Topic_3_Archaea_students

Archaea "look" like __________.

Bacteria

Genetic analyses show archaea to be very __________.

different

Many archaea live in some of the most __________ places on Earth.

inhospitable

No known __________ human pathogens exist among archaea.

archaeal

The first "archaea" discovered were __________.

methanogens

Comparisons of __________ gene sequences can establish phylogenetic trees.

rRNA

Archaea were originally called __________.

Archaebacteria

The tree of life includes Bacteria, __________, and Eukarya.

Archaea

The size of archaeal cells is usually __________ in diameter.

0.5–5 μm

Archaea can have __________ shapes, similar to bacteria.

rods, cocci, spirals

Some archaea, like Thermoproteus, can be __________ in shape.

rectangular

The shapes of Sulfolobus spp. are often __________.

irregular

In archaeal cytoplasm, microcompartments can be involved in __________ storage.

carbon

Archaea have __________ circular chromosomes.

single

Histones in archaea are different from those in __________.

Eukarya

Archaea possess a __________ membrane.

plasma

The plasma membrane of archaea has a unique __________ construction.

bilayer

Some archaea have __________ linkages in their cell membranes.

ether

Chemically, archaea may have __________ that enhance stability.

monolayers

The cell wall of some archaea is composed of __________.

pseudomurein

The cell surface s-layer in archaea protects against __________.

predation/viruses

Archaea typically have __________ structures to link cells together.

cannulae

The flagellum of archaea grows from the __________ rather than a tip.

base

Thermophiles like Ignicoccus can be found in __________ environments.

high-temperature

The four major phyla of archaea include Euryarchaeota and __________.

Crenarchaeota

Many archaea are __________ and thrive in low pH environments.

acidophiles

Halophiles require a NaCl concentration greater than __________.

1.5M

Extreme halophiles such as Halobacterium thrive in the __________ Sea.

Dead

Halobacterium deals with osmotic shock by maintaining a high intracellular __________ concentration.

K+

The phototrophic bacteriorhodopsin in halophiles harnesses light energy to produce __________.

a proton motive force (PMF)

Euryarchaeota include __________ that produce methane.

methanogens

Methanogens reduce __________ with H2 to produce methane.

CO2

Methanogenic habitats include animal digestive tracts such as __________.

ruminants' rumen

Recent phylogenomic studies propose eukaryotes branched from an __________ lineage.

archaeal

Nanoarchaeum equitans is considered one of the smallest living __________.

organisms

Asgard archaea include groups like Lokiarchaeota which are considered closest relatives to __________.

eukaryotes

Microbial symbiosis may play a role in eukaryogenesis, linking archaea with __________.

eubacteria

TACK is a proposed superphylum for archaea that includes the phylum __________.

Thaumarchaeota

Nanoarchaeota is categorized under the DPANN superphylum, which consists of __________ archaea.

very small

Archaea can exhibit __________ adaptations for survival in extreme environments.

specialized

Archaea are important in biogeochemical cycling of __________ and nitrogen in oceans.

carbon

Archaeal diversity is largely dependent on genomic __________.

sampling

Research continues on the evolutionary relationships between __________ and eukaryotes.

archaea

Pyrococcus furiosus can survive at temperatures around __________ °C.

100

Microbes in deep-sea vents include extremophilic archaea known as __________.

thermophiles

Phyla proposed for archaea remain __________ due to ongoing research.

in flux

Histone proteins in archaea are structural proteins that DNA __________ around.

wraps