Microorganisms & Medical Microbiology Flashcards
bacteria
- prokaryotes: one-celled organisms w/ no nucleus or membrane-bound organelles
- ribosomes and genetic material are free floating in the cytoplasm
coccus
spherical shaped bacteria the can join together to make:
- diplococci (2 bacteria together)
- strepococci (chains)
- staphylococci (clusters)
bacillus
rod-shaped bacteria that can join together to form diplobacilli, streptobacilli (chains), etc
spirillum
spiral-shaped bacteria
Gram staining
- application of crystal violet and iodine, which create a complex that adheres to the outermost layer of bacteria
- can help determine what antibiotic will be effective
Gram positive
- outermost layer: thick peptidoglycan cell wall
- purple color when stained b/c the bacteria cell wall is dehydrated and traps stain inside
Gram negative
- outermost layer: thin and composed of lipids
- outer membrane is removed, second red dye (safranin) is used
- lighter, pink color
bacteria reproduce:
- asexually
- transformation (DNA from environment)
- transduction (injected by bacteriophage)
- conjugation (DNA transfer from F+)
viruses
- cannot reproduce without a host and are not considered living particles
- genetic material held in a protein capsid
- lack most organelles b/c they do not reproduce or maintain cellular functions
lytic cell
- when a virus infects a cell
- induces cell to reproduce viral DNA instead of its own
- eventually the cell will lyse and release viral DNA into he matrix, can infect a new cell
virulent
-viruses that replicate by the lytic cycle, killing their host cell
lawn
a plated culture
lysogenic cycle
- bacteriophage does not lyse its host, and become integrated into the bacterial genome as a provirus, lying dormant for awhile
- ex: HIV
- environmental cues can cause it to enter lytic cycle
latent infection
virus does not spread as quickly during the lysogenic phase
superinfection
-cells containing proviruses are normally resistant to further infection by similar phages
fungi
- heterotrophic, eukaryotic organisms, most of their organelles mimic human cells
- have cells walls that contain chitin
fungi reproduce:
- sexually: diploid cells, undergo meiosis to create 4 haploid spores
- asexually (fission): one organism divides into 2 daughter cells
spore production
-spores are more resilient to hostile conditions so it occurs when conditions are not favorable
parasites
-organisms that live off of and harm a host that receives no benefit from it
helminths
- parasitic worms (tapeworms, roundworms)
- injested via contaminated food or water
protozoa
-unicellular eukaryotes that have many different features, many cause diseases
nitrogen cycle
- plants produce waste and decompose, releasing ammonia and ammonium ions into the environment
- bacteria then break them down into nitrate and nitrite which can replenish plants or be converted to atmospheric nitrogen
carbon cycle
-microbes contribute to the transfer of carbon molecules thru the cycle via fermentation, catabolism, and anabolism
photosynthesis
-sunlight, water, and CO2 are utilized by chlorophyll cells are utilized to produce sugars, which serve as an energy source