Exam 16: Diversity of Archaea

Nitrifying Archaea such as Nitrosopumilus maritimus use ________ as a sole carbon source and are capable of obtaining sufficient energy by aerobically oxidizing ________.

Why does Archaeoglobus represent a metabolically transitional type of organism that bridges the energy-generating processes of H₂S production and methanogenesis?

Speculate on the possibility of life on other planets.Use representatives of the hyperthermophilic Archaea and hydrogen chemolithotrophs as a guide to this discussion.

Although the domain Archaea contains many acidophilic organisms,there are still many others within the domain that grow well in environments with a neutral pH.

Halophilic Archaea are the only inhabitants of highly saline environments.

Which of the following is TRUE about the crenarchael genera Sulfolobus?

Which archaeal phylum contains primarily extreme halophiles and methanogens?

Describe two mechanisms that Archaea use to avoid their DNA melting at temperatures above 100°C.

Archaeoglobus is a true sulfate reducer that forms a phylogenetically distinct lineage within the Euryarchaeota.

Many hyperthermophiles are chemolithoautotrophs.

Where is the thermosome found,and what is its apparent role?

Why does Halobacterium pump large quantities of K⁺ cations into its cytoplasm from the environment? What would happen if Halobacterium did not do this?

A chemoorganotroph growing optimally at 55°C and pH 2 in complex media would most likely be a member of the genus

Some crenarchaeotes have growth optima above the boiling point of water (at atmospheric pressure).

The taxonomy of the methanogens is based on

Some members of the Thermoplasmatales can grow at pH levels below

The light-stimulated proton pump of Halobacterium salinarum indirectly functions to pump sodium out of the cell by the activity of a Na⁺/H⁺ antiport system.

Thus far,only Archaea have been found in the salt lakes,while Bacteria and Eukarya are noticeably absent.

________ is a strict anaerobe with an optimum growth temperature of 105°C that grows chemolithotrophically on H₂ with S⁰ as an electron receptor or chemoorganotrophically on complex mixtures of organic compounds.

Despite GC pairs having an additional hydrogen bond than AT pairs,hyperthermophilic Archaea generally have a lower GC ratio in their genomes when compared to other heat-sensitive prokaryotes.