Prokaryotes Flashcards
what structural components do prokaryotes have?
single celled, contains ribosomes, dna, and has a cell membrane
what is domain archaea?
the oldest taxonomic domain, contains organisms that live in extreme environments
what are methanogens?
prokaryotes that produce methane as a by product, live in anaerobic muds, intestines, and are heterotrophs
what are halophiles?
salt loving prokaryotes, use photosynthetic pigments to capture light energy
what is domain bacteria?
-“true” bacteria, has aerobic and anaerobic forms
-photosynthetic, fermentation, and parasites
what are the 7 key features of domain bacteria?
- morphology
- cell surface & cell wall
- internal organelles
- genome
- reproduction
- nutrition
- oxygen requirements
what is the morphology of domain bacteria?
-single celled
-shape: rods [bacilli], spherical [cocci], spiral [spirilla]
in pairs = diplo_
in lines = strepto_
in clusters = staphylo_
what are the cell membrane contents of domain bacteria?
-contains peptidoglycan - sugars linked together with amino acids
-cell walls may be covered by a capsule: a sticky layer of polysaccharides or proteins
how does peptidoglycan concentration influence bacterial type?
lots of peptido in cell wall = gram +, look purple
not lots of peptido in cell wall = gram -, look pink, also contain an outer membrane on top of the plasma membrane and are more pathogenic
what are bacterial fimbriae ?
“spikes” that allow bacteria to stick to their substrate or other members of a colony
can also attach to host membranes
what are bacterial pili?
appendages to pull cells together or transfer DNA
what do bacterial endospores do?
allows the cell to become highly dormant and “hibernate” to let it remain in harsh conditions for very long periods of time
how do bacterial internal organelles work?
-the bacterial plasma membrane can infold on itself to achieve specific functions
what are the contents of a bacterial genome?
- a single circular, ds chromosome
-very little protein with DNA, may see plasmids
how do bacteria reproduce and how often can they?
-bacteria reproduce through binary fission
-can do so every 1-3 hours
what are the three types of bacterial reproduction?
- transformation
- transduction
- conjugation
what is bacterial transformation?
-donor cell releases DNA into environment
-proteins on recipient surface membrane bind to the DNA molecules and let them into cell
-SS donor DNA is incorporated into host chromosome
what is bacterial transduction?
-bacteriophages may sometimes accidentally [finish latyer]
what is bacterial conjugation for F+ / F- cells?
-F+ cell forms a mating bridge with F- cell and transfers its F+ plasmid into the F- cell
-this creates two F+ bacterial cells
what is bacterial conjugation for Hfr/F- cells?
-Hfr cell forms a mating bridge and incorporates F factor DNA from its circular chromosome into the F- cell
-this creates a recombinant F- bacterium
what do the photo, auto, hetero, and chemo prefixes mean for bacterial nutrition?
photo = obtains energy from light
chemo = obtains energy from chemicals
auto = uses CO2 as energy source from self
hetero = needs organic nutrients as a carbon source
what are the 3 types of oxygen requirements for bacteria?
obligate aerobes = need oxygen to survive
facultative aerobes = fine with or without oxygen but prefer without
obligate anaerobes = oxygen is poisonous
what are 4 ways bacteria contribute to the environment?
- chemical recycling of elements between living/nonliving components of environment
- act as decomposers
- nitrogen fixing = add nitrogen to environment
- can form symbiosis with other organisms for mutual benefit
what are bacterial exotoxins?
-secretions from a bacteria that can cause disease
what are bacterial endotoxins?
toxins released from the cell wall of a bacteria when the bacteria dies
