Domain Archaea

Question 1

Name 5 phyla of Archea

Answer 1

Crenarcheota 
Euryarchaeota
Korarcheota 
Nanoarcheota 
Thaumarcheota

Question 2

Archea general characteristics

Answer 2

Widest temperature range -2-121 C
Widest range of environments
pH 0-11, high pressure, anaerobic, etc.
Also abundant in mesic environments
Gram +\-
Variable metabolism s

Question 3

How are Archaeal genomes similar to bacteria?

Answer 3

Circular genome
Has operons
Usually smaller

Question 4

How are Archaeal genomes similar to eukaryotes?

Answer 4

Have introns
RNA polymerase has TBP, TFB
Have histones

Question 5

Phylum Crenarcheota

Answer 5

Extremely thermophilic
Many are acidophiles
Most are strict anaerobes
Always have unique lipid Crenarchaeol in their cell membranes
Many are sulfur dependent
Sulfur can be used as an electron acceptor in anaerobic respiration or as an electron source for chemolithotrophs

Question 6

Phylum Thaumarchaeota

Answer 6

all have type 1 toposiomerase, like euks
some live at mesophilic temps
found in the oceans and associated with plant roots
some are symbionts with sponge
 (Cenarachaeum)

Question 7

Phylum Thaumarchaeota,

subgroup Nitrosopumilales

Answer 7

oxidize ammonia, fix CO2
found in oceans
common in soil

Question 8

Phylum Euryarchaeota

5 loose groups

Answer 8

Methanogens
Halobacteria
Thermoplasms
extremely thermophilic S-metabolizers (Thermococcales)
sulfate- reducers

Question 9

Euyarchaeota: Methanogens

Answer 9

5 major orders
thermophiles, mesophiles found in all orders
diverse cell forms (cocci, bacilli, irregular)
strict anaerobes
can be autotrophic
largest group of Archaea
abundant in guts of ruminates, termites, freshwater sediments (rice paddies)
make methane by reducing CO2 (or other one carbon compounds) and oxidizing H

Question 10

Euyarchaeota: Halobacteria

Answer 10

live in high salt concentration, optimum 1.5-5 M NaCl (ocean water is < 1 M)
high pH
Photo taxis- travel toward light
flagellum uses Na+ gradient to rotate
phototrophs use rhodopsin pigments to generate ATP !!
some create organic molecules to raise/maintain internal osmolarity
High GC content in DNA prevents denaturation in high salt concentrations

Question 11

Euyarchaeota: Thermoplasmas

Answer 11

lack cell walls ( no cell wall or S-layer)
chemoorganotroph
optimum growth at 55 C and pH 2
facultative aerobes, grow either aerobically or anaerobically by sulfur respiration

Question 12

Euyarchaeota:Korachaeota

Answer 12

canadite phyla
considered earliest lineage to break off the universal tree of life
no know cultures
known only by rRNA sequences isolated from natural samples
hyperthermophilic

Question 13

Euyarchaeota: Nanoarcheota

Answer 13

candidate phyla
only one know genus
parasites of Crenarcheota
have smallest cell size and genome known

Question 14

What are candidate phyla?

name two

Answer 14

not widely accepted yet because they are unable to be grown in pure culture
Korarcheota and Nanoarcheota

Question 15

Archaea

Answer 15

none are know to be pathogenic to humans

but are symbionts in our guts and others

Question 16

What does optimum growth conditions mean?

Answer 16

optimum growth temperatures are where the microbe grow best in, they can live in other temperatures or environments but not optimally
the optimum temperature is what defines if an organism is a hyperthermophile or other -philes

Question 17

Acidiophiles

Answer 17

low pH < 6

Question 18

Alkaliphiles

Answer 18

high pH >8

Question 19

Psychrophiles

Answer 19

optimum temp is 15 C or lower

Question 20

Psychrotrophes

Answer 20

can grow at low temps but not optimally

Question 21

Pre and sub fixes

Answer 21

• gen: makes
• phile: likes
• taxis: travels

Question 22

Euyarchaeota: Thermoplasmas

subgroups

Answer 22

Thermococcales: record holder for highest temp 106 C

Archaeoglobales: sulfate reducers, have most of the genes to produce methane but can’t