Microbiology Introduction Flashcards
What are prions?
aggregates of proteins that have mutated somehow and cause some trouble in the body
What is an obligate intracellular pathogen?
pathogens that require other cells to multiply
What are the main differences between prokaryotes and eukaryotes?
prokaryotes have fewer organelles, no nucleus, and a cell wall
What are some aspects of bacteria that are targetable by drugs/medications?
peptidoglycan in the cell wall (not present in people), ribosome is slightly smaller than human ribosome
What are some different classes of microbes?
Prions, Viruses, Bacteria, Fungi, Protozoa, Helminths
this list is organized by size.
what are helminths?
“worms” like roundworms, tapeworms. visible to the eye, eukaryotes
What limits bacterial growth?
Nutrients, space, disease
What are different forms of horizontal gene transfer in bacteria?
Phage Transductance - virus will infect bacteria, multiply, leave bacteria, infect new bacteria cells. But! Virus sometimes picks up bacterial DNA instead of viral DNA and will pass the bacterial DNA to the newly infected DNA.
Transformation - passive transfer of DNA by picking
Conjugation - direct transfer of plasmids by contact between bacteria
What type of genetic material do plasmids contain?
Plasmids usually contain extracellular genetic information that you don’t “need” to function but that add to the functions of a cell. Bacteria will have additional virulence factors or antiobiotic resistance or toxins in plasmids.
What are - sense RNA viruses?
Negative sense RNA viruses are viruses which bring along the opposite strand of RNA that they need to create proteins. So they need to bring along reverse transcriptase or an RNA-dependent RNA polymerase to create the complement and create the proteins.
What are + sense RNA viruses?
Positive sense RNA viruses are able to have their proteins translated immediately by the host cell
What organelles do viral genes make? What organelles do viruses take advantage of in the host cell?
viruses only have genetic code for regulating the host cell and making their protein coat and organizing everything into a cluster. they do not have genetic code for making mitochondria, or ribosomes, or plasma membranes. They steal all of this from the host cell.
What type of polymerases are available naturally in human cells?
DNA-dependent DNA polymerase
DNA-dependent RNA polymerase
Are viruses with lipid envelopes more or less stable than viruses with just a protein coat?
Less stable! If the lipid membrane is dessicated (dissolved), they lose their infectious factors and aren’t able to infect host cells anymore. They just become blobs of DNA or RNA in a protein shell. Protein only viruses have the infectious factors on their protein coat which is much more robust.
How does a virus infect a cell?
Viruses recognize target cells by interacting with extracellular receptors. The cell will either be tricked into letting the virus in, the virus will force itself in, or the virus (phage is a virus that infects bacteria) will inject its genetic material. The protein coat dissolves and the viral genome is replicated. The virus eventually takes over the cell, re-assembles its protein coat, and breaks free of the cell
What is reverse transcriptase?
an enzyme used to generate complementary DNA (cDNA) from an RNA template. This DNA is then replicated by the host cell and eventually transcribed/translated into protein
What does - sense RNA viruses need to bring with it into a new host cell?
needs to bring an RNA-dependent RNA polymerase or a reverse transcriptase enzyme! Otherwise it can’t start the multiplication process.
What types of genetic information can be found in viruses?
RNA, DNA. Single Stranded RNA (+ or -) double stranded RNA
What is a naked virus?
A virus with just a protein coat
What are three factors that influence the spread of infectious diseases?
Efficiency of transmission
Duration of infection
Number of people exposed per event.
What are the steps of an infection?
Host encounters pathogen. Pathogen enters host. Pathogen infects host cells. Pathogen multiplies. Pathogen damages host tissues. Someone wins (unless pathogen goes latent)
What are the range of relationships between microbes and hosts
Symbiotic (help one another) neutral (form colonies but don’t cause trouble) latent and active infections, disease
What is a latent infection?
An infection where the virus is not readily multiplying
What is a comunicable disease?
Disease transferred from person to person
What is a zoonoses style infection?
Disease transferred from animal to person
What is a vector borne disease?
Disease transferred from insect to person
What is a nosocomial infection?
Disease transferred from hospital environment to person
What is a fomite infection?
Disease transferred from non-living objects to person (toothbrush)
What are some routes of infection transmission?
All major orifices in the body, direct injection into blood flow (shot or cut or bite), sexual contact.
What are some ways to decrease the duration of infection?
Vaccinate, treat, boost immune system.
What are some ways to decrease the number of exposed/susceptible individuals in a population?
Quarantine, vaccinate
What does obligate mean?
“must have”
What does facultative mean?
“can do either”
What does asymptomatic mean?
no symptoms, as noticed by patient
What does symptomatic mean?
Symptoms noticeable by patient
What does symptomatic mean?
Symptoms noticeable by patient
What are the three phylogenetic domains?
Archaea, Bacteria, Eukaryotes
Compare and contrast basic features of prokaryotes and eukaryotes. What are some implications of these differences for treatment of disease?
Prokaryotes have smaller ribosomes and peptidoglycans in their cell walls. Both of these traits are not seen in eukaryotes and are targetable differences.
Explain the implications for human health and disease of the preponderance and diversity of microbial life on our planet.
There are buckets of things that could go wrong or infect our cells, and there are tons of one-off rare cases because of the sheer number of microbes present on earth. It makes treatment quite tricky.
List the six types of human pathogens and identify the basic characteristics of each:
Prions (proteins) viruses (not living) bacteria (living, small, cell wall, peptidoglycans, gram positive or negative, small ribosomes) fungi (yeasts are unicellular, molds are multicellular), protozoa (unicellular eukaryotes), helminths (worms)
List six steps common to all infectious disease processes
Encounter, Entry, Spread, Multiply, Damage, Outcome
Identify at least five common routes of transmission of infections:
Sexual contact Fluid transfer Contact with bloodstream Entry through bodily orifices Inhalation Ingestion Cuts/wounds
Explain the contributions of efficiency of transmission, duration of infectiousness, and number of exposed contacts to the spread of infectious disease
If you have an efficiently transmitted disease, it will not take much to infect someone once contact is made. Duration of infectiousness allows more people to come into contact with the disease. Number of exposed directly correlates with number of infected.
Describe the effects of time and place on the epidemiology of infection.
There are certain infections much more common in Cuba than in the United States. There are certain bacteria much more prevalent in the fall season than in winter or spring.
List at least four methods for preventing the spread of infection.
Quarantine, Vaccination, Education, Treatment
List at least four methods for preventing the spread of infection.
Quarantine, Vaccination, Education, Treatment
