HLTH module 3: microbiology Flashcards
what are included in the category of microorganisms?
bacteria, fungi, protozoa, and viruses
bacteria basic characteristics
cell wall present, may have flagella, pili, and fimbriae, have DNA and RNA, reproduce by binary fission, and are treated by antibacterial drugs
virus basic charateristics
have no cell wall, have obligate intracellular parasite, no DNA or RNA, reproduce by host cells, and are treated with antiviral drugs
fungi basic characteristics
eukaryotic (unicellular or multicellular; chains of cells), have a cell wall, have DNA and RNA, reproduce by budding and spores, and are treated with antifungal drugs
protozoa basic characteristics
have no cell wall, sometimes have obligate intracellular parasite, and have DNA and RNA; reproduction and treatment varies
mycoplasma basic characteristics
have no cell wall, have DNA and RNA, reproduce by binary fission, and treatment varies
pathogens
the disease causing microbes that are ‘germs’; most microorganisms are not pathogens
3 types of bacteria groups based on shape
bacilli, spirals, and cocci
bacilli bacteria
are rod shaped; ex. vibrio and pleomorphic
spirals
coiled shape; ex. spirochetes and spirilla
cocci
spherical form
5 types of bacteria prefixes based on arrangements
diplo, sterp(to), staph(ylo), tetrads, and palisade
diplo meaning
bacteria in pairs
strepo(to) meaning
indicates chains
staph(ylo) meaning
irregular, grapelike clusters
tetrads
groups of cells grouped in a packet or square of four cells
palisade
group of cells lying together with the long sides parallel
two types of bacteria cell walls
gram-positive or gram-negative; these differ in the thickness of the peptidoglycan in the wall
what cell wall does penicillin act on?
gram-positive
gram-positive cell membrane
located inside the bacterial wall
gram-negative cell membrane
is located on both sides of the cell wall
external capsule in bacteria
found in some, but not all bacteria; found outside the cell wall in gram-positive and outside the outer membrane in gram-negative; offers additional protection
where does flagella attach to?
the cell wall and may provide motility
pili and fimbriae
tiny hairlike projections found usually on gram-negative bacteria; assist in the attachment of bacteria to issues
where is DNA and RNA found in bacteria?
in the cytoplasm
plasmids
circular DNA fragments that are important in the exchange on genetic information with other bacteria
two types of toxins
exotoxins and endotoxins
exotoxins
usually produced by gram-positive bacteria and diffuse through body fluids; may interfere with nerve conduction
endotoxins
present in the cell wall of gram-negative organisms and are released after the bacteria dies; may cause fever or general weakness
enzymes and bacteria
produced by some bacteria and can damage host cells or tissues; ex. hemolysin which destroys RBCs
endospores
can be formed by bacteria and are a latent form of the bacteria with a coasting highly resistant to heat and other adverse conditions
binary fission
a process of reproduction when the divison of a cell produces two daughter cells identical to the parent
factors affecting bacterial growth
insufficient nutrients and O2, increased metabolic wastes in the area, and changes in pH or temperature
what is a virus?
a very small obligate intracellular parasite that requires a living host for replication
extracellular virus
called a virion; consists of a protein coat and a core of either DNA or RNA
what happens when a virus infects a person?
it attaches to a host cell and the viral genetic material enters the cell and takes over, using the host to synthesize protein, to produce new viral components
how are new viruses released from the host cell?
via lysis or budding of the host cell membrane
why can it be different for immunity to be acquired for viruses?
because they can mutate or change forms slightly during replication
how can viruses cause cancer?
certain intracellular viruses can alter host cell chromosomes, leading to the development of a malignant cells or cancer
what virus is associated with cancer?
human papillomavirus can cause cervical cancer
chlamydiae
related to bacteria but lack enzymes for metabolic processes
two forms of clamydiae
elementary body and reticulate body
elementary body chlamydiae
is infectious; posses a cell wall and can bind to epithelial cells
reticulate body chlamydiae form
is noninfectious but uses the host cell to make ATP and reproduce as an obligate intracellular organism; will eventually change in EBs
what does chlamydiae cause?
pelvic inflammatory disease and sterility in women
rickettsiae
are tiny gram-negative bacteria that live inside a host cell (obligate intracellular parasites)
how are rickettsiae transmitted?
insect vectors (lice or ticks) that cause diseases like typhus fever and Rocky Mountain spotted fever
what does rickettsiae cause?
small hemorrhages and rashes through attacking blood vessel walls
mycoplasma
is an infection that is a common cause of pneumonia; the microbes lack cell walls and therefore are not treated with antimicrobial drugs
fungi infection
results from single-celled yeasts or multicellular molds
hyphae
the long filaments or strands of a fungus that intertwine to form a mass called the mycelium
mycelium
the visible mass formed by hyphae strands
tinea pedis
athlete’s foot caused by fungus invading the superficial layers of the skin
candida
a normal, harmless fungi present on the skin; however, when there are imbalances in the normal flora, it may cause infection in the oral cavity
histoplasma
a fungus that causes infections in the lungs; transmitted by inhaling contaminated dust or soil particles
pneumocystis carinii
is an opportunist that causes pneumonia; has characteristics of fungi and some of protozoa
where do protozoa live?
can live on dead organic matter, independently, or in a living host
3 examples of diseases caused by protozoa
trichomoniasis, malaria, and amebic dysentery
trichomonas vaginalis
causes a STI in the reproductive tracts through attaching to mucous membranes and causing inflammation
what causes malaria?
plasmodium which are part of the sporozoa species of nonmotile protozoa
what occurs in malaria?
microbes enter the RBCs and cause them to eventually rupture, releasing new microbes into the blood, causing acute illness
what is malaria transmitted by?
the female anopheles mosquito
helminths
not microorganisms but often in this category; are parasitic worms that cause infections; are multicellular, and eukaryotic
three stages of helminths
ovum (egg), larva, and adult
how are helminths transmitted?
usually through ingesting contaminated food or water when they are in the ova or larvae stage
where are helminths found?
usually in the intestine, but also the lungs or blood vessels
types of helminths
pinworms, hookworms, tapeworms, and ascaris (giant roundworms)
how are prions transmitted?
transmitted by consumption of contaminated tissues such as muscle or brain or the use of donor tissues
what is a prion?
a protein-like agent that is an abnormal molecule; it induces proteins within the brain to undergo abnormal folding and changes of shape
what diseases can prions cause?
Creutzfeldt-Jakob diseases (and variants), fatal familial insomnia, gerstmann-Sträussler-Scheinker syndrome, and kuru
resident flora
normal population of microorganisms (primarily bacteria) on the skin, in the nasal cavity, and the mouth; different sites host different species
what areas of the body lack a resident flora?
the lungs, brain, bladder, and kidneys
why is a resident flora good?
can help with synthesis of vitamins (ex. K in digestive processes) and can prevent other organisms from starting a colony
antibacterial drugs and the resident flora
can destroy part of the normal flora and allow for an imbalance or growth of other microbes, causing opportunistic infection
