McMaster University

BIO 2EE3

CHAPTER 4

1)What is the size range of a typical Archaea cell?

1. 1. 1-5 mm

b. 20-50 mm

c.     1-5 µm

d. 20-50 µm

e. 1-5 mm

2. What is the primary reason that Woese and Fox choose the rRNA molecule to study phylogenetic relationships between organisms?
   1. Ribosomal RNA is very easy to isolate and manipulate
   2. Ribosomal RNA is a very stable molecule
   3. Ribosomal RNA is a molecule found in all living organisms
   4. Ribosomal RNA is abundant in the cell
   5. Ribosomal RNA sequencing was very easy to perform at the same time

3. Which of the following is NOT characteristic of the chromosome found in most archaeal cells?
   1. The chromosome is made of double stranded DNA
   2. The chromosome is found in a structure called the nucleoid
   3. Histones are associated with the chromosome
   4. The chromosome is linear
   5. The chromosome is found in a single copy

4. Which of these is one of the main functions of the cytoplasmic membrane in Archaea?
   1. It gives the cell its characteristic shapes
   2. It acts as a semi permeable barrier to the diffusion of molecules into and out of the cell
   3. It allows attachment to specific receptor molecules on solid surfaces in the environment
   4. It protects against effects or different osmotic pressure
   5. It prevents the diffusion of gases into and out of the cell wall

5. How do the Bacteria and Archaea differ in the way the flagellum proteins are handled?
   1. Archaea proteins are enclosed within a membrane and moved to the outside of the cell
   2. Archaea proteins are transported through the hollow flagellum tube for assembly at the end of the flagellum
   3. Archaea proteins are assembled inside the cell for transport out of the cell
   4. Archaea proteins are added to the growing flagellum shaft at the base
   5. Archaea proteins are excreted to the outside of the cell for self-assembly

6. Many cultured and characterized strains from the phylum Crenarchaeota were isolated from
   1. Dry soil
   2. The ocean
   3. Freshwater lakes
   4. Sea ice
   5. Thermal hot springs

7. Proteins of extreme halophiles contain high amounts of the amino acids            and            to help stabilize them in high salt environments
   1. Glycine, serine
   2. Aspartate, glutamate
   3. Histidine, arginine
   4. Tyrosine, phenylalanine
   5. Arginine, valine

8. Which of these is true about methanogens?
   1. They are anaerobic and produce methane from CO2 reduction
   2. They are aerobic and produce methane from CO2 reduction
   3. They are aerobic and ferment methane
   4. They are anaerobic and ferment methane
   5. They are aerobic and grow on methane

9. Where have halophiles been isolated from?
   1. Hydrothermal vents
   2. Temperate environments
   3. Very cold environments
   4. Both b and c
   5. a, b, and c are correct

10. Some extreme halophiles maintain high internal concentrations of potassium to avoid osmotic shock. What does halophilic bacterial DNA possess that prevents damage from potassium?
    1. A novel nucleotide
    2. A high GC content
    3. The DNA is enclosed inside a protective membrane sac
    4. Their DNA is single stranded instead of double stranded
    5. The DNA is protected by high concentrations of magnesium ions

11. What does Halobacterium salinarum use the protein bacteriorhodopsin for?
    1. Moving water into the cell
    2. Degradation of large polysaccharides
    3. Protection from high salt concentrations
    4. Energy production
    5. Sensing the nutrient environment

12. Besides the methanogens and the halophiles, the phylum Euryarchaeota contains many thermophiles and hyperthermophiles. Most of these are also classified as
    1. Halophiles
    2. Barophiles
    3. Mesophiles
    4. Psychrophiles
    5. Acidophiles

13. What is the name of the scientist who first proposed that Archaea are distinct from Bacteria and should be classified in a separate domain?
    1. Linus Pauling
    2. James Watson
    3. Carl Woese
    4. Barbara McClintock
    5. Stanley Cohen

14. Which of these is correct regarding subunit rRNA?
    1. It serves the same biological function in all organisms
    2. Its sequence changes very slowly over time
    3. It is very stable and easy to work with
    4. It serves the same biological function in all organisms and its sequence changes very slowly over time
    5. These choices are all true

15. The archaeal chromosome is:
    1. Circular and contained within a nuclear membrane
    2. Linear and contains histones
    3. Circular and contains histones
    4. Linear and contained within a nuclear membrane
    5. Circular, contains histones, and contained within a nuclear membrane

16. Several Archaea have a lipid monolayer instead of a lipid bilayer comprising their cytoplasmic membrane. Why could this be an advantage?
    1. This type of structure is permeable to protons
    2. Carbohydrates can easily diffuse across this structure to provide nutrients for the cell
    3. This type of structure offers considerable protection against osmotic pressure
    4. This type of chemical lipid structure is more stable at very high temperatures
    5. Proteins are able to integrate more easily into this type of structure

17. Why might the process of chemotaxis in the archaeon Halobacterium be similar to chemotaxis in Bacteria?
    1. The flagellin protein is almost identical in sequence for both Halobacterium and Bacteria
    2. Flagellum assembly is identical in both Holobacterium and Bacteria
    3. Similar proteins in the chemotaxis signaling pathway are found in both Halobacterium and Bacteria
    4. Both Holobacterium and Bacteria use ATP to turn the flagellum
    5. Genes that encode proteins for flagellum assembly are found in both Halobacterium and Bacteria

18. What is most accepted number of phyla found in the Archaea domain?
    1. Two
    2. Eight
    3. Twelve
    4. Twenty
    5. Forty

19. 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?
    1. More a-helices and the amino acids tyrosine and arginine
    2. More B-sheets and the amino acids glycine and glytamate
    3. More a-helices and the amino acids cysteine and serine
    4. More B-sheets and the amino acids tyrosine and arginine
    5. More B-sheets and the amino acids cysteine and serine

20. You would be able to find methanogens in all of the following environments EXCEPT
    1. A well aerated aquifier
    2. The bottom of a swamp
    3. The rumen of bovines
    4. Sediments from a freshwater lake
    5. The benthic region of the ocean

21. What is the minimum salt requirement of a halophile?
    1. 10 mM
    2. 100 mM
    3. 250 mM
    4. 750 mM
    5. 1.5 M

22. To avoid osmotic shock, the obligate halophile Halobacterium salinarum maintains a high intracellular concentration of which chemical?
    1. Chloride
    2. Sodium
    3. Glycine
    4. Potassium
    5. Glucose

23. What is the specific action of bacteriorhodopsin?
    1. Assembles ADP and phosphate to make ATP
    2. Produces proton motive force using light energy
    3. Facilitates the movement of glucose across the cell membrane
    4. Modification of vitamins for use in metabolism
    5. Binds glucose and other sugars in the cell

24. 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?
    1. Thermoplasma acidophilum
    2. Nanoarchaeum equitans
    3. Phrolobus fumarii
    4. Solfolobus solfataricus
    5. Nitrosopumilus maritimus

25. In which of these are Archaea and Bacteria significantly different?
    1. Membrane lipid structure
    2. Cell size
    3. Chromosome size and organization
    4. Possession of membrane enclosed organelles
    5. Lack of a membrane-enclosed nucleus

26. Some archaeal cells contain pseudopeptidoglycan as their major cell wall component. What is this material composed of?
    1. Lipids and proteins
    2. Sugar polymers that are linked to lipids via an ether bond
    3. Sugar polymers cross-linked via a peptide bridge
    4. Proteins linked together via a glycosidic bond
    5. Lipids cross-linked via a peptide bridge

27. Many of the hyperthermophilic crenarchaeotes that have been grown in culture are also
    1. Acidophiles
    2. Mesophiles
    3. Barophiles
    4. Osmolphiles
    5. Alkalophiles

28. All known hyperthermophiles possess this enzyme to increase the supercoiling of the DNA and help stabilize it at high temperatures
    1. Ligase
    2. Reverse DNA gyrase
    3. Histone
    4. Thermosome
    5. Taq polymerase

29. From which area would you be able to isolate the bacterium Halobacterium?
    1. The Mediterranean Sea
    2. The Indian Ocean
    3. The Great Salt Lake
    4. The Pacific Ocean
    5. Lake Michigan