Archaea Flashcards
Through common cellular ancestry, certain molecules are ______ between all living organisms like molecules of transcription.
shared
Archaea share bacterial _____ traits and eukaryotic ___ - ___ machinery and _______ _______.
metabolic traits
DNA RNA machinery and transcriptional factors
Membrane lipids contain ester linkages for archaea (T/F).
False, they are ETHER linkages. Bacteria + eukaryotes have ESTER linkages.
Archaea can form spores and have inclusion bodies (T/F).
False, they can’t form spores but they do have inclusion bodies.
While the cytoskeleton of archaea has bacterial + eukaryotic properties, archaeal protein content is similar to ?
Bacteria
Instead of unbranched fatty acids, archaea have
_________ ______ on their membranes.
Isoprene chains
(T/F) All archaea have lipid monolayers.
False, only some do.
What are the similar features an archaea genome shares with bacteria?
- single, circular DNA
- no nucleus; DNA is within the nucleoid
What are the similar features an archaea genome shares with eukaryotes?
- DNA bound by histones
- DNA replication enzymes look similar
What are the four different structures can the archaeal cell wall be composed of instead of peptidoglycan?
- Pseudomurein
- S-layer
- Methanochondroitin
- Protein sheath
Match the following terms to their definition:
1. Pseudomurein
2. S-layer
3. Methanochondroitin
4. Protein sheath
A. Covers multiple cells forming a chain instead of a single cell.
B. Consists of glycoprotein with a paracrystalline structure of various symmetry: hexagonal, tetragonal, or trimeric. Resists osmotic pressure.
C. Similar to connective tissues in animals
D. Polysaccharide which consists of NAT and NAG. Has b-1,3 glycosidic bonds. All L-stereoisomer amino acids.
Pseudomurein - Polysaccharide consisting of NAT and NAG. Has b-1,3 glycosidic bonds. All L-stereoisomer amino acids.
S-Layer - Consists of glycoprotein with a paracrystalline structure of various symmetry: hexagonal, tetragonal, or
trimeric. Resists osmotic pressure.
Methanochondroitin - Similar to connective tissues in animals
Protein sheath - Covers multiple cells forming a chain instead of a single cell.
What are the differences between peptidoglycan and pseudomurein?
Peptidoglycan:
- b-1,3 bonds
- destroyed by lysozyme + penicillin
- NAG (n-acetyl-glucosamine) & NAM (-muramic acid)
- can have L or D stereoisomers amino acids
- found in bacteria
Psuedomurein:
- b-1,4 bonds
- immune to lysozyme + penicillin
- NAG and NAT (…-talosaminuronic)
- all L stereoisimers amino acids
- found in archaea
(T/F) Psuedomurein is the most common cell wall type in archaea.
False, S-layer is the most common cell wall type.
What is a Hami?
A cell surface structure of archaea. Archaea’s version of fimbrae (surface attachment) which form BIOFILMS.
While bacterial flagella use proton motive force, archaella use ___. Instead of having a whip like motion, they have a ______ motion.
ATP
Rotating
(T/F) All prokaryotes are capable of methanogenesis (methane production).
False, archaea are the only organisms responsible of methane production.
Which molecule do archaea use to use light for ATP production without doing photosynthesis?
Bacteriorhodopsin
(T/F) Bacteriorhodopsin is structurally similar to the rhodopsin found in vertebrate eyes.
True!
Match the following steps regarding on how bacteriorhodopsin produces ATP:
Step 1
Step 2
Step 3
Step 4
Step 5
A.Retinal changes conformation from Trans to Cis
B. Retinal transformation coupled to one proton being pumped outside of the cell
C. ATP synthase uses proton gradient to produce ATP
D. Bacteriorhodopsin absorbs light
E. Retinal is excited by light
Step 1: Bacteriorhodopsin absorbs light
Step 2: Retinal is excited by light
Step 3: Retinal changes conformation from Trans to Cis
Step 4: Retinal transformation coupled to one proton being pumped outside of the cell
Step 5: ATP synthase uses proton gradient to produce ATP
Retinal is a pink molecule.
False, it is purple.
(T/F) Genomes of archaea resemble those of bacteria in gene size and density.
True!
How does the genome structure of archaea resemble eukaryotic genome?
- Certain tRNA genes have introns
- DNA and RNA polymerases and transcription factors are similar to those of
eukaryotes
- Both have TATA box, BRE (b-recognizing element), and formation of pre-initiation complex. - Archaea contain histone homologs
What is a unique feature of the archaeal genome?
Some thermophiles have a reverse gyrase to introduces positive supercoils in DNA, to protect against high temperatures.
Briefly describe the chromatin structure of archaea.
Histones form TETRAMERS to wrap DNA. This allows stacking of units, or superhelix. Histone tails may allow some modifications.
(T/F) Stacking of units (superhelix) is found in all organisms.
False, eukaryotic histone OCTAMERS prevent this. Only done in archaea.
(T/F) 40% of archaea’s genome has no homology to any living organisms.
True!
What is the guanosine analog of archaea?
Archaeosine
Archaeal activators and regulators resemble more that of _______ DNA binding proteins than _____ transcriptional factors.
Bacterial
Eukaryotic
(T/F) Cell division of archaea is well studied.
False! It’s hard to recreate environment in labs.
