Unit 2 Review Flashcards
Compare disinfection and antisepsis
disinfection: used on surfaces
antisepsis: on living tissue
Is commercial sterilization an actual form of sterilization? What is it designed to destroy?
commercial sterilization is not a form of sterilization
it is designed to destroy c diff in canned goods
Does a bacteriostatic agent kill microbes?
no, it inhibits their growth
Remember that there are many factors that influence the effectiveness of disinfection. The key factor is the presence or absence of _____________________
organic matter (fecal material, spit, blood)
How does moist heat kill microbes? What is the time, pressure, and temperature in our autoclave? What is the key thing to remember when using an autoclave?
moist heat denatures proteins
in our autoclave, for 15 mins 15 psi at 121 C
when using an autoclave, its important to remember it only works when it comes into direct contact with the organism
How does dry heat sterilization (like flaming a loop) kill microbes?
oxidizes, peels electrons off
What does HEPA stand for?
high efficiency particulate air filter
What are good examples of items that you would use filtration to sterilize?
use filtration anytime you can’t heat something up (vaccines)
What are the 2 key differences between phenol and phenolics? Hint: The 3rd thing is that phenolics don’t smell as bad. What is the best example of a phenolic? In what environment does a phenolic work where most disinfectants will not?
phenolics are used now because they’re more effective, less toxic, and less irritating
example of a phenolic is o phenylphenol (lysol)
phenolics work in the presence of organic matter
What is in most antibacterial soaps?
Triclosan
Where would you find the very effective antiseptic chlorhexidine?
surgical hand scrubs, mouthwashes, shampoos
What does the chlorine in bleach become before it is an effective oxidizing agent?
hypochlorous acid
Is it generally easier to kill a virus with or without a lipid envelope? Gram-positive or gram-negative bacteria?
without the lipid envelope would be easier to kill
gram negative bacteria are stronger than gram positive bacteria
Which antimicrobial did we talk about that is more effective at killing Mycobacterium than most?
phenolics
Define a gene
sequence of DNA that codes for a functional product (most of the time a protein)
difference between genotype and phenotype
genotype is your genetic makeup
phenotype are genes that are being used (observable traits)
DNA complimentary base pairs
A - T
G - C
what direction is dna read in
5’ to 3’
steps of DNA replication
1) RNA primers are laid down so the DNA polymerase has a starting point
2) okazaki fragments of DNA are produced off each RNA primer
3) RNA primers replaced w/ DNA
4) DNA ligase seals gaps and creates 1 continuous strand of DNA
How is the lagging strand different than the leading strand
leading strand is synthesized continuously
lagging strand runs the wrong direction and has to be looped around, has more steps than leading strand
DNA polymerase
DNA replication, reads and builds DNA
RNA polymerase
Transcription, reads DNA and builds RNA
Define transcription
conversion of DNA to mRNA
translation
mRNA to protein
What is removed from eukaryotic RNA before it leaves the nucleus
introns
3 letter sequences for the 1 start codon
AUG
What is degeneracy?
When two codes code for the same amino acid, can tolerate mutation without any problems
what is the most common type of genetic mutation?
base-substitution or point mutation
What is usually the most damaging type of genetic mutation?
frame shift mutation
what is the main way DNA is recombined in transformation
DNA is transferred and recombined as naked DNA in solutions
what is the main way DNA is recombined in conjugation
DNA is transferred and recombined through a pilus on a plasmid
what is the main way DNA is recombined in transduction
DNA is transferred and recombined using a phage or bacteriophage
Define a plasmid
non-chromosomal or extra chromosomal genetic material
can self-replicate
phage
virus that infects bacteria
What is the key feature of genetic vectors like plasmids and phages?
they are self-replicating
Do we make restriction enzymes or find them?
we find them
Why is the PCR so important to the study of genetics? What are the basics of the PCR process?
PCR is polymerase chain reaction
this allows us to amplify DNA
uses rapid temp change & chemicals to rip it apart and build new
Are gene guns used with plant or animal cells (usually)? How about microinjection?
gene guns are used with plant or animal cells
microinjections are used with animal cells
What is cDNA?
complementary DNA
What are the 2 key examples of biotechnology that we talked about in class?
human insulin
human growth hormone
What is the difference between infection and disease?
infection is when you’ve been colonized by a pathogen
disease is a disruption of homeostasis
Are transient microbiota important?
they are important
can lead to immune or neurological responses
Does Dr. O believe that our relationship with our microbiota is primarily an example of commensalism or mutualism? Why?
it is an example of mutualism because both sides win
What are the 2 factors that increase the risk of infections by opportunistic pathogens?
compromised host
wrong location
Define probiotics
living organisms to enhance health
prebiotics
fiber to feed organisms already in your body
What are Koch’s postulates? What are they used for? Why can’t they be used to find the causative agents for all infectious diseases?
they are a way to find the causative agents of a disease
they can’t be used all the time because you might not be able to isolate the organism, you can’t use it if an organism causes multiple diseases, and if one disease is caused by multiple organisms
Define signs
things that can be measured
symptoms
subjective things you have to say something about
communicable
can be spread from one to another
noncommunicable
not spread from one to another
contagious
EASILY spread from one to another
incidence
number of people that get a disease during a given time period
When do we reach herd immunity?
70% - depends on how contagious disease
prevalence
how many people have the disease (old cases + new cases)
the key predisposing factors that increase infectiousdisease risk
anatomical
malnutrition
seasonality (flu season, cold weather)
fatigue
What is a secondary infection? What is the best example?
they are the second infection you get after already getting sick
an example of the flu leading to pneumonia
the basic differences between contact, vehicle, and vector spread of disease
contact spread is when you come into direct contact
vehicle spread are substances like food or water
vector spread is living things carrying diseases
What is a fomite?
inanimate object that spreads disease
Know the 3 types of contact transmission
direct: contact with someone with a disease
indirect: fomites carrying diseases
droplets: someone sneezing and getting their droplets on you
What percent of hospital patients acquire nosocomial infections? Why?
5-15%
compromised hosts, strong microbes, and chain of transmission
What is virulence? What are some factors that can increase virulence?
virulence is how dangerous an organism can be
things that increase virulence are gram negative envelopes around bacteria
What is the most common nosocomial infection? What nosocomial infection has the highest mortality rate?
the most common are infections from catheters (UTIs)
most deadly are pneumonia
What is the most common portal of entry?
mucus membranes of respiratory tract
What is the parenteral route?
anytime you bypass one of your body’s defenses (bite, surgical wound, needles)
What are the 3 adherence factors that you are supposed to remember?
fimbriae
capsule (neatly organised)
bio-films
How do capsules increase virulence?
they evade phagocytosis
What is antigenic variation? What organism is the best example that we talked about?
some organisms can change what they look like on the outside
an example would be the flu
What mineral does a siderophore attach to?
iron
What is a toxoid? An antitoxin?
toxoid - vaccine against toxins (tetanus shot)
antitoxin - antibody therapy to neutralize toxins
What are the key portals of exit?
exits are the same as entry
respiratory and gastrointestinal
Know the ley differences between endotoxins and exotoxins. (gram-positive versus gram-negative, fever or no fever, high or low lethal dose, etc)
endotoxins - produced by gram negatives, FEVER, LD50 is higher, more common
exotoxins - produced by gram positives, LD50 is lower, more toxic
helicase
unwinds DNA
DNA ligase
only needed on lagging strand
seals gaps after fragments of DNA are built
