Microbiology Test 3: Chapter 15 practice questions

The difference between a guild and a niche is a guild describes a group of organisms that carry out similar processes and a niche describes the specific functional role an organism plays within an ecosystem. True False

True

The number of viruses in the ocean is estimated to be 10x greater than the number of microbial cells. True False

True

The terminal restriction fragment length polymorphism method of analyzing microbial community structure yields data on diversity of relative numbers of microbes present. True False

True

The rhizosphere (soils associated with roots) contains more microbes than bulk soils (soil not associated with roots) because of the availability of moisture. energy. carbon. nitrogen.

carbon

Terrestrial deep subsurface ecosystems, hot springs, and hydrothermal vents are three very different habitats, yet they share what important ecosystem characteristic? -High temperatures. -Nutrient poor. -Primary productivity is based on something other than photosynthesis. -All of these choices.

All of these choices.

All of the microorganisms found in deep subsurface ecosystems, hot springs, and hydrothermal vents are chemolithotrophs. True False

False

Given the following ingredients (per liter), what kind of organism would you expect could grow on this media? Agar (15 g), mannitol (15 g), CaCl2.2H2O (0.2 g), K2HPO4 (0.2 g), MgSO4.7H2O (0.2 g). One that does not need a carbon source. One that does not need a nitrogen source. One that does not need an energy source. One that does not need a source of electrons.

One that does not need a nitrogen source

In an ocean ecosystem, the proportion of microorganisms typically decreases with depth, except for archaeal cells which often increase with depth. How can we explain these patterns? -Phytoplankton/algae comprise a significant component of the microbial biomass in the upper layers of the ocean and their metabolism is tied to photosynthesis and the availability of light. -Archael metabolism is based on anaerobic respiration and is not tied to photosynthesis and the availability of light. -Archael metabolism is based on chemolithotrophy and is not tied to photosynthesis and the availability of light. -Both phytoplankton/algae comprise a significant component of the microbial biomass in the upper layers of the ocean and their metabolism is tied to photosynthesis and the availability of light. and archael metabolism is based on chemolithotrophy and is not tied to photosynthesis and the availability of light.

Phytoplankton/algae comprise a significant component of the microbial biomass in the upper layers of the ocean and their metabolism is tied to photosynthesis and the availability of light.

Why does it make sense that sulfide oxidizers are the major primary producers in hydrothermal vent communities? -These communities have large quantities of H2S to use as a source of electrons. -Sulfide oxidizers are one of the few groups of bacteria capable of surviving under the intense pressure found at these depths. -Sulfide oxidizers are one of the few groups of bacteria capable of surviving at the high temperatures found in these communities. -All of these.

These communities have large quantities of H2S to use as a source of electrons.

A body of water that is low in nutrients is classified as oligotrophic. True False

True

It is likely that 1 mm3 of soil harbors far more bacteria than 1 mm3 of ocean water. True False

True

Microbial communities are structured just like terrestrial communities of higher organisms (producer, consumer, etc). True False

True

In ecosystem terms, a guild is a collection of organisms that show some degree of coordination. a group of organisms that carry out similar functions. an association of organisms that are able to co-exist. none of these choices.

a group of organisms that carry out similar functions.

Despite the incredible diversity of niches, ecosystems share all of the following elements except primary producers. decomposers. nutrient cycling. apex predators.

apex predators.

The primary energy generating pathway in the mid water zone of oceans is likely photoautotrophy. chemolithotrophy. chemoheterotrophy. methanotrophy.

chemoheterotrophy

The dominant form of primary productivity in terrestrial, deep subsurface habitats is autophototrophy. autoorganotrophy. chemoheterotrophy. chemolithoautotrophy.

chemolithoautotrophy

The stable isotope method of characterizing microbial communities yields data on community diversity. microbial abundance. community metabolism. all of these choices.

community metabolism.

The philosophy behind the dilution to extinction method of cultivating oligotrophic bacteria is dilution results in very low nutrient concentrations in the media. dilution results in pure cultures. dilution reduces the total number of cells. dilution reduces the competition for nutrients.

dilution results in pure cultures.

Terrestrial hot springs differ from hydrothermal vents in that -hot springs are warmer (60°C) than hydrothermal vents (2°C). -hot springs are acidic while hydrothermal vents are closer to a neutral pH. -hot springs are driven by photosynthesis rather than chemolithotrophy. -both hot springs are warmer (60°C) than hydrothermal vents (2°C) and hot springs are acidic while hydrothermal vents are closer to a neutral pH.

hot springs are driven by photosynthesis rather than chemolithotrophy.

Microbial soil communities are characterized by few species and low abundance. few species and high abundance. many species and low abundance. many species and high abundance.

many species and high abundance.

Microbial growth in bulk soils (those not associated with the roots of plants) is limited because of the lack of moisture available. the pH is not optimal for most enzymes. of the lack of nutrients available. the temperature is not optimal for most enzymes.

of the lack of nutrients available.

A key community role attributed to viruses in ocean systems is -recycling nutrients. -limiting the number of bacterial cells. -exchanging genetic information among microorganisms. -both limiting the number of bacterial cells and exchanging genetic information among microorganisms.

recycling nutrients.

For individual organisms in most ecosystems, energy for metabolism originates from eating other organisms. decomposing organisms. sunlight and carbon dioxide. processing inorganic molecules.

sunlight and carbon dioxide.

The difference between the biological species concept as applied to plants and animals and the operational taxonomic unit concept applied to bacteria is -all members of the same biological species share 100 percent SSU rRNA sequence similarity while all members of the same operational taxonomic unit show only 97 percent similarity. -the biological species concept is based on reproductive isolation while the operational taxonomic unit is based on SSU rRNA sequence similarity. -organisms within a biological species show more variability than organisms within an operational taxonomic unit. -the biological species concept underestimates the number of species while the operational taxonomic unit overestimates the number of taxonomic units.

the biological species concept is based on reproductive isolation while the operational taxonomic unit is based on SSU rRNA sequence similarity.

The composition of microbial communities in the rhizosphere of soils is determined primarily by the amount of moisture available. the amount of energy available. the mixture of carbon compounds available. the mixture of nitrogen compounds available.

the mixture of carbon compounds available.