intro to microbiology Flashcards
what is microbiology
the study of microbes/microorganisms that are usually too small to be seen with the unaided eye
what types of organisms are studies in microbiology
bacteria, archaea, fungi, protozoa, algae, viruses
which organisms that we study are acellular
viruses, viroids, satellites, prions
which organisms that we study are cellular
bacteria, archaea, fungi, protists
what are viruses composed of
protein and nucleic acid
what are viroids composed of
RNA
what are satellites composed of
nucleic acid enclosed in a protein shell
what are prions composed of
protein
how big is the average microbe
1mm or less in diameter
what is a microbe called when it’s bigger than 1mm (ie visible without a microscope)
macroscopic microbe
what are the characteristics of macroscopic microbes
they’re multicellular but lack differentiated tissues
list the (outdated) five kingdoms
monera, protista, fungi, anamalia, and plantae
why is the kingdom system no longer accepted
prokaryotes are too diverse to group them together in a single kingdom (monera)
describe the universal phylogenetic tree
separated into three groups: bacteria, archaea, and eukarya
T or F: most members of the bacteria domain are single-celled
true
T or F: most members of the bacteria domain have cell walls
true
what are the cell walls of bacteria made up of
peptidoglycan
do bacteria cause disease? explain their role in the human body
most bacteria do not cause disease, but instead they’re major inhabitants of our bodies, forming the human microbiome
what are some roles of bacteria in the human body
they contribute to the development of the immune system + they help us digest food and produce vitamins
how are members of the archaea domain distinguished from bacteria
they have distinct rRNA sequences, cell walls, and membrane lipids
T or F: some archaea can generate natural gas (methane)
true
what types of environments are archaea usually found in
extreme environments: high temp or high salt concentrations
what does the eukarya domain encompass
plants, animals, protists, fungi
describe protists
unicellular but larger than most bacteria and archaea
describe fungi (ie their number of cells)
can be unicellular (yeasts) or multicellular (molds and mushrooms)
how many cells do viruses have
viruses are acellular
what are viruses/how do they multiply
entities that must invade a host cell to multiply
how do satellites complete their life cycles
they must coinfect a host cell with a virus (called a helper virus)
what do prions do
they’re responsible for causing neurological diseases
describe the binomial naming system
Genus + specific epithet
- genus = capitalized
- name is underlined or italicized
- names are latinized
what is the average bacterial size
1 um by 2-6 um
what are the two most common bacterial shapes
cocci and rods
what shape are cocci
spherical
what are diplococci
pairs of cocci (ie two spheres together)
when do we get long chains of cocci
when cells adhere after repeated divisions
in which genera of bacteria do we see long chains of cocci
streptococcus, enterococcus, and lactococcus
(note: these should be underlined or italicized)
in which genus do we see grapelike clusters
staphylococcus (italicized)
what is another name for rods
bacilli
which bacteria is comma-shaped
vibrios
which bacteria are rigid and spiral-shaped
spirilla
define what it means for a bacteria to be pleomorphic
it’s variable in shape and lacks a single form
what are hyphae
long filaments that some bacteria can form
what can hyphae form
a network called a mycelium
define mycelium
a network made up of hyphae, which are long filaments that bacteria can form
what does being filamentous allow for bacterial cells
allows for some degree of differentiation among cells in the filament
where is the cell envelope on a cell
surrounds the cell + is several layers
what does the cell envelope include
PM, cell wall, and capsule or slime layer
what is the innermost layer of the envelope
PM
what is the role of the PM
surrounds the cytoplasm
what layer covers the PM
cell wall
what layer surrounds the cell wall
capsule or slime layer
describe the interior of a bacterial cell
simple, since there are no membrane-bound organelles
where is the genetic material of a bacterial cell located
in the nucleoid
T or F: there is a membrane around the nucleoid of a bacterial cell
false! the nucleoid has no membrane, so it is not separated from the surrounding cytoplasm
what two things can be found in the cytoplasm of a bacterial cell
ribosomes and inclusions
what can be found protruding from the surface of a bacterial cell
pili
what is the role of pili
aid in attachment to other surfaces
what is the role of flagella
locomotion
where are flagella on a bacterial cell
they’re positioned like a tail on one end of the bacterium
