Intro To Prokaryotes #2 Flashcards
from archaea onwards
what are the 3 broad groups of archaea?
- Methanogens (produce methane)
- Halophiles (salt loving)
- Thermophiles (heat loving)
how do archaeal cell envelopes differ from bacterial envelopes? (4)
- s layer may be only component outside plasma membrane
- some lack a cell wall
- capsules & slime layers rare
- lack peptidoglycan
- s layer may be outside membrane separated by pseudomurein
what feature of the cell wall in archaea make them not susceptible to certain antibiotics (2)
no peptidoglycan so not susceptible to lysozyme, beta-lactam or glycopeptide antibiotics
what are some key features of archaeal membranes? (5)
- have distinct membrane lipids (diff from bacteria & euks)
- branched chain hydrocs (alkyl isoprenoids) bonded to glycerol by ether bonds, not FAs linked by ester bonds
- contain diglycerol tetraethers (not in bacteria or euks)
- some have monolayer structure instead of bilayer (due to diglycerol ethers)
what evidence is there that archaea are in a distinct group and are not eukaryotes or bacteria ?
contain diglycerol tetraethers
have distinctive membrane lipids
(not in bacteria or euks)
how does pseudo murein differ from peptidoglycan (3)
- contains L-aa rather than D-aa;
- has β(1-3) glycosidic bonds and not β(1-4) glycosidic bonds
- contains NAT & NAG not NAM & NAG
what are archaeal chromosomes like?
similar to eubacteria, single closed DNA circle per cell
what do archaeal ribosomes have in common with bacteria?
ribosomes are 70S but shape is variable
what is the protein synthesis of archaea sensitive and resistant to?
- sensitive to anisomycin
- resistant to chloramphenicol and kanamycin (like euks)
aniso affects archaea
chlorine and kites resistant to archaea
what is the EF-2 (elongation factor) in archaea sensitive to?
diphtheria toxin (like euks)
archaea elongates dippy (dipper)
drugs
in what way is archaeal rna polymerase similar to that in eukaryotes?
insensitive to rifampicin and streptolydigin (usually inhibit bacterial transcription)
drugs
what effect does streptolydigin have on prokaryotes?
bacteria: inhibit transcription
archaea: rna polymerase insensitive to streptolydigin
archaea like eukaryotes
drugs
what effect does rifampicin have on prokaryotes?
bacteria: inhibit transcription
archaea: rna polymerase insensitive to rifampicin
archaea like eukaryotes
how is the small subunit rrna in archaea similar to bacterial (1)
is 16S and similar in length to bacteria
which group was archaea more closely related to upon phylogenetic analysis?
eukaryotes
what reasons are there to consider archaea prokaryotic ? (4)
- similar cell sizes to bacteria
- no nuclear membrane & cellular organelles
- possess single, large, circular chromo
- may have plasmids
what is a protoplast ?
plasma membrane & everything within it
what are plasmids? (2)
- extrachromosomal DNA found in bacteria, archaea, some fungi
- usually small, closed circular DNA molecules
what are episomes ?
a type of plasmid that may integrate into chromosome