antibiotics that affect a broad range of gram-positive or gram-negative bacteria
Narrow spectrum antibiotics
sensitive to only a few types of bacteria (either gram positive OR gram negative)
Zone of inhibition
Area where bacteria does not grow due to an antibiotic
The lowest concentration of the antibiotic that prevents or inhibits bacterial growth.
MIC strip test
the concentration of antibiotic where growth meets the strip
drug concentration has to be ____________(higher/lower) than MIc during treatment
minimum dose that stops pathogen growth
maximum dose that is tolerated by the patient
ration between toxic dose and therapeutic dose (toxic/therapeutic). The higher the number, the safer the drug is.
a really good target for antibiotics
metabolized by microaerophillic and anaerobic bacteria, not aerobes
Inhibit DNA synthesis by blocking DNA gyrase, preventing the bacteria from regulating supercoiling
binds to RNA polymerase and blocks transcription
Prevent 70S subunit formation
Inhibits translocation and causes misreading of mRNA
Prevent aminoacyl-tRNA entry into the A site
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