Chapter 27: Bacteria and Archaea Flashcards
what are prokaryotes
single-celled organisms that make up domain bacteria and archaea
what environments are prokaryotes adapted to
diverse and extreme environments (too acidic, salty, cold, hot)
what is the most abundant organism on Earth
prokaryotes
who were the first organisms to inhibit the Earth
prokaryotes
what is biofilm
one or more prokaryotes grow on diff. surfaces
which is bigger prokaryotic cells or eukaryotic cells
eukaryotic cells
what shapes do prokaryotic cells come in
spheres(cocci), rods(bacilli) and spirals(spirilla)
what do nearly all prokaryotes have
cell wall
what is the function of the cell wall
maintain shape
protect the cell
prevent it from bursting in hypotonic environment
what do most bacterial cell walls contain
peptidoglycan
what is peptidoglycan
network of sugar polymers cross-linked by polypeptides
what is a polypeptide
polymer of proteins
what are eukaryote cell walls made of
cellulose or chitin
cellulose
a polysaccharide sugar that is a fiber and is found in fruit and veggies
what is chitin
polysaccharides and forming the major constituent in the exoskeleton of arthropods and the cell walls of fungi.
what is gram stain
used by scientists to classify bacteria by cell wall composition
what is gram-positive
bacteria have SIMPLE walls have LARGE amounts of peptidoglycan
what is gram-negative
bacteria have less peptidoglycan are more complex with an outer membrane that contains lipopolysaccharides
what are lipopolysaccharides
complex molecule that contains both lipid and polysaccharide parts
what is the peptidoglycan layer important for
cell wall structural integrity( primary component of the wall)
what do antibiotics do to peptidoglycan
target them and damage the bacterial cell walls
what are beta-lactam antibiotics
a broad class of antibiotics that includes penicillin derivatives, cephalosporins
are B-lactam antibotics bacteriocidal?
yes, they inhibit the synthesis of the peptidoglycan layer of bacterial cell walls
what are glycopeptide antibiotics
include VANCOMYCIN, teicoplanin, telavancin, bleomycin, ramoplanin, and decaplanin
what do glycopeptide antibiotics do
used to treat multidrug-resistant Gram-positive pathogens by inhibiting peptidoglycan synthesis of the bacteria cell walls
which gram bacteria is more resistant to antibiotics
gram-negative bacteria
why are gram-negative bacteria more resistant to antibiotics
they have a largely impermeable cell wall and the wall is more complex, so they can’t let a lot of things in
what is the sticky OUTER LAYER of a polysaccharide
capsule or slime layer is present in some prokaryotes
difference between capsule and slime layer
capsule if dense is well defined
slime layer: not well organized
what do both the slime layer can capsule do
enable attachment to the substrate or other individuals, and can shield pathogenic bacteria from the host immune system
when do bacteria form inactive endospores
when water or nutrients are lacking
what can endospores do
withstand extreme conditions and remain viable for centuries
prokaryotes have hairlike appendages called what
fimbriae
what do fimbriae do
allow them to stick to their substrate
what is pili (sex pili)
longer than fimbriae
- pulls cells together and enables the exchange of DNA
what stucture is commonly used by prokaryotes for movement
flagella
where are flagella on prokaryotes
may be scattered
concentrated at one or both ends
what is bacterial flagella composed of
- 42 different proteins
- motor, hook. filament
what do prokary. lack
complex compartmentalization
what do prokary. have instead of complex compartmentalization
specialized membranes that perform metabolic functions (infoldings of the cell membrane)
how many chromosomes do prokay. have
1 circular chromosome
prokaryotes vs. eukaryotes
pro( lack nucleus, one circular chromosome, smaller rings of independently replicating DNA called plasmids)
euk:( multiple linear chromosome, have a nucleus)
what is a plasmid
smaller rings of independtly replicating dna
what are the differences in dna replication, transcription and translation between euk and pro
- pro have less dna and produce fewer proteins( smaller ribosomes
why are the minor differences in DNA replication,
transcription, and translation between euk and pro important
These differences allow antibiotics to kill or inhibit bacterial cell
growth without harming human cells
what are the 3 factors that contribute to high levels of genetic diversity in pro
Rapid reproduction, Mutation, and Genetic recombination
how do prokary. reproduce
asexually, binary fission
what is binary fission
offspring cells are generally identical
what do prokary. rapid adaptation to the environment indicate
highly evolved
what does rapid production of genetic diversity in prok. pop. enable
rapid adaptation by natural selection
what is genetic recombination
DNA from different individuals can be combined by transformation,
transduction, or conjugation
what is horizontal gene transfer
Movement of genes between individual prokaryotes of different species
what is transformation
:prokaryotic cells
incorporate foreign DNA taken up from their
surroundings
what is transduction
:phages (from “bacteriophages,”
viruses that infect bacteria) carry prokaryotic
genes from one host cell to another
what is conjugation
DNA is
transferred between two prokaryotic cells via pilli
what way is dna transfer in bacteria
one way, once cell donates the dna and the other receives it
steps for conjugation in e.coli
A pilus (Pili) of the donor cell attaches to the recipient
– The pilus retracts, pulling the two cells together
– DNA is transferred through a temporary structure called
the “mating bridge”
what required to produce pili
dna piece called the F factor
what does the F factor exist as
plasmid or a segment of DNA within the bacterial chromosome
what are dna donors during conjugation
cells containing the F factor or plasmid function
what are dna recepients during conjugation
Cells without the F factor function as DNA
F factor is transferable during when
conjuagation
what is a recombiant cell
F plasmids dna is transferred
autotroph
use light energy to make their own food
what is a photoautotroph
- light energy
-carbon source: CO2
photosynthetic prokaryotes
chemoautogrouph (autotroph)
inorganic chemicals (NH3)
carbon sournce: CO2 HCO3
unique to certain prokaryptes
photoheterotroph
- light energy
- carbon sournce: organic compounds
- unique to certain AQUATIC AND SALT LOVING PROKARY.
- use light for energy but they don’t just use CO2
chemoheterotroph
- organic comound
carbon compounds: organic compounds - many prokaryotes
characteristics of oxygen metabolism in prokary.
- prok. metabolism varies due to O2
- oligate aerobes
- obligate anerobes
- facultative anerobes
what are oliagate aerobes
require O2 for cellular resipration
what are obligate anerobes
use fermentation
what is facultative anerbobes
Use O2 if it is present or carry out fermantation
what is essential in producing amino acids and nucleic acids
nitrogen
what is nitrogen fixation
prokaryotes convert atmospheric nitrogen N2 to ammonia NH3
what does cooperation among cells of prokaryotes allow
use environmental
resources they could not use as individual cells
what happens in cyanobacterium
photosynthetic
cells and nitrogen-fixing cells called heterocysts (or
heterocytes) exchange metabolic products
what are heterocytes
nitrogen fixing cells
how long do prokaryotes date back to
3.5 billion years ago
what organism is in every environment known to support life
prokaryotes
what reveals prokaryotic diversity
advances in genomics
what led to the division of prokaryotes into 2 domains
genetic anaylsis
what are evolutionary relationships not reflected by
shape, nutritional mode, or motility
what has redefined phylogenetic groups
PCR; polymerase chain reaction
bacteria includes what species
prokaryotic species familiar to most people
what is repersented among bacteria
diverse nutriional types
what are the different bacterias
- proteobacteria
- chlamydias
- spirochetes
- cyanobacteria
- gram positive bacteria
what bacteria is associated with proteobacteria
thiomargarita
what disease is associated with chlamydias
chlamydia
what disease is associated with spirochetes
leptospira
what disease is associated with gram-positive bacteria
steptomyces
proteobacteria
- gram negattive
- photoauto, chemoauto and hetero
what is an example of proteobacteria
sulfur bacterium thiomargarita is an autotroph
examples of heterotrophic probacteria pathogens
gonorrhea, cholera, ulcer
characteristics of chlamydias
- parasitize animal cells
- gram negative walls (lack peptid)
what diseases does chlamydias cause
chla,ydia
common cause of blindness
characteristics of spirochetes
- helical gram negative heterotrophs
- rotating internal filaments
- many are free living others are pathogens
cyanobacteria characteristics
- gram negative photoautotroph
- plant chloroplasts evolved from this bacteria
- solitary fliamentous cyanobacteria are abundant of freshwater and marine phytoplankton
