Deck 4: Archaea

Question 1

Which of these is one of the main functions of the cytoplasmic membrane in Archaea?

A) It protects against effects of differing osmotic pressure
B) It gives the cell its characteristic shapes
C) It acts as a semi permeable barrier to the diffusion of molecules into and out of the cell.
D) It prevents the diffusion of gases into and out of the cell.
E) It allows attachment to specific receptor molecules on solid surfaces in the environment.

Answer 1

C

Question 2

What is the name of the scientist who first proposed that Archaea are distinct from Bacteria and should be classified in a separate domain?

A) Linus Pauling
B) Barbara McClintock
C) Carl Woese
D) Stanley Cohen
E) James Watson

Answer 2

C

Question 3

Which of the following is NOT characteristic of the chromosome found in most archaeal cells?

A) The chromosome is made of double stranded DNA.
B) Histones are associated with the chromosome.
C) The chromosome is found in a structure called the nucleoid.
D) The chromosome is found in a single copy.
E) The chromosome is linear.

Answer 3

E

Question 4

The secondary structure and amino acid composition of proteins from hyperthermophiles differ somewhat from proteins in mesophiles.What would you expect to find in thermophiles?

A) More β-sheets and the amino acids tyrosine and arginine.
B) More α-helices and the amino acids tyrosine and arginine.
C) More β-sheets and the amino acids cysteine and serine.
D) More β-sheets and the amino acids glycine and glutamate.
E) More α-helices and the amino acids cysteine and serine.

Question 5

What are chaperonins ("molecular chaperones")?

A) Channels in the membrane for protein secretion.
B) Proteins used for the secretion of other proteins.
C) Proteins used for the correct folding of other proteins.
D) Proteins involved in the regulation of gene expression at the level of transcription.
E) Sensory proteins found in the cytoplasmic membrane to sense various environmental signals.

Question 6

Many cultured and characterized strains from the phylum Crenarchaeota were isolated from _____ .

A) the ocean
B) freshwater lakes
C) thermal hot springs
D) dry soil
E) sea ice

Question 7

Several Archaea have a lipid monolayer instead of a lipid bilayer comprising their cytoplasmic membrane.Why could this be an advantage?

A) This type of chemical lipid structure is more stable at very high temperatures.
B) Proteins are able to integrate more easily into this type of structure.
C) This type of structure is permeable to protons.
D) Carbohydrates can easily diffuse across this structure to provide nutrients for the cell.
E) This type of structure offers considerable protection against osmotic pressure.

Question 8

Which of these is correct regarding subunit rRNA?

A) It serves the same biological function in all organisms.
B) Its sequence changes very slowly over time.
C) It is very stable and easy to work with.
D) It serves the same biological function in all organisms and its sequence changes very slowly over time.
E) These choices are all true.

Question 9

By consensus of the scientific community,what is the accepted number of phyla found in the Archaea domain?

A) two
B) eight
C) twelve
D) twenty
E) forty

Question 10

Many of the hyperthermophilic crenarchaeotes that have been grown in culture are also _____ .

A) mesophiles
B) acidophiles
C) barophiles
D) osmolphiles
E) alkalophiles

Question 11

What is the primary reason that Woese and Fox choose the rRNA molecule to study phylogenetic relationships between organisms?

A) Ribosomal RNA is abundant in the cell.
B) Ribosomal RNA is a very stable molecule.
C) Ribosomal RNA is a molecule found in all living organisms.
D) Ribosomal RNA sequencing was very easy to perform at the time.
E) Ribosomal RNA is very easy to isolate and manipulate.

Question 12

How does the Archaea cytoplasmic membrane differ- from the Bacteria membrane?

A) The Archaeal membrane contains cholesterol.
B) The Archaeal membrane contains no proteins.
C) The Archaeal membrane is comprised of fatty acids attached to glycerol phosphate by an ester linkage.
D) The Archaeal membrane is comprised of isoprenoids attached to glycerol phosphate by an ether linkage.
E) The Archaeal membrane gives the cell its characteristic shape.

Question 13

Some archaeal cells contain pseudopeptidoglycan as their major cell wall component.What is this material composed of?

A) Lipids and proteins.
B) Sugar polymers cross-linked via a peptide bridge.
C) Sugar polymers that are linked to lipids via an ether bond.
D) Proteins liked together via a glycosidic bond.
E) Lipids cross-linked via a peptide bridge.

Question 14

In which of these aspects do Archaea DIFFER from Eukarya?

A) Histones associated with DNA.
B) The transcription process.
C) The translation process.
D) The replication process.
E) Being diploid in chromosome number.

Question 15

Why might the process of chemotaxis in the archaeon Halobacterium be similar to chemotaxis in Bacteria?

A) Similar proteins in the chemotaxis signaling pathway are found in both Halobacterium and Bacteria.
B) The flagellin protein is almost identical in sequence for both Halobacterium and Bacteria.
C) Genes that encode proteins for flagellum assembly are found in both Halobacterium and Bacteria.
D) Both Halobacterium and Bacteria use ATP to turn the flagellum.
E) Flagellum assemble is identical in both Halobacterium and Bacteria.

Question 16

In which of these are Archaea and Bacteria significantly different?

A) cell size
B) chromosome size and organization
C) lack of a membrane-enclosed nucleus
D) membrane lipid structure
E) possessesion of membrane enclosed organelles

Question 17

How do the Bacteria and Archaea differ in the way the flagellum proteins are handled?

A) Archaea proteins are assembled inside the cell for transport out of the cell.
B) Archaea proteins are excreted to the outside of the cell for self-assembly.
C) Archaea proteins are added to the growing flagellum shaft at the base.
D) Archaea proteins are transported through the hollow flagellum tube for assembly at the end of the flagellum.
E) Archaea proteins are enclosed within a membrane and moved to the outside of the cell.

Question 18

All known hyperthermophiles possess this enzyme to increase the supercoiling of the DNA and help stabilize it at high temperatures.

A) ligase
B) Taq polymerase
C) thermosome
D) reverse DNA gyrase
E) histone

Question 19

What is the size range of a typical Archaea cell?

A))1 - 5 nm
B) 20 - 50 nm
C) 1 - 5 µm
D) 20 - 50 µm
E) 1 - 5 mm

Question 20

The archaeal chromosome is:

A) linear and contained within a nuclear membrane.
B) circular and contained within a nuclear membrane.
C) circular and contains histones.
D) linear and contains histones.
E) circular, contains histones, and contained within a nuclear membrane.

Question 21

From which area would you be able to isolate the bacterium Halobacterium?

A) the Pacific ocean
B) the Indian ocean
C) Lake Michigan
D) the Great Salt Lake
E) the Mediterranean Sea

Question 22

To avoid osmotic shock,the obligate halophile Halobacterium salinarum maintains a high intracellular concentration of which chemical?

A) potassium
B) glucose
C) chloride
D) sodium
E) glycine

Question 23

Evidence clearly shows that Archaea are direct descendants of the earliest life forms.

Question 24

What does Halobacterium salinarum use the protein bacteriorhodopsin for?

A) energy production
B) protection from high salt concentrations
C) moving water into the cell
D) degradation of large polysaccharides
E) sensing nutrient in the environment

Question 25

Some researchers think the crenarchaeotes may comprise about ___ of all bacterial and archaeal cells in moderate and cold environments marine environments.

A) one percent
B) five percent
C) twenty percent
D) fifty percent
E) eighty percent

Question 26

You would be able to find methanogens in all of the following environments EXCEPT:

A) the rumen of bovines.
B) the bottom of a swamp.
C) a well aerated aquifer.
D) sediments from a freshwater lake.
E) the benthic region of the ocean.

Question 27

Some extreme halophiles maintain high internal concentrations of potassium to avoid osmotic shock.What does halophilic bacterial DNA possess that prevents damage from potassium?

A) A novel nucleotide.
B) Their DNA is single stranded instead of double stranded.
C) A high GC content.
D) The DNA is enclosed inside a protective membrane sac.
E) The DNA is protected by high concentrations of magnesium ions.

Question 28

One characterized halophilic archaeal species has an unusual cellular morphology in which cells are flat and square.

Question 29

The Archaea contain a cytoskeleton.

Question 30

What is the specific action of bacteriorhodopsin?

A) Modification of vitamins for use in metabolism.
B) Assembles ADP and phosphate to make ATP.
C) Binds glucose and other sugars in the cell.
D) Facilitates the movement of glucose across the cell membrane.
E) Produces proton motive force using light energy.

Question 31

Which of these is true about methanogens?

A) They are aerobic and grow on methane.
B) They are anaerobic and ferment methane.
C) They are anaerobic and produce methane from CO₂ reduction.
D) They are aerobic and ferment methane.
E) They are aerobic and produce methane from CO₂ reduction.

Question 32

What does Methanobrevibacter smithii use to reduce formate in order to make methane?

A) glucose
B) oxygen
C) nitrogen
D) carbon dioxide
E) hydrogen

Question 33

Which member of the Archaea domain is a parasite of the archaeon Ignicoccus hospitalis and has one of the smallest genomes of all living microbes?

A) Pyrolobus fumarii
B) Thermoplasma acidophilum
C) Nanoarchaeum equitans
D) Nitrosopumilus maritimus
E) Sulfolobus solfataricus

Question 34

What is the minimum salt requirement of a halophile?

A) 10 mM
B) 100 mM
C) 250 mM
D) 750 mM
E) 1.5 M

Question 35

All members of the Archaea domain contain a cell wall.

Question 36

All members of the Archaea live in extreme environments.

Question 37

Where have halophiles been isolated from?

A) hydrothermal vents
B) temperate environments
C) very cold environments
D) both b and c
E) a, b, and c are correct

Question 38

Proteins of extreme halophiles contain high amounts of the amino acids _____ and ____ to help stabilize them in high salt environments.

A) arginine, valine
B) aspartate, glutamate
C) glycine, serine
D) histidine, arginine
E) tyrosine, phenylalanine

Question 39

Which of these is characteristic of a halophile?

A) It grows in a circle on a petri dish.
B) It is extremely small in size.
C) It has an absolute requirement for salt.
D) It requires an acidic environment for growth.
E) It grows only under anaerobic conditions.

Question 40

Besides the methanogens and the halophiles,the phylum Euryarchaeota contains many thermophiles and hyperthermophiles.Most of these are also classified as _____ .

A) halophiles
B) psychrophiles
C) barophiles
D) mesophiles
E) acidophiles

Question 41

How does the chemical structure of archaeal cytoplasmic membrane lipids help these bacteria survive in very hot environments?

Question 42

All known methanogens are found in the domain ___.

Question 43

Why did Woese and Fox use rRNA gene sequences to compare the phylogenetic relatedness between microbes?

Question 44

Most members of the phylum Crenarchaeota that have been isolated and characterized are classified as ___,although environmental DNA samples have shown that these organisms are also present in cold marine environments.

Question 45

What is the function of the protein bacteriorhodopsin in Halobacterium salinarum?

Question 46

All members of the phylum Crenarchaeota are hyperthermophiles.

Question 47

Woese and Fox were able to show that the Archaea were not related to either Bacteria or Archaea and should constitute a separate domain of life using _____ ______ sequences

Question 48

Halobacterium salinarum possess the red-colored protein ___ that absorbs light energy to pump protons across the membrane to create a proton motive force.

Question 49

Archaeal cells get most of their protection against osmotic pressure differences from their _____.

Question 50

Members of the archaeal phylum Euryarchaeota are similar in their rRNA gene sequence but differ greatly in their metabolic characteristics.