Willey Test Bank Docx Archaea Ch.20

Prescott's Microbiology, 11e (Willey)

Chapter 20 Archaea

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

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

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

4) Some methanogenic Archaea are capable of fixing nitrogen.

5) Archaeons have been isolated from both temperate and cold environments.

6) Archaeal genomes often include plasmids.

7) Some archaeons are symbionts in animal digestive tracts.

8) Some members of the Archaea lack a cell wall.

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

10) Many species in the phylum Crenarchaeota are considered extreme thermophiles or _________, which can grow at temperatures above 100°C.

11) 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.

12) Thermophilic members of the phylum ________ can grow in geothermally heated water or soils that contain elemental sulfur.

13) Archaeoglobales have been isolated from marine hydrothermal vents.

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

15) Archaeal sulfate reducers use elemental sulfur as an electron acceptor.

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

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

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

19) The Crenarchaeota, Thaumarchaeota, and Euryarchaeota are ________.

A) the three 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

20) 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

21) The primary lipid components of the membranes of extreme thermophiles are ________.

A) sulfolipids

B) cholesterol

C) C40 isoprenoid tetraethers

D) C20 diglycerol diethers

22) Archaeal membranes contain which of the following lipids?

A) Phospholipids

B) Sulfolipids

C) Glycolipids

D) All of the choices are correct.

23) Methanogens can live only in ________ environments.

A) aerobic

B) anaerobic

C) microaerophilic

D) All of the choices are correct.

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.

25) 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.

26) 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.

27) 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

28) An organism with a temperature growth optimum near 80°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

29) 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

30) 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

31) 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

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

A) They are spherical at temperatures below 59°C.

B) They are filamentous at temperatures at 59°C and higher.

C) They are nonmotile.

D) They are spherical at temperatures below 59°C and they are filamentous at temperatures at 59°C and higher.

33) The photosynthetic membrane of Halobacterium salinarium contains ________.

A) bacteriorhodopsin

B) chlorophyll a and b

C) bacteriochlorophyll

D) archaeochlorophyll

34) The cell membranes of wall-less archaeons are strengthened by ________.

A) caldarchaeol

B) lipid-containing polysaccharide

C) glycoproteins

D) All of the choices are correct.

35) 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

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

A) Extreme halophiles

B) Methanogens

C) Extreme thermophiles

D) Sulfate reducers

37) 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

38) 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.

39) Autotrophy has been observed among the ________.

A) methanogens

B) extreme thermophiles

C) cyanobacteria

D) All of the choices are correct.

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

A) Carbon dioxide

B) Formate

C) Acetate

D) Phosphate

41) 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

42) A modified cell membrane that carries out photosynthesis using bacteriorhodopsin in the absence of chlorophyll is called the ________ membrane.

A) colorless

B) orange

C) purple

D) green

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

44) Caldarchaeol lipids are extremely thermostable tetraethers found in many ________.

A) hyperthermophilic archaea

B) hypersalinic archaea

C) psychrophile archaea

D) autotrophic archaea

45) Mesophelic crenarchaeotes (Thaumarchaeota) have been isolated ________.

A) from marine plankton

B) as symbiotes of sea sponges and sea cucumbers

C) from rice paddies and lake sediment

D) as pathogens of whales and giant squid

46) 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

47) The metabolic feature that defines Thaumarchaeota is ________ ________.

48) 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)

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

50) 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

51) Asgard archaea are currently a proposed superphylum rather than being universally accepted because ________.

A) they are known only through DNA sequence fragments; they have not been cultivated in the laboratory

B) they have genes that encode eukaryotic signature proteins such as actin and tubulin

C) they are found in chemically and geographically diverse sites

D) they possess intracellular trafficking proteins even though they lack endoplasmic reticula and Golgi apparati

52) Scientists on a marine expedition collecting metagenomic data discover a novel genome that contains sequences for intracellular trafficking proteins similar to those found associated with the endoplasmic reticulum and Golgi apparatus. They initially hypothesize it is eukaryotic in nature, but discover additional sequences that are distinctly archaeal. The most appropriate classification is ________.

A) the proposed superphylum Asgard

B) the TACK superphylum

C) Euryarchaeota

D) the DPANN superphylum

53) Organisms in phylum Thermarchaeota were first identified as distinct from Crenarchaeota when ________.

A) the unique membrane lipid thermarchaeol was discovered in mesophilic ammonia oxidizers

B) all members of the phylum Crenarchaeota were cultured in the laboratory and found to be different

C) not all members of the phylum could oxidize ammonia

D) whole-genome sequences were processed and compared

54) Members of the phylum Thaumarchaeota produce a membrane lipid that differs from other diglycerol tetraethers found in Proteoarchaeota in that ________.

A) it contains a cyclohexane ring that promotes membrane fluidity at lower temperatures

B) it contains several cyclopentane rings that stiffen the membrane at lower temperatures

C) it contains several cyclohexane rings that stabilize the membrane at high temperatures

D) it contains a single cyclohexane ring within the phosphilipid bilayer that promotes membrane fluidity

55) Studying the partial-genome sequences that result from metagenomic analyses of extreme environments allows researchers to ________.

A) infer the metabolic characteristics of the proposed organisms by analyzing their putative proteins

B) classify them in a specific phylum described in Bergey's Manual

C) finalize the organization of domain Archaea

D) limit the phyla of archaea by sorting them according to their habitats

56) Metabolism of uncultured organisms can be inferred from partial-genome sequence data since ________.

A) comparison of genes and the proteins they encode with genes from known organisms allows researchers to gain insight into the metabolic pathways of proposed organisms

B) the genomes can be spliced into vectors and the proteins made by alternative organisms

C) metabolic pathways do not vary among organisms

D) the organisms may be grown in the laboratory once the analysis is complete, and the metabolic pathways can be studied