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190 Cards in this Set
- Front
- Back
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Cytoplasm |
Dense fluid encased by the cell membrane; it is the site of many of the cell's biomechanical and synthetic activities |
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Nucleoid |
The basophilic nuclear region or nuclear body that contains the bacterial chromosome |
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Chromosome |
Tightly coiled body in cells that are the primary site of genes |
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ribosome |
A bilobed macromolecular complex of ribonucleoprotein that coordinates the codons of mRNA with tRNA anticodons and, inso doing, constitutes the peptide assembly site |
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Flagellum |
a structure used to propel an org. through fluid |
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Pili |
small, stiff filamentous appendages in gram negative bact. that function in DNA exchange during bact. conjugation. |
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Fimbriae |
Short, numerous-surface appendage on some bact. that provides adhesion, not locomotion. |
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glycocalyx |
filamentous network of carbohydrate-rich molecules that coats cells |
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cell wall |
in bacteria: a rigid structure made of peptidoglycan that lies just outside the cytoplasmic membrane; eukaryotes also have cell walls, but may be made of a variety of materials |
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peptidoglycan |
a network of polysaccharide chains cross-linked by short peptides that forms the rigid part of bacteria walls. Gram negative have a smaller amount of this rigid structure than Gram positive. |
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Cell envelope of a Gram + bacteria |
an "open-faced sandwich". 2 layers: 1. thick cell wall composed of peptidoglycan. 2. cytoplasmic membrane (inner most) |
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Cell envelope of a Gram - bacteria |
a "complete sandwich". 3 layers: 1. outer membrane. 2. thin cell wall. 3. cytoplasmic membrane (innermost) |
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What is part of a gram negative bacteria cell envelope, but not a gram positive cell envelope? |
the outer membrane |
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Outer membrane: |
an additional membrane in Gram negative bacteria; a lipid bilateral containing specialized proteins and polysaccharides. Located outside of the cell wall. |
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Cytoplasmic membrane: |
lipid bilayer that encloses the cytoplasm of bacteria cells |
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lipopolusaccharide |
molecular complex of lipid and carbohydrates found in the bacterial cell wall. LPS of Gram negative bacteria is an endotoxin that causes shock and fever |
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virulence factor |
a microbe's structures or capabilites that allow it to establish itself in a host and cause damage |
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infectious dose |
amount of a pathogen that is needed to cause infection of a pathogen (minimum #) |
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exoenzyme |
extracellular enzyme for hydrolysis. It functions in decomposition of organic debris and can be a factor in invasiveness of pathogen |
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exotoxin |
a toxin (protein) that is secreted and acts upon a specific cellular target (botulin=botulism) |
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endotoxin |
a bacterial toxin not usually released. In a Gram negative bacteria's cell wall that causes shock and fever |
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Selective toxicity |
property of an antimicrobial agent to be highly toxic against it's target microbe while being far less toxic to other cells, especially those of the host |
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Spectrum of activity for antibiotics |
the range of bacterial types against which the antibiotic is effective. "Broad spectrum" is used for Gram negative bacteria- it kills everything good and bad |
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Minimun inhibitory concentration (MIC) |
The smallest concentration of drug needed to viably control microbial growth. |
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Organization of a bacterial cell |
Outer capsule - pili, fimbriae, flagellum Cell Wall Plasma membrane cytoplasm- ribosomes, nucleoid |
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Characteristics of a prokaryote (bacterial cell) |
spherical or cylindrical in shape, cytoplasmic membrane, chromosomes made from DNA, ribosomes for protein synthesis, reproduce from progeny cells, obtain energy from their enviro. |
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All bacteria cells have: |
cell membrane, cytoplasm, ribosomes, one or a few chromosomes |
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Most bacteria cells have: |
cell wall, surface coating (glycocalyx) |
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Some bacteria cells have: |
flagella, pili, fimbriae, capsules, slime layers, endospores |
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different btwn Gram positive cell membrane and Gram negative cell membrane: |
Gram positive has 2 layers: a thick cell wall and cytoplasmic membrane. Gram negative has 3 layers: an outer membrane, a thin cell wall, and cytoplasmic membrane |
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Lipopolysaccharides are where in the bacterial cell? |
outer membrane |
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What is the dominant antigen in the lipopolysaccharide of a Gram negative cell? |
O Antigen (V.chorlerae O139, E.coli O157) |
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Are endotoxins an inner or outer component of bacterial cells? |
outer component |
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What are the functions of the cell membrane? |
energy reactions (ATP synthesis, proton and ion gradients) Regulates transport (selectively permeable membrane) Secretion |
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What are the 3 parts of flagellum? |
1. filament (long flagellum) 2. hook (attached to a motor) 3. basal body |
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What is monotrichous? |
a single flagellum |
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What is lophotrikhous? |
small bunches of tufts of flagella emerging from the same site |
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What is peritrichous? |
flagella dispersed randomly over the structure of the cell (E.coli and Salmonella) |
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What is amphitrichous? |
A single flagella coming from each end of the cell |
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How do flagellum move? Chaotic tumbles or straight lines? |
They go between chaotic tumbles and runs to get where they want to go "a drunkards walk". Fewer tumbles than runs when moving towards the attraction, the closer they are the more runs they do. It senses the concentration of it's attractant. (Na, O2) |
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What are the 2 prokaryotic appendages? |
fimbriae-abundant (used for attachment) and pili-fewer(used for attachment, genetic exchange and motility). These are important for infection and interaction with the host |
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What is a slime layer? |
A type of glycocalyx. A loose shield that protects some bacteria from loss of water and nutrients |
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What is a capsule? |
Occurs when they glycocalyx is bound more tightly to the cell and is denser and thicker than slime layer |
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How can you identify btwn a slime layer and a capsule? |
By how sugary or loose the cell covering is. |
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What is the function of the glycocalyx? |
It is important for adhesion and the formation of biofilms |
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Why are slime layers good for infection? |
They allow the bacteria to slide around our defences, it's hard for our immune cells to grab the invader, they can also cross barriers in our cells. |
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What 2 things is the cell envelope made of? |
the cell wall and cell membrane |
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What does the cell envelope do? |
protects the cell from the enviro. Keeps cytoplasm contained The site of many metabolic processes |
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What type of cells have 2 cell membranes? |
Gram negative bacterial cells |
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What is the cell wall of bacteria made of? |
peptidoglycan-small strings of amino acids connecting long chains of sugars-long strings of sugars linked by peptides-some of our best antibiotics target the cross link and either break it or prevent it from forming.-humans don't have cell walls like this, this is why it's good that antibiotics target this. |
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What types of the body's defences block the sugar chains in bacterial cell walls? |
lysozymes, tears, sweat- it degrades bacterial cell walls |
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What is the function of the bacterial cell wall? |
It keeps the cell from rupturing. |
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Difference btwn Gram + and Gram - cell walls: |
Gram +: thick sheath of peptidoglycan, contains tightly bound polysaccharides Gram - : thin sheath of peptidoglycan, periplasmic space surrounds the peptidoglycan |
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Why don't many antibiotics work to get rid of Gram - bacteria? |
B/c it can't destroy the cell wall because of it's outer layer of lipopolysaccharides. Antibiotics need to get through pores on Gram - |
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Why are antibiotics good at targeting Gram + bacteria? |
The antibiotic can interact directly with the cell wall. |
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How many chromosomes do bacteria usually have? |
Usually a single chromosome (single circular strand of DNA). But Vibrio has 2 |
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What is the goal of antimicrobial drugs? |
disrupt the cell processes or structures of bacteria, fungi and protozoa. Or inhibit virus replication (antivirals) |
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What do most antimicrobial drugs do? |
Interfere with the function of enzymes required to synthesize and assemble macromolecules. Or destroy structures already formed in the cell. |
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What does this mean: drugs should be selectively toxic? |
They should kill or inhibit microbial cells without damaging host tissues |
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What is low selective toxicity? |
antimicrobials that are toxic to humans. Used when someone is on their death bed and this is a last resort |
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What are the 5 ways that antibiotics can target a bacteria cell? |
1. Inhibit protein synthesis acting on ribosomes 2. Cell wall inhibitors: block synthesis and and repair 3. Cell membrane: Cause loss of selective permeability 4. DNA/RNA: inhibit replication and transcription, inhibit gyrase (unwinding enzyme), inhibit RNA polymerase 5. Folic acid synthesis in the cytoplasm:block pathways and inhibit metabolism |
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What are examples of antibiotics that inhibit protein synthesis acting on ribosomes? |
Erythromycin (and other mycins), Tetracyclines (and other cyclones) |
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What are examples of antibiotics that inhibit cell walls? |
beta lactam antibiotics: penicillins, cephalosporins (works for bacteria resistant to penicillin), carbapenems, vancomycin. blocks the synthesis of the cell wall. |
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What antibiotics cause loss of selective permeability of the cell membrane? |
polymyxins, daptomycin
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What antibiotics inhibit replication and transcription of DNA? |
Quinolones |
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What antibiotics inhibit RNA polymerases? |
Rifampin |
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What antibiotics block pathways and inhibit metabolism (folic acid synthesis in the cytoplasm)? |
Sulfa drugs |
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What is ESBL? |
extended spectrum beta lactamases. They are very problematic b/c there are only a few antibiotics that can be used against them. Beta lactamase is an enzyme made by the bacterium. |
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How do beta lactam antibiotics function? |
They block the cross-linking of cell wall peptides. |
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Do all antibiotics have a beta lactam ring? |
No, only beta lactam antibiotics do. |
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Why isn't the cell membrane always a good target? |
Because all organisms have membranes. They have poor selective toxicity. Bacteria cel membranes are similar to human cell membranes. |
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What antibiotic is used to target the cell membrane? |
Polymyxins. They work against Gram - bacterium b/c of LPS. Usually used topically as a cream. |
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What antibiotics are used to inhibit DNA function? (DNA gyrase inhibitors) |
Quinolones Ciprofloxacin: Used for protection of anthrax in 2001 Gyrates are used to coil DNA and helps it fit into cells. Bacterial gyrases are different than humans. The antibiotic can differentiate btwn bacterial and human gyrases. |
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What antibiotic is used to inhibit RNA synthesis? |
Rifampin: it binds to RNA polymerase (makes RNA). It is specific for bacteria, it is useful for TB. Ribosomes bind to RNA and make proteins. |
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Which antibiotics block the enzyme function? (inhibiting folic acid production) |
Sulfa drugs. Our body gets folic acid (Vit B9)from our diet, our cells don't make it. Bacteria and protozoan cells have to produce their own folic acid from PABA. Sulfa drugs inhibit the bacteria and protozoan cells from producing folic acid. |
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What are the 6 steps of viral replication? |
1. Adsorption 2. Penetration 3. Uncoating and freeing viral RNA 4. Synthesis (replication and protein production) 5. Assembly (viral spike proteins are inserted into the cell membrane) 6. Release - ready to infect another cell |
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What is viral latency? |
When a virus is inside the human genome but not causing any harm. It has the potential to make more viruses and cause harm |
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What are 3 ways antivirals work against viruses? |
1. Inhibition of viral entry by blocking receptors, adsorption and block viral release (Tamiflu and Fuzeon) 2. Inhibition of nucleic acid synthesis by blocking reverse transcriptase (blocks the enzyme) 3. Inhibition of viral assembly and release (viral protease) - our cells don't use proteases |
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Where is normal biota located on the human body? |
skin, resp tract, GI tract, mouth, urethra, vagina, eyes |
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What are the factors that weaken host defences and increase susceptibility to infection? |
Age (young and old), decreased immunity (AIDS), sx and organ transplant, underlying disease, immunosuppressive drugs, physical and mental stress, other infections |
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What is an infection? |
A condition in which pathogenic microbes penetrate host defences, enter tissues and multiply |
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What is an infectious disease? |
A disruption of tissue or organ (pathologic state) caused by microbes or their products |
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What are signs of infection? |
objective evidence: fever, septicemia, microbes in tissue fluids, chest sounds
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What are symptoms of infection? |
Subjective evidence: chills, pain, aches, malaise, fatigue |
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What are the 3 processes of infection? |
establishment, spread, disease effects |
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What are the 5 patterns of infection? |
1. localized - 1 area (redness) 2. systemic - spread to several sites via blood 3. focal - infectious agent leaves a focal infection and is carried to other tissues 4. mixed - multiple species contribute to the infection (dog bite)- polymicrobial 5. primary-secondary - successive. One occurs b/c of the other. Usually b/c of a weakened immune system. |
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What is a pathogen? |
able to cause disease in a susceptible host |
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What determines whether a microorganism can establish an infection? |
Pathogenicity, dose, condition of the host, portal of entry |
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What are true pathogens? |
Their lifestyle depends on infecting the host. They attack healthy people |
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What is an opportunistic pathogen? |
any normal flora that picks up genes that can cause infection. Only cause disease when given the opportunity. Often d/t breakdown in immune system or immature immune system |
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What is the #1 portal of entry for pathogen? |
The resp tract |
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What is virulence/pathogenicity? |
The ability to cause infection. Occurs |
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What is a virulence factor? |
microbial components that contribute to the ability to cause disease in a susceptible host |
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What do pathogens use for attachment and motility? |
pili, fimbriae, capsule, flagella |
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true or false: vibrio toxin is a virulence factor? |
True |
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What is the difference btwn the adsorption of bacteria and viruses? |
Bacteria use pili and fimbriae and viruses use spikes |
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What do exoenzymes do? |
break down and inflict damage on tissues or dissolve the host's defence barriers |
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What is toxigenicity? |
The ability to produce toxins |
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What is toxinoses? |
a variety of diseases caused by toxigenicity |
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What is toxemias? |
toxinoses in which the toxin is spread by the blood from the site of infection |
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What is intoxication? |
boxiness caused by ingestion of toxins (botulism) |
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What do exotoxins do? |
target organs are damaged (heart, lungs, m.s, blood cells. |
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What do endotoxins do? |
Cause fever, shock, malaise, aches |
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What does the vibrio toxin do? |
Causes sever water loss |
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What is a gene? |
A segment of DNA that codes for a protein or RNA |
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What is a mutation? |
a permanent, heritable change in genetic information. |
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What is transcription? |
DNA code is converted to RNA directed by RNA polymerase. |
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What is translation? |
The synthesis of proteins using RNA as a template. |
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What is a genotype? |
genetic makeup of an organism. |
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What is a phenotype? |
observable characteristics of an organism |
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What is conjugation? |
in bacteria: the contact btwn donor and recipient cells associated with the transfer of genetic material. ("sex") |
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What is Transduction? |
The transfer of genetic material from one bact. to another by a bacteriophage. |
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What is transformation? |
in microbial genetics: the transfer of genetic material contained in "naked" DNA fragments from a donor cell to a competent recipient cell. |
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What is a plasmid? |
small, circular, DNA molecules. Often carry antibiotic resistance genes. Can move btwn different species and this spreads antibiotic resistance to different pathogens. Has non-essential genes. |
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What is MIC? |
minimun inhibitory concentration. The smallest concentration of a drug needed to visibly control microbial growth. |
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What is a cytokine? |
a chemical substance produced by WBC and tissue cells that regulates development, inflammation and immunity. |
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What is an interferon? |
IFN: natural human chemical that inhibits viral replication; used therapeutically to combat viral infections and cancer. |
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What is a complement? |
In immunology: serum protein components that act in a definite sequence when set in motion either by an antigen-antibody complex or by factors of the alternative pathway. |
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What is sexual reproduction? |
Occurs in sexual organisms (humans). Requires 2 parents, generates new combinations of parental genes, sex is necessary for reproduction |
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What is asexual reproduction? |
One cell divides into 2 identical daughter cells. Each daughter gets a full copy of the parent's genes. There is no gene mixing. Bacteria reproduce asexually. |
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How do bacteria and viruses evolve? |
Random mutations, SNP, horizontal gene transfer; evolutionary jumps, antibiotic resistance. |
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What is horizontal gene transfer? |
HGT: genes move from donor to recipient of asexual organisms. Only a small # of genes transfer. This is NOT sex. |
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How does horizontal gene transfer affect bacterial evolution? |
influences bacterium's lifestyle, potential to invade a new niche and speciate, many may move into mammals |
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How often do genes go through HGT in bact.? |
Depends on the species - but rare. Happens more by plasmids. Plasmids can be gained but then lost. |
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What are the 3 mechanisms of HGT? |
1. conjugation-direct HGT (in contact during exchange) 2. transformation-indirect HGT (not in contact during exchange) 3. transduction - indirect HGT-donor is lysed by bacterial cell. |
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What is natural transformation? |
A pathogen sometimes uses DNA from other dead cells for food. Sometimes they pick up genes by doing this. And this causes a conversion of serogroups and can cause the new pathogen to be harmful. |
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What is MRSA? |
Methicillin resistant staph aureus |
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What is VRE? |
vancomycin-resistant enterococcus. |
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What is CRE? |
carbapenem-resistant enterobacteriaceae |
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What is NDM? |
New Delhi metallo beta lactamase |
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What is C.Diff? |
Clostridium Difficile |
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What are examples of your body's first line of defence? |
skin, mucus, cilia, tears, saliva, secretions (urinary tract always being flushed), macrophage, sebaceous secretions, lysozyme (tears), lactic acids, pH of stomach acids, digestive juices/bile, pH of vagina, normal flora. |
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What is the main way that bacteria enter the body? |
Resp tract |
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What is the body's 2nd line of defence? |
Proteins and peptides, WBC |
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What is the body's 3rd line of defence? |
Immune system |
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What is a PAMP? |
Pathogen associated molecular pattern |
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What is a microbiota? |
microbes that live in communities on the body |
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What is a microbiome? |
A collection of organisms and their genes/functions (the genes determine their functions) |
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What is metagenomics? |
study of all genomes in an ecological niche. Different types of genomes. |
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What are 5 ways that bacteria can develop drug resistance? |
1. drug inactivation-the drug is changed 2. decreased permeability-drug can't bind 3. drug binding sit is altered- drug can't bind 4. drug pumps-drug enters and is pumped out 5. alternative metabolic pathways- drug binds incorrectly |
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The sum total of the genetic material of a cell is its: a. genes b. genome c. proteome d. transcriptase |
b. genome |
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A specific segment of DNA that contains the necessary code to make a protein or RNA molecule is a: a. gene b. chromosome c. VNTR d. z band |
a. gene |
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True or False: RNA molecules are circular and double-stranded, as compared to the linear single-stranded structure of DNA molecules. |
False. |
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A permanent change in the DNA base sequence is a: a. mutation b. methylation c. primer d. catalyst |
a. mutation |
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The transfer of naked DNA from one cell to another |
Transformation |
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DNA transfer from a donor bacterium to a recipient via sex pili |
conjugation |
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DNA transfer from one bacterial cell to another cell via bacteriophage |
transduction |
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True or false: Mutations are the primary source of genetic variation that makes evolution possible. |
True |
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What 2 drugs are protein synthesis inhibitors and act on ribosomes? |
Erythromycin, aminoglycosides |
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Which drugs work to stop folic acid synthesis of a bacteria? |
Sulfonamides (sulfa drugs) |
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What drugs are cell wall inhibitors? |
penicillins, cephalosporins |
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What drugs break down the cell membrane? |
polymixins |
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What drugs affect the DNA and RNA of bacteria? |
rifampin, quinolones |
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True or false: Environmental microbes are now recognized as important reservoirs of antimicrobial resistance genes. |
True |
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What are the 5 mechanisms of antimicrobial resistance? |
1. Enzymatic inactivation of the antibiotic. 2.Antibiotic efflux pumps pump the antibiotic out of the cell. 3.Altered target site, such that the antibiotic can no longer bind to the target. 4.Microbe uses an alternative pathway to circumvent the blocked pathway. 5.Decreased permeability to the antibiotic. |
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The production of beta-lactamases is an example of this mechanism of drug resistance: a. drug inactivation b.increased drug permeability c. increased drug binding sites d. altered internal metabolic pathway |
a. drug inactivation |
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What are examples of your bodies first line of defences? |
skin, mucus, cilia, (physical and chemical barriers). Non specific |
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What are examples of your bodies second line of defences? |
antimicrobial proteins, antimicrobial peptides, WBCs (inflammation process) neutrophils and eosinophils. Specific |
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What are examples of your bodies third line of defences? |
B cells and T cells. B cells produce antibodies. |
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What are the 4 steps of the inflammatory reaction? |
1. injury/immediate reaction-vasodilation 2. Vascular reactions-coagulation 3. edema and pus formation 4. resolution and scar formation |
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What are 3 characteristics exhibited by all bacteria? |
Chromosome Ribosomes Cell membrane |
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What are the 5 structures possessed by some but not all bacteria? |
flagella, endospores, pili, fimbriae, glycocalyx |
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True or false: A bacterial species is equivalent to that of an animal species, because both exhibit a common form of sexual reproduction. |
False |
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A major component of gram-negative outer membranes, lipopolysaccharide can stimulate shock and fever and is referred to as: a.phospholipid b.endotoxin c.exotoxin d.glycosphingolipid |
b. endotoxin |
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The movement of bacteria either toward or away from a chemical stimulus is referred to as: a.chemotaxis b.phototropism c.geotropism d.hydrotaxis |
a. chemotaxis |
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Choose the bacterial appendage whose only role is to enable bacteria to stick to one another, to inanimate surfaces, and to host cells. a.Pili b.Fimbriae c.Flagella d.Axial filaments e.Cell wall |
b. fimbriae |
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Choose the term that best describes how bacteria respond to chemical attractants. a.Chemical attractants cause bacterial cells to grow additional flagella. b.Chemical attractants speed up the rotation rate of flagella. c.Chemical attractants inhibit tumbles, enabling bacteria to make faster progress toward the stimulus. d.Chemical attractants cause flagella to rotate clockwise. |
c. chemical attractant inhibit tumbles, enabling bacteria to make faster progress toward the stimulus. |
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Select those structures that are found in a gram-negative cell envelope. a.Thick layer of peptidoglycan b.Outer membrane c.Periplasmic space d.Cell membrane e.Teichoic acids f.Lipopolysaccharide g.Lipoteichoic acids h.Thin layer of peptidoglycan |
b. outer membrane c. periplasmic space d. cell membrane f. Lipopolysaccharides h. thin layer of peptidoglycan |
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Choose the component that provides for a stronger cell wall structure in gram-positive cells, compared togram-negative cells. a.Thick peptidoglycan layer b.Lipopolysaccharide c.Outer membrane d. Teichoic acids e.Phospholipids |
a. thich peptidoglycan layer |
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What 4 drugs target the cell wall of a bacteria? |
Penicillins, cephalosporins, carbapenems, vancomycin |
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What 4 drugs target protein synthesis of a bacteria? |
aminoglycosides, tetracylines, glyclylcycines,erythromycin |
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What type of drugs target folic acid synthesis of bacteria? |
Sulfonamides (sulfa drugs) |
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What 2 drugs target DNA or RNA of bacteria? |
fluroquinolones (ciprofloxacin), rifampin |
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What drugs target cell membranes of bacteria? |
polymyxins |
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What is microbicidal? |
kills microorganisms |
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What is microbistatic? |
inhibits the growth of microorganisms |
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Select the two correct answers to test your understanding of the primary goals of antimicrobial treatment. a.To destroy the infective agent b.To kill malignant cells c.To be nontoxic to the host and produce no side-effects d.To identify the cause of infection e.To alter the normal microbiota of the patient |
a. to destroy the infective agent c. to be nontoxic to the host and produce no side effects |
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True or False:An effective antimicrobial drug will only destroy 30% of the host's cells. |
False |
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The feature of an antimicrobial that makes it kill or inhibit microbes yet be harmless to the host is referred to as: a.limited toxicity b.selective toxicity c.broad-spectrum toxicity d.narrow-spectrum toxicity |
b. selective toxicity |
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Select which of the following represents a correct pairing of antimicrobial drug and cellular target: a.penicillins, ribosomes b.cephalosporins, cell wall c.tetracylcines, cell membrane d.polymyxins, DNA/RNA |
b. cephalosporins, cell wall |
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Select the major targets of antimicrobial therapy: a.cell membrane structure and/or function b.cell wall synthesis c.flagellar assembly d.DNA/RNA structure and/or function e.protein synthesis f.ATP synthesis g.folic acid synthesis |
a. cell membrane structure and/or function b. cell wall synthesis d. DNA/RNA structure and/or function e. protein synthesis g. folic acid synthesis |
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The fluoroquinolones, or quinolone drugs, are a group of antimicrobials that inhibit: a.nucleic acid structure and/or function b.cell wall synthesis c.ribosome activity d.cell membrane structure and/or function |
a. nucleic acid structure and/or function |
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True or False: Polymyxin drugs are very broad-spectrum antibiotics that exhibit high selective toxicity. |
False |
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Select the two ways in which microorganisms acquire antimicrobial resistance. a.Spontaneous mutation b.Antibiotic-induced mutations c.Transfer of genes from their human or animal host d.Transfer of genes from other microorganisms e.Through nutritional starvation |
a. spontaneous mutation d. Transfer of genes from other microorganisms (transformation) |
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What is colonization? |
Presence of organisms living in or on the body, but not causing any pathology. |
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What is infection? |
Pathogenic microorganisms penetrate the host defenses, enter the tissues, and multiply. |
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What is infectious disease? |
Disruption of a tissue or organ caused by microbes or their products. |
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True or false:Colonization of a body tissue by microbes always results in the establishment of disease. |
False |
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The ability of a nonpathogen or weakly pathogenic microorganism to cause disease primarily in an immunocompromised host is termed: a.virulence b.pathogenicity c.opportunism d.antagonism |
c. opportunism |
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The minimum number of microorganisms necessary to enter the body and establish infection is termed the: a. minimal dose b.infectious dose c.virulence dose d.disease dose |
b. infectious dose |
