Exchange of nucleotide sequences often occurs between | Homologous sequences |
Cells with DNA molecules that contain new nucleotide sequences | recombinants |
What seals nicked ends in new combinations | ligase |
Difference between horizontal and vertical gene tranfer | Vertical gene transfer is passing of genes from parent to next generation whereas horizontal is between two different mature bacteria |
3 types of horizontal gene transfer | Transformation, transduction, conjugation |
Define transformation | Bacteria takes up naked DNA from environment |
Was the live R or S strain supposed to kill the mice | S strain |
Define transduction | Transfer of DNA via replicating virus |
The virus in transduction must be able to infect what | donor and reciepient cells |
Types of transduction | generalized and specialized |
What do phages enzymes do upon entering host cell | degrades host cell DNA |
what happens after host DNA degradation | new phages are produced to engulf phage DNA |
What else happens due to this | Host DNA is taken by accident |
define conjugation | Transfer of F+ plasmid |
How does F+ attach to F- cell | Using its sex pilus |
What is an HFR cell | F+ incorporated in host DNA |
End result of HFR transfer | Reciepient is still F- |
Segments of DNA that move from one location to another in the same or different molecule | Transposons |
Transposons all contain | palindromic sequences at end |
Frameshift insertions that occur due to transposons | Transposition |
Two types of transposons | jumping and replication transposons |
Which type of transposon cannot transfer onto a plasmid | Jumping transposon |
Type of transposon that contains genes not related to transposition | complex transposon |
simplest transposon contains what (2) | one gene, 2inverted repeats |
Difference between cide and statis/static | Cide is killing whereas statis is just inhibiting growth |
Reduction of pathogens and viruses on living tissues | Antisepsis |
2 examples of antisepsis | iodine and alcohol |
Due to antisepsis being used on living tissues, what precaution is taken | Its strength is reduced |
An environment or procedure free from pathogenic contaminants | Aseptic |
Examples of cides | fungicides, germicides and virucides |
Examples of germicides (3) | ethylene and propylene oxides, aldehydes |
removal of microbes by mechanical means | degermining |
2 ways of degerming | handwashing and alcohol swabbing before injections |
destruction of microbes and germs on a nonliving tissue | disinfection |
Four examples of disinfectants | soaps, alcohols, aldehydes, phenolics |
What does pasteurization do? | Just prevents more microbes from growing but they are stil present |
Removal of pathogens from objects to meet public health standards | Sanitization |
Examples of sanitation | washing dishes and tableware with scalding water |
killing of all microbes and viruses on or in an object | sterilization |
two examples of sterilization | preparation of culture and canned food |
typically achieved by steam under pressure | sterilization |
How do antimicrobial agents destroy microbes(2) | altering cell wall/membrane and damge to protein/nucleic acid |
what happens if cell wall is damaged | cell loses osmoregulation |
What happens if cell membrane is altered | controls movement of solutes in and out so cellular contents may leak out |
what are the four ideals for a microbial antiagent | inexpensive, fast-acting, stable during storage, harmless top the object it is protecting |
Generally what is the most resistant microbe | Prions |
What is the most susceptible microbe | enveloped viruses |
Which is more susceptible; gram positive or negative | gram positive |
What is the second and third most resistant microbe | bacterial endospores and mycobacteria |
Why is mycobacteria very resistant | Does not have cell wall to be targeted |
classification of germicide where all pathogens including endospores are killed | High-level germicide |
what do intermediate-level germicides do | kill fungal spores, viruses, cysts and pathogenic bacteria |
what type of microbe would a low-level germicide kill (not egs) | Vegetative ones |
What biosafety level would you use for ebola/anthrax | BSL-4 |
Which biosafety level involves handling microbes in a hood | BSL-3 |
what mechanism is used to prevent microbes from leaving a room | negative pressure |
Protective suits would have what type of pressure | positive |
what is the lowest temperature needed to kill all cells in broth | thermal death point |
time needed to sterilize volume of liquid at a set tremp | thermal death time |
Which is more effective; dry or moist heat | Moist heat |
4 moist heat methods for controlling microbes | boiling, autoclaving, pasteurization, ultrahigh-temp sterilization |
Aurtoclaving uses what (2) | pressure and steam |
In sterile indicators, what does a yellow medium mean | Autoclaved objects are not sterile |
What color indicates sterile objects | Red |
ultra sterilized liquids can be store where | room temperature |
how is ultra-temp sterilization done | heated at 140C for 3 secs then rapid cooling |
egs of a dry heat method | incinerator |
what does dry heat do(2) | Denatures protein and oxidizes metabolic and structural chemicals |
How is dry heat requirements different from moist heat(2) | higher temp and longer time period |
What does refidgeration do to microbes | halts its growth not kill it |
What type of freezing is more effective | slow freezing |
Another name for drying | desiccation |
Another name for freeze-drying | lyophilization |
Lyophilization prevents formation | Damaging ice crystals |
Lyophilization is typically used for | long-term preservation of microbial cultures |
Which method uses size | filtration |
Which pore size would be used to filter yeasts and unicellular algae | 3 microliter |
Which pore size would you use if its only largest bacteria | 0.45microliter |
Pore size for largest virus and most bacteria | 0.22 |
How does osmotic pressure prevent microbes | High salt/ sugar concentration inhibits growth |
bacteria/fungi which would survive better in a hypertonic solution | fungi |
Two types of radiation | electromagnetic and particulate radiation |
describe particulate radiation | high-speed subatomic particles freed from their atoms |
describe electromagnetic radiation | energy without mass travelling in waves at the speed of light |
ionizing radiation involves what three things | x-rays, gamma rays, electron beams |
What is the problem with using electron beams radiation to kill microbes | Effective but does not penetrate well |
What is the problem with using gamma rays radiation to kill microbes | Penetrate well but take hours to kill |
What is the problem with using x-rays radiation to kill microbes | requires long time to kill |
what does ionizing radiation do(3) | disrupts h-bonds, oxidize double bonds, create hydroxyl radicles |
nonionizing radiation therapy uses | uv light |
nonionizing is used for (3) | disinfecting air, transparent fluid, surfaces of objects |
What does the uv light cause | pyrimidine dimers |
Does nonionizing radiation form covalent bonds | yes |
example of phenolics not used anymore cuz bacteria has grown resistant to it | triclosan |
of all the phenolics, which has the highest killing rate | phenol |
what limits phenol use | very reactive so can be used on a few things |
phenolics is most effective in the presence of? | organic matter |
2 examples of phenolics | orthocresol and triclosan |
why might one not want to be near phenol | very bad odor |
What does phenolics affect in bacteria | denature their proteins and cell membranes |
what level of disinfectant is alcohol | intermediate |
How do alcohols kill bacteria | by denaturing proteins and disrupting cytoplasmic membranes |
which is more effective; handwashing or sanitizer | hand sanitizer due to alcohol present |
Another intermediate level antimicrobial chemical | halogens |
how do halogens kill microbes | denaturation of proteins |
An example of high level disinfectants and antiseptics | oxidizing agents |
three examples of oxidizing agents | peroxides, ozone, paracetic acid |
what is ozone used for | treatment of drinking water |
what is paracetic acid used for | sterilizing equipments |
function of hydrogen peroxide | disinfect and sterilize surfaces |
what is hydrogen peroxide not useful for and why | open wounds due to catalase activity |
surfactants a what level of what | low level disinfectants |
examples of surfactants(2) | soaps and detergents |
surfactants are good-----agents but not ----- | degerming , antimicrobial |
how do surfactants function | disrupts cellular membranes |
what compounds are surfactants | ammonium(quats) |
quats are made of | hydrophobic tail and ammonium ion |
are heavy metals cidal | no |
what type of agents are heavy metals(2) | bacteriostatic and fungistatic |
%silver nitrate was once used for | blindness prevention caused by N. gonorrhoeae |
compounds containing CHO terminals | aldehydes |
do aldehydes kill or prevent growth | kill |
how do aldehydes kill microbes | crosslinking preventing things from moving in or out of the cell |
2 egs od aldehydes | formalin glutaraldehyde |
how do gaseous agents denature proteins and dna of microbes | by crosslinking functional groups |
examples of things that would use these agents and why | plastics, petri dishes cuz heat cannot be applied to them |
disadvantages of gaseous agents(4) | hazardous, explosive, poisonous, carcinogenic |
2 egs of anti microbial enzymes | lysozyme prionzyme |
how do lysozyme function | digests peptidoglycan |
three types of antimicrobials | antibiotics, semisynthetics, synthetic chemicals |
what are antimicrobials typically used for | treat disease |
3 methods for evaluating disinfectants and antiseptics | phenol coefficient, use-dilution test, in-use test |
first step of use-dilution | metal cylinders are dipped into broth culture of bacteria |
second step of use-dilution | cylinder is immersed into dilution of disinfectant |
third step of use-dilution | cylinders removed, washed and placed into tube of medium |
which test allows to know treatment time and concentration | in-use test |
first step of in-use test | swabs are taken from objects before and after application of disinfectants |
second step of in-use test | swabs inoculated into growth medium and incubated |
third step of inuse test | medium monitored for growth |
define drugs | anything that affects physiology in any manner |
drugs that act against diseases | chemotherapeutic agents |
chemically altered antibiotics | semisythesis |
antimicrobials that are completely synthesized in a lab | synthetics |
naturally occuring antibiotics and chemically altered ones which are more effective | chemically altered |
penicillin is gained from | fungus |
penicillin is effective on what type of bacteria and why | gram positive cuz it works on peptidoglycan |
which bacteria is confused with fungi | streptomyces griseus |
why are antibiotics not used on common cold | cold is caused by viruses not bacteria!!! |
list three qualities of an ideal antimicrobes | selective toxicity, lack of side effects, cidal vs static |
list the three other qualities of ideal microbes | little resistance to development, broad spectrum of activity, favorable pharmokinetics |
meaning of pharmacokinetics | how it is ingested, metabolized and excreted |
meaning of broad spectrum of activity | affect more microbes |
6 mechanisms of action of microbial drugs | inhibtion of attachment/entry, DNA/RNA synthesis, general metabolic pathway, cytoplasmic membrane, protein, cell wall |
why is inhibition of microbial protein synthesis highly selective toxicity | we have different dna than microbes |
which inhibition is common with anti viral | inhibition of DNA/RNA synthesis |
how does penicillin inhibit growth | contains b lactam that prevent cross linking of NAM and NAG of peptidoglycan |
what happens after the inhibition of crosslinking between nam and nag | cell bursts due to osmotic pressure |
two examples of natural beta lactam | penicillin G, cephalothin |
two semisynthetic beta lactams | methicillin and imipenem |
blocks transport of NAG and NAM from cytoplasm | bacitracin |
disrupts mycolic acid formation in mycobacterial | isoniazid and ethambutol |
isoniazid and ethambutol can only work on which type of microbes | acid fast bacteria |
semisynthetic beta lactams are more suitable in what environments | acidic environments |
how do semisynthetic beta lactams affect existing peptidoglycan | Nothing, only prevents new formation |
would it be effective on growing cells, what else | only growing cells |
fungal cells are composed of? | polysaccharides not found in mammals |
what inhibits the enzyme that synthesizes glucan | echinocandins |
part of human that also has 70s ribosomes | mitochondria |
what causes change in the 30s shape. | aminoglycosides like streptomycin |
what does 30s change cause | misreading mRNA |
What blocks docking site of tRNA | tetracycline and some aminoglycosides |
what blocks peptide bond formation | chloramphenicol |