Module 3 - Archaea Flashcards
What are some similarities of Archaea and Bacteria?
- Size
- No nucleus (instead have nucleoid)
- Single circular molecule
- Both have similar shape (rods, cones, exc)
- Both have flagella
What are some differences of Archaea and Bacteria?
- Genome sequencing (archaea resemble eukaryotes more than bacteria)
- Unlike Bacteria, Archaea contain histones
- Cell wall composition (peptidoglycan in bacteria vs. pseudomuruein in archaea)
Which cell wall contains N-acetyltalosaminuronic acid?
Archaea (pseudomurein)
Which cell wall contains N-acetylmuramic acid?
Bacteria (peptidogylcan)
Which cell wall contains B-1,3- glycosidic bonds?
Archaea (pseudomurein)
Which cell wall contains B-1,4-glycosidic bonds?
Bacteria (peptidogylcan)
What are the amino acids in pseudomurein?
1-stereoisomers
What are the amino acids in peptidoglycan?
d-stereoisomers
What distinguished Archaea from Bacteria?
- Sequencing analysis of 16S rRNA
- Characterized group of microorganisms capable of producing methane
What are organisms that produce methane called?
Methanogens
What is the function of histones?
To condense/compact the DNA, allowing more DNA to be packaged within a smaller area
Which domain does not contain histones?
Bacteria
Which domain contains a histone tetramer? How many base pairs of DNA?
- Archaea
- 60 bp
Which domain contains a histone octamer? How many base pairs of DNA?
- Eukarya
- 160 bp
What do they presence of histones indicate about the evolutionary history of archaea?
Suggests that histones evolved after the split between bacteria and archaea but before eukarya evolved
What are the eukaryal proteins?
- Tubulin
- Actin
What are the bacterial proteins?
- FtsZ
- MreB
- ParM
Which domain do archaeal cytoskeleton proteins resemble?
Eukaryal actin
What does the plasma membrane in bacteria and eukarya consist of?
Phospholipid bilayer
What does the plasma membrane in archaea consist of?
Isoprenoids
What are hydrocarbon molecules built from 5-carbon isoprene subunits attached to glyercol 1-phosphate (G1P) called?
Isoprenoids
What are the 5-carbon ispoprene subunits attached to?
Glycerol 1-phosphate (G1P)
What is the G1P head group?
Stereoisomer of the molecule found in bacteria and eukarya
Are isoprenoids linked to the glycerol via ether/ester linkages?
Ether
Are phospholipid bilayers linked via ether/ester linkages?
Ester
What is the most commonly used isoprene polymer in many archaea? #-carbon hydrocarbon?
- Phytanyl
- 20-carbon hydrocarbon
What is the alternate used isoprene polymer in archaea? #-carbon hydrocarbon?
- Biphytanyl
- 40-carbon hydrocarbon
With species that contain biphytanyl, what is linked to both ends of the isoprene polymer?
Phosphoglycerol molecule
Is a biphytanyl membrane a phospholipid monolayer/bilayer?
Monolayer
What archaeal species are phospholipid monolayer most commonly associated with?
Archaeal species that live at very high temperatures
Which phospholipid layer is more rigid and offers increased stability at high temperatures?
Monolayer
What are tiny vesicles made from cell membrane material called?
Liposomes
Which phospholipid layer has more stable at high temperatures?
Monolayer
What is the functional role of the outer membrane of the genus Ignicoccus?
Generation of energy across the outer membrane
What is the functional role of the inner membrane of the genus Ignicoccus?
Undergoes constant reorganization
Why is the archaeal cell well less susceptible to antibiotics?
Their cell wall lacks peptidogylcan, which is an excellent target for antibiotics due to their enzymes concerned with synthesis
Which domain contains flagella composed of multiple copies of a single flagellin subunit?
Bacterial flagella
Which domain contains flagella composed of several different subunits?
Archaeal Flagella
Which domain do flagellin monomers add to the base of the growing filament?
Archaeal Flagella
Which domain do flagellin monomers add to the tip of the growing filament?
Bacterial Flagella
Which domain exhibit N-linked glycosylation?
Archaeal Flagellins
Which domain exhibit O-linked glycosylation?
Bacterial Flagellins
Which domain of flagella are 10-14nm
Archaeal
Which domain of flagella are 20-24nm?
Bacterial
What are the two major phyla of archaea?
Euryarchaeota and Crenarchaeota
What are two major groups of Euryarchaeotes?
Methanogens and Halophiles
Where can we find methanogens?
Where CO2, and H are found (necessary substrates)
Are methanogens aerobic or anaerobes?
Anaerobes
Organisms that can survive only in anoxic, or oxygen-free environments are called?
Anaerobes
Most of the Euryarchaeota phylum are called?
Thermophiles or hyperthermophiles
Organisms whose optimal growth temperatures are greater than 55C or 80C, respectively, are called?
Thermophiles; Hyperthermophiles
Organisms that grow in low-pH environments are called?
Acidophiles
Species that grow not only at elevated temperatures, but also at high pressure are referred to as what?
Barophiles
Which phylum of Euryarchaeota has a larger percentage of a-helical regions
Thermophiles
What does an increased a-helical content lead to?
- Increased proportion of arginine and tyrosine
- Strengthened interactions between amino acids
Why is a strengthened interaction between amino acids beneficial to thermophiles?
Allows the protein to maintain its shape at elevated temperatures
What do hyperthermophiles rely on?
Molecular chaperones
Proteins that help fold proteins, or refold denatured proteins, to maintain functionality are called?
Molecular chaperones
Archaeal chaperonins resemble which other domain’ chapteronins?
Eukaryal
What protein complex appears to be abundant and instrumental in hyperthermophilic archaea?
Thermosome
What organisms can only grow with NaCl concentration of at least 1.5M?
Halophiles
Are methanogens or halophiles environments more common?
Methanogens
What challenge must a high-salt environment present?
Osmotic shock
When the ion concentration outside of the cell much higher than the ion concentration inside the cell, this is known as what kind of environment?
Hypertonic
When the ion concentration outside of the cell is less than the ion concentration inside the cell, this is known as what kind of environment?
Hypotonic
What happens to a cell in a hypertonic environment
Shrinks
What happens to a cell in a hypertonic environment
Swells
What well-studied halophile was used to combat the problem of osmotic shock?
Halobacterium salinarum
What does Halobacterium salinarum do to prevent the efflux of water?
Maintains a high intracellular concentration of K+ ions
What members possess a novel means of obtaining additional energy when exposed to low-oxygen conditions?
Halobacterium
What are the two ways that halobacterium acquire energy?
- Phototrophy
- Bacteriorhodopsin
The acquisition of energy from sunlight is called?
Phototrophy
The energy present in sunlight is harvested by another molecule is known as?
Bacteriorhodopsin
What are the adaptations of Crenarchaeaota that allow them to withstand extreme environments?
Plasma membranes containing tetraether lipds, or lipid monolayers
What absorbs the energy present in sunlight in bacteriorhodopsin?
Retinal
What does bacteriorhodopsin function as?
Protein pump; proton motive force