Deck 20: Archaea

Question 1

Many species in the phylum Crenarchaeota are considered extreme thermophiles or _______,which can grow at temperatures above 100 ^$\circ$ C.

Answer 1

hyperthermophiles

Question 2

Unlike other prokaryotes,archaeons (except Sulfolobus)have two origins of replication.

Answer 2

False

Question 3

Thermophylic members of the phylum ______ can grow in geothermally heated water or soils that contain elemental sulfur.

Answer 3

Crenarchaeota

Question 4

Although Sulfolobus solfataricus grows at pH 2 to 4,it maintains a cytoplasmic pH of about 2,thereby generating a large pH gradient across the plasma membrane.

Question 5

The DNA of some archaeons is stabilized by association with archaeal histone proteins forming particles resembling eukaryotic nucleosomes.

Question 6

Archaeoglobales have been isolated from marine hydrothermal vents.

Question 7

Most Archaea capable of metabolizing glucose do so using a modified _________ -________ pathway.
or

Question 8

Some members of the Archaea lack a cell wall.

Question 9

Many archaeal chromosomes include plasmids.

Question 10

The RNA polymerase enzymes of the Archaea are more similar to eukaryotic enzymes than to bacterial enzymes.

Question 11

Some archaeons are symbionts in animal digestive tracts.

Question 12

Most archaeal mRNAs like those of eukaryotes are spliced.

Question 13

Picrophilus has a pH optimum below 1 and can even grow at or near pH 0.

Question 14

A large number of the genes shared by bacteria and Archaea produce proteins that are involved in _______ _______.

Question 15

Some methanogenic Archaea are capable of fixing nitrogen.

Question 16

Archaeons have been isolated from temperate and cold environments.

Question 17

Glycogen is used as a major carbon and energy reserve by some archaeons.

Question 18

Unlike members of the Bacteria,most archaeons have linear chromosomes with multiple origins of replication.

Question 19

Archaeons are not known to incorporate (fix)carbon dioxide.

Question 20

A peptidoglycan-like polymer found in the cell walls of some Archaea is called __________.

Question 21

The Archaea do not use __________ as a mechanism for reproduction.

A)binary fission
B)budding
C)mitosis
D)fragmentation

Question 22

Which of the following contribute(s)to the differences between the Archaea and the bacteria?

A)Archaea lack muramic acid.
B)Archaea have isopranyl glycerol ethers rather than fatty acid esters in their membrane lipids.
C)Archaea differ from bacteria in their tRNA composition,ribosome structure,and antibiotic sensitivity.
D)All of the choices are correct.

Question 23

Archaeal promoters are most similar to those of _______.

A)viruses
B)bacteria
C)eukaryotes
D)both viruses and bacteria

Question 24

The Archaea generally lack which of the following that are normally found in Gram-negative bacteria?

A)outer membrane
B)a complex peptidoglycan network
C)lipopolysaccharide
D)All of the choices are correct.

Question 25

Diglycerol tetraether lipids

A)are a characteristic feature of thermophilic Archaea.
B)tend to make the membrane less rigid.
C)are found in some bacteria and some Archaea.
D)form typical bilayer membranes in thermophilic Archaea of the genus Thermoplasma.

Question 26

Archaeal cell walls

A)are disrupted by treatment with lysozyme or penicillin.
B)are similar to those of Gram-negative bacteria.
C)lack murein and D-amino acids.
D)include orthomureine.

Question 27

The Crenarchaeota and Euryarchaeota are

A)the two phyla of the Archaea.
B)very closely related based on 16S rRNA comparisons.
C)photosynthetic Archaea.
D)now classified with the bacteria based on genomic sequence analysis.

Question 28

Which of the following genera of the Archaea do not have cell walls?

A)Halobacterium
B)Thermoplasma
C)Thermococcus
D)None of the choices are correct.

Question 29

Because archaeons lack peptidoglycan in their cell walls

A)some have an outer layer of complex polysaccharide.
B)some have an outer layer of protein.
C)they must always be grown in isotonic medium.
D)some have an outer layer of complex polysaccharide and some have an outer layer of protein.

Question 30

If the NaCl concentration drops below 1.5 M the cell walls of Halobacterium disintegrate.

Question 31

Methanogenic Archaea are

A)obligate anaerobes that produce methane.
B)obligate anaerobes that consume methane.
C)obligate aerobes that produce methane.
D)obligate aerobes that consume methane.

Question 32

The primary lipid components of the membranes of extreme thermophiles are ______.

A)sulfolipids
B)cholesterol
C)40 carbon diglycerol tetraethers
D)20 carbon diglycerol diethers

Question 33

Which of the following is/are true of most of the extreme thermophilic Archaea in the phylum of Crenarchaeota?

A)They are sulfur dependent
B)They are acidophiles
C)Their cell walls contain lipoprotein and carbohydrate
D)Unlike most other Archaea,their membrane lipids are similar to those of the bacteria
E)They are sulfur dependent,they are acidophiles,and their cell walls contain lipoprotein and carbohydrate

Question 34

If the NaCl concentration drops below 1.5 M the cell walls of Halobacterium become more rigid.

Question 35

Which of the following is not true about archaeal ribosomes?

A)They are 70S like bacterial ribosomes.
B)They may possess ribosome binding sites homologous to bacterial Shine-Dalgarno sequences.
C)They have similar antibiotic sensitivities to those of bacteria.
D)All of the choices are correct.

Question 36

Archaeal sulfate reducers use elemental sulfur as an electron acceptor.

Question 37

Methanogens can live only in __________ environments.

A)aerobic
B)anaerobic
C)microaerophilic
D)All of the choices are correct.

Question 38

Methanogens may contribute to the greenhouse effect and global warming due to methane production.

Question 39

An organism with a temperature growth optimum near 80 ^$\circ$ C and a pH growth optimum between two and three is usually referred to as a(n)______.

A)halophile
B)thermoacidophile
C)thermophile
D)thermoalkalophile

Question 40

Archaeal membranes contain which of the following lipids?

A)Phospholipids
B)Sulfolipids
C)Glycolipids
D)All of the choices are correct.

Question 41

The photosynthetic membrane of Halobacterium salinarium contains ______.

A)bacteriorhodopsin
B)chlorophyll a and b
C)bacteriochlorophyll
D)archaeochlorophyll

Question 42

Methanogenic Archaea are

A)obligate anaerobes that produce methane.
B)obligate anaerobes that consume methane.
C)obligate aerobes that produce methane.
D)obligate aerobes that consume methane.

Question 43

A modified cell membrane that carries out photosynthesis using bacteriorhodopsin in the absence of chlorophyll is called a _______ membrane.

A)colorless
B)orange
C)purple
D)green

Question 44

Most euryarchaea,except the class Archaeoglobi and the order Archaeoglobales,reduce sulfur during anaerobic respiration by using sulfate as a terminal electron acceptor.

Question 45

Methanogens link ATP synthesis to methanogenesis by _______.

A)substrate-level phosphorylation
B)the reverse TCA cycle
C)the use of bacteriorhodopsin
D)electron transport to generate proton motive force

Question 46

Members of the hyperthermophilic anaerobe lineage are known to reside in marine and terrestrial geothermal habitats.

Question 47

Caldarchaeol lipids are extremely thermostable tetraethers found in many _______.

A)hyperthermophilic archaea
B)hypersalinic archaea
C)psychrophile archaea
D)autotrophic archaea

Question 48

Microbes called the group I archaea or mesophilic Crenarchaeota that were found to oxidize ammonia in marine environments are now placed in the phylum ________.

A)Thaumarchaeota
B)Crenarchaeota II
C)Korarchaeota
D)Euryarchaeota

Question 49

An organism that requires at least 1.5 M NaCl in order to grow is referred to as a(n)______.

A)facultative halophile
B)extreme halophile
C)sodiophile
D)barophile

Question 50

The metabolic feature that defines Thaumarchaeota is _______ _______.
or
or
or

Question 51

Substrates used by methanogens include H₂ and CO₂ as well as short-chain organic compounds such as ______.

A)formate
B)acetate
C)methanol
D)All of the choices are correct.

Question 52

Which of the following do methanogens not use to form methane?

A)Carbon dioxide
B)Formate
C)Acetate
D)Phosphate

Question 53

Archaea in the class _______ are thermoacidophiles that lack cell walls,but strengthen their plasma membranes with large quantities of caldarchaeol,glycoproteins,and lipid-containing polysaccharides.

A)Thermoplasmata
B)Thermococci
C)Pyrococci
D)Archaeoglobus

Question 54

The cell membranes of wall-less archaeons are strengthened by _______.

A)diglycerol ethers
B)glycoprotein or protein layers
C)pseudomurein
D)diglycerol tetraethers

Question 55

The distinct archaeal gene versions of Thaumarchaeota that oxidize ammonia into hydroxyl-amine (NH₂OH)is catalyzed by ______.

A)ammonia monooxygenase (AMO)
B)methanofuran (MFR)
C)methylaspartate pathway (MAP)
D)ammonium dismutase (ADM)

Question 56

Autotrophy has been observed among the ______.

A)methanogens
B)extreme thermophiles
C)cyanobacteria
D)All of the choices are correct.

Question 57

The photosynthetic membrane of Halobacterium salinarium contains ______.

A)bacteriorhodopsin
B)chlorophyll a and b
C)bacteriochlorophyll
D)archaeochlorophyll

Question 58

Which of the following is currently the largest group of cultured Archaea?

A)Extreme halophiles
B)Methanogens
C)Extreme thermophiles
D)Sulfate reducers

Question 59

Defining features of the halobacteria include

A)absolute dependence on temperatures above 65ºC for growth.
B)the production of methane.
C)absolute dependence on a high concentration of NaCl for growth.
D)absolute dependence on low pH conditions for growth.

Question 60

Which of the following is true about the cell-wall-less archaeal genus Thermoplasma?

A)They are spherical at temperatures below 59 ^$\circ$ C.
B)They are filamentous at temperatures at 59 ^$\circ$ C and higher.
C)They are non-motile.
D)They are spherical at temperatures below 59 ^$\circ$ C and they are filamentous at temperatures at 59 ^$\circ$ C and higher.