Topic 3 - Archaea - Clickers Flashcards
Both bacteria and archaea have (or can have)… (choose ALL that apply)
a) nucleoids
b) cytoskeletons
c) gas vesicles
d) circular chromosomes
e) nucleosomes
a) nucleoids
Explanation: Both bacteria and archaea have nucleoids as they lack membrane-bound nuclei.
b) cytoskeletons
Explanation: Both domains possess cytoskeletal elements for structural support and division.
c) gas vesicles
Explanation: Gas vesicles are present in some bacteria and archaea for buoyancy.
d) circular chromosomes
Explanation: Both typically have circular chromosomes.
e) nucleosomes
Explanation: Only eukaryotes have nucleosomes; bacteria and archaea lack histone-bound DNA.
Like bacteria, the cytoplasmic membrane of archaea (choose the FALSE option):
a) is semipermeable.
b) contains integral proteins.
c) can exist as a monolayer.
d) is composed of lipids.
c) can exist as a monolayer.
Explanation: Archaeal membranes can form monolayers due to their unique ether-linked lipids, unlike bacterial membranes.
If you were a microorganism about to take a vacation at a hydrothermal vent (hot!), which adaptation would you choose from the list below?
a) Unsaturated membranes
b) Biphytanyl chains
c) Ester linkages
d) Bilayer membrane
b) Biphytanyl chains
Explanation: Biphytanyl chains provide stability to membranes at high temperatures, a feature of archaea in hydrothermal vents.
A characteristic that is UNIQUE to the domain Archaea is…
a) the ability to survive in extreme environments, like thermal springs.
b) DNA polymerase that is associated with the nucleoid.
c) a cell membrane constructed from isoprene units.
d) a single, circular chromosome.
e) the presence of L-amino acids in the cell wall.
c) a cell membrane constructed from isoprene units
Explanation: Archaea have membranes made of isoprene chains linked to glycerol by ether bonds, unlike bacteria.
Which of these statements is TRUE?
a) The archaella of archaea and the flagella of bacteria are both powered by ATP.
b) Some archaea have chloroplasts.
c) All known methanogens are in the Crenarchaeota.
d) Archaella grow from the base.
d) Archaella grow from the base
Explanation: Unlike bacterial flagella, archaella assemble at their base, a unique feature of archaeal motility structures.
If you were a thermophilic archaeon at a hydrothermal vent, which adaptation would you NOT choose from the list below?
a) reverse DNA gyrase
b) tetraether lipids
c) more β-sheets in proteins
d) presence of chaperone protein complexes
e) more salt bridge interactions
c) more β-sheets in proteins
Explanation: β-sheets are not a primary adaptation for thermophilic archaea; instead, proteins in these organisms often feature more salt bridges and chaperones to stabilize their structures at high temperatures.
One characteristic that archaea and bacteria share is…
a) glycerol-1-phosphate head groups
b) lipid membrane
c) ether linkages
d) pseudomurein
e) isoprenes
b) lipid membrane
Explanation: Both archaea and bacteria have lipid membranes, although the chemical composition and linkages differ significantly.
Which of the following is a structural adaptation for life at high temperature?
a) Saturated membranes
b) Ester linkages
c) High GC content
d) Fatty acids
e) Lipid bilayers
a) Saturated membranes
Explanation: Saturated membranes help maintain stability and reduce fluidity at high temperatures, a critical adaptation for thermophiles.
Where would you most expect to find methanogens?
a) Where you might find sunlight
b) Where you might find aerobes
c) Where you might find fermenters
d) Where you might find magnetosomes
e) Where you might find Cyanobacteria
c) Where you might find fermenters
Explanation: Methanogens are often found in anaerobic environments where fermentative organisms produce substrates like CO2 and H2.
The cytoplasmic membrane of archaea… (choose the FALSE option):
a) possesses D-amino acids.
b) can exist as a monolayer.
c) is semipermeable.
d) is composed of lipids.
e) contains integral proteins.
a) possesses D-amino acids.
Explanation: Archaea do not possess D-amino acids in their membranes; this characteristic is found in bacterial cell wall peptidoglycan.
Pick the INCORRECT match:
a) Stalk - Caulobacter
b) Cyanobacteria - oxygenic photosynthesis
c) Halobacterium - Euryarchaeota
d) Crenarchaeota - extremophiles
e) Endospores - Gram negative bacteria
e) Endospores - Gram negative bacteria
Explanation: Endospores are a feature of certain Gram-positive bacteria, such as Bacillus and Clostridium species.
Pick the INCORRECT match:
a) Heimdallarchaeia - eukaryotes
b) Euryarchaeota - salt
c) Crenarchaeota - methane
d) Thaumarchaeota - ammonia
e) DPANN - small
c) Crenarchaeota - methane
Explanation: Methane production is a characteristic of Euryarchaeota, not Crenarchaeota.
There is wide variability in physiology and morphology both between and within the major groups of the Archaea. In light of this variability, on what basis are species assigned to each phylum within the domain?
a) energy sources
b) temperature optima
c) nucleic acid sequence similarity
d) structure of the cytoplasmic membrane
c) nucleic acid sequence similarity
Explanation: Species within the domain Archaea are classified based on nucleic acid sequence similarity due to their genetic diversity.
Halophiles thrive in environments of high ______ concentration.
a) acid
b) xbox
c) salt
d) alkali
e) sugar
c) salt
Explanation: Halophiles are adapted to thrive in environments with high salt concentrations, such as salt flats and saline lakes.
Where would you LEAST expect to find methanogens?
a) Rumen
b) Ocean sediment
c) Hydrothermal vents
d) Termite guts
e) Human skin
e) Human skin
Explanation: Methanogens are typically found in anaerobic environments, such as animal guts and sediments, but not on human skin, which is an aerobic environment.
Pick the CORRECT match.
a) DPANN - ammonia
b) Crenarchaeota - methane
c) Thorarchaeota - ammonia
d) Euryarchaeota - eukaryotes
e) Thaumarchaeota - ammonia
e) Thaumarchaeota - ammonia
Explanation: Thaumarchaeota are a phylum of Archaea known to oxidize ammonia as a primary metabolic process.
Eukaryotic microorganisms spatially separate transcription and translation (nucleus). Bacteria and archaea…
a) carry out transcription in the nucleoid and translation in the cytoplasm.
b) chaperones protect RNA until transcription complete, then shuttle RNA to ribosomes.
c) no idea, never thought about this.
d) couple transcription and translation. Polymerase and ribosomes work on the same templates at the same time.
d) couple transcription and translation. Polymerase and ribosomes work on the same templates at the same time.
Explanation: In bacteria and archaea, transcription and translation are coupled, allowing simultaneous processes in the cytoplasm.
How do bacteria photosynthesize without chloroplast membrane systems that provide barriers to establish a proton motive force (PMF)?
a) Bacteria use a non-membrane system to generate a PMF.
b) Bacterial forms of chlorophyll do not require a PMF to complete photosynthesis.
c) Bacteria use the cytoplasmic membrane as the necessary barrier.
d) Bacteria are not capable of photosynthesis.
c) Bacteria use the cytoplasmic membrane as the necessary barrier.
Explanation: Photosynthetic bacteria use the cytoplasmic membrane to establish the proton motive force needed for energy generation.
Bacterial cell walls are composed of _________, algal cell walls are composed of _________, and fungal cell walls are usually composed of _________.
a) peptidoglycan; cellulose; chitin.
b) cellulose; chitin; peptidoglycan.
c) chitin; peptidoglycan; cellulose.
d) cellulose; peptidoglycan; chitin.
a) peptidoglycan; cellulose; chitin.
Explanation: Bacterial cell walls are made of peptidoglycan, algal cell walls of cellulose, and fungal cell walls of chitin.
You have isolated a new microbial halophile from the Dead Sea and it has histone proteins for its DNA. What would you predict for its cell wall?
a) Chitin: Found in fungal cell walls, chitin is composed of N-acetylglucosamine (NAG) linked by β-(1,4)-glycosidic bonds. This structure is characteristic of fungi, including microorganisms like Saccharomyces cerevisiae, which are used in the production of bread, beer, and wine.
b) Pseudomurein: Found in the cell walls of some archaea, pseudomurein consists of N-acetyltalosaminuronic acid (NAT) and N-acetylglucosamine (NAG) linked by β-(1,3)-glycosidic bonds. This structure is unique to archaea and is not found in bacteria or fungi.
c) Simplified peptidoglycan-like structure: Found in certain archaeal species, this structure has similarities to bacterial peptidoglycan but uses alternative arrangements of structural components, making it distinct from both peptidoglycan and pseudomurein.
d) Polysaccharides and proteins: Found in the cell walls of halophilic archaea, this structure does not include peptidoglycan or pseudomurein. It is adapted for survival in highly saline environments, characteristic of halophilic archaeal species.
d) Polysaccharides and proteins
Explanation: Halophilic archaea, such as those found in the Dead Sea, do not have peptidoglycan or pseudomurein in their cell walls. Instead, they possess cell walls composed of polysaccharides and proteins that are highly stable in extreme saline environments. These components help maintain cell integrity and functionality in high-salt conditions
Where would you classify Nanoarchaeum?
a) DPANN
b) TACK
c) Euryarchaeota
d) Korarchaeota
e) Asgard
a) DPANN
Explanation: Nanoarchaeum is a member of the DPANN superphylum, which includes diverse and often symbiotic or parasitic archaea with small genomes.
Which of the following statements about archaea is true?
a) Archaea share a similar plasma membrane to bacteria
b) Archaea have multiple organelles that are found in all species
c) Archaea share a similar RNA polymerase to one of those in eukaryotes
d) All archaea have pseudomurein
c) Archaea share a similar RNA polymerase to one of those in eukaryotes
Explanation: Archaea have RNA polymerases that are structurally and functionally similar to those found in eukaryotes, highlighting their evolutionary relationship.
Features of modern-day Asgard archaea that support them being the closest relatives to eukaryotes? (choose FALSE option)
a) Ubiquitin
b) Membrane remodeling
c) Endocytosis
d) Mitochondria
e) Cytoskeleton
d) Mitochondria
Explanation: Asgard archaea share features such as ubiquitin, membrane remodeling, and cytoskeletal elements with eukaryotes, but they lack mitochondria, which are a defining feature of eukaryotic cells.
