HW (Oct 26)

The metabolic diversity of photosynthetic bacteria stems from different _________. A) light harvesting complexes, electron donors, and organic compounds they produce B) chlorophylls they can have and organic compounds they can produce. C) bacteriochlorophylls and pigments they contain. D) unrelated taxa capable of photosynthesis.

A) light harvesting complexes, electron donors, and organic compounds they produce

As oxygen appeared in the atmosphere, _______ also accumulated, which formed a protective barrier that protects the Earth from _______. A) ozone/ UV radiation B) sulfate/ hydrogen sulfide C) ferrous iron / hydroxylating radicals D) elemental sulfur/ volcanism

A) ozone / UV radiation

Which phylum harbors the MOST functional diversity observed and also has the MOST cultured representatives? A) Proteobacteria B) Actinobacteria C) Bacteroidetes D) Firmicutes

A) Proteobacteria

Whether an organism is classified as a photoheterotroph or a photoautotroph depends on its _________. A) carbon source B) energy sourse C) carbon and energy sources D) oxygen requirements

A) carbon source

The phylogenetic analysis of complex microbial communities often targets small subunit (SSU) ribosomal RNA genes. This is because rRNA is found in all organisms and ______________. A) is highly conserved over evolutionary time B) is easier to extract from samples C) is made by cells only at certain times D) has more genes than mRNA

A) is highly conserved over evolutionary time

The pan genome of a microbial species is constantly changing because of A) substitution and bottleneck events. B) horizontal gene transfer C) bottleneck events. D) substitutions

B) horizontal gene transfer

Dissimilatory sulfide oxidizers use a variety of unique ecological strategies in order to A) position themselves where there is sufficient light for sulfide oxidation. B) position themselves at interfaces where sulfide and oxygen meet C) avoid the toxicity of hydrogen sulfide. D) find organic carbon substrates.

B) position themselves at interfaces where sulfide and oxygen meet

Metagenomics involves the analysis of a microbial community by ___________. A) generating a phylogenetic tree based on all of the versions of a gene in an environment B) sampling and sequencing of the genomes of all of the organisms in an environment C) generating a complete sequence of the genomes of all of the organisms in an environment D) sequencing all of the community RNA in an environment

B) sampling and sequencing all of the genes in an environment

Microbial diversity is thought of in terms of phylogenetic diversity and functional diversity because __________. A) functional diversity only pertains to functions that are not phylogenetic B) similar functional traits are often found in divergent phylogenetic groups C) phylogenetic diversity dictates functional diversity in microbes. D) similar phylogenetic groups almost always have similar functional traits.

B) similar functional traits are often found in divergent phylogenetic groups

What is the difference between a facultative anaerobe, an aerotolerant anaerobe, and an obigate anaerobe? A) Aerotolerant anaerobes do equally well with or without oxygen, but facultative anaerobes do better without oxygen than with it. Obligate anaerobes require oxygen. B) Obligate anaerobes require an oxygenfree environment to survive, but aerotolerant anaerobes grow better in an environment with oxygen than without it. Facultative anaerobes grow equally well in either environment. C) Facultative anaerobes can use oxygen to produce more ATP than without it. Aerotolerant anaerobes are unaffected by oxygen. Obligate anaerobes require an oxygen-free environment to survive. D) Obligate anaerobes require an oxygen-free environment to survive, but aerotolerant anaerobes just grow better in an oxygen-free environment than with oxygen. Facultative anaerobes grow equally well in either environment.

C) Facultative anaerobes can use oxygen to produce more ATP than without it. Aerotolerant anaerobes are unaffected by oxygen. Obligate anaerobes require an oxygen-free environment to survive.

Most methanotrophs are obligate ______ because ________. A) anaerobes / methane is produced in anaerobic environments B) heterotrophs / methane does not provide enough carbon for growth C) aerobes/ the initial state of methane oxidation requires O2 D) fermenters / methane only provides enough energy for fermentation

C) aerobes/ the initial step of methane oxidation requires O2

By isolating total community RNA, using reverse transcriptase to make cDNA copies of it and then sequencing the cDNA, ecologists can ________. A) determine the community genome translation at the moment of sampling B) determine the community metabolic activity at the moment of sampling C) determine the community genomic potential at the moment of sampling D) determine the community genome expression at the moment of sampling

C) determine the community genome potential at the moment of sampling

Functonal traits can be shared between organisms with divergent SSU rRNA sequences because A) horizontal gene transfer can result in the transfer of genes between divergent lineages. B) functional traits may evolve independently in different lineages over time. C) functional traits may evolve independently, be shared through horizontal gene transfer, or be lost in divergent lineages D) functional traits may be lost by different lineages over time.

C) functional traits may evolve independently, be shared through horizontal gene transfer, or be lost in divergent lineages.