Ch 31 Flashcards
Ionized ammonia applied to soil is effectively retained because clays in the soil have a charge that is ____
A. positive.
B. negative.
C. uncharged.
D. none of these
negative
An average gram of forest soil contains about
A. 2 109 bacteria and archaea.
B. 4 107 bacteria and archaea.
C. 4 107 protists.
D. 2 109 fungi.
4 x 10^7 bacteria and archaea.
A unique feature of terrestrial filamentous fungi not found in aquatic fungi is
A. oxygen-impermeable structures including sclerotia and hyphal cords.
B. formation of flagellated spores that aid in spore dispersal.
C. mitochondria with highly invaginated cristae that permit more rapid diffusion of oxygen for oxidative phosphorylation.
D. all of the choices
oxygen-impermeable structures including sclerotia and hyphal cords
Geosmin, which contributes to the characteristic earthy odor of soils, is produced primarily by the genus
A. Streptomyces.
B. Paramecium.
C. Caenorhabditis.
D. Armillaria.
Streptomyces
One of the more important genera of gram-positive aerobic actinomycetes found in soils is
A. Streptomyces.
B. Bdellovibrio.
C. Acinetobacter.
D. Pseudomonas.
Streptomyces
Most organic matter found in soils results from primary producers such as
A. cyanobacteria.
B. vascular plants.
C. photosynthetic protists.
D. none of the choices
Vascular plants
Mycorrhizae are formed by the association of plants with
A. algae.
B. actinomycetes.
C. cyanobacteria.
D. fungi.
Fungi
The ____________ mycorrhizae are the most common type of mycorrhizae.
A. arbuscular
B. ericaceous
C. orchidaceous
D. monotropoid
arbuscular
In the process of forming a root nodule, species of Rhizobium differentiate to form a type of cell called a
A. lymph node.
B. bacteroid.
C. nucleoid.
D. vesicle.
bacteroid
A major organism involved in associative nitrogen fixation in the rhizosphere of many plants is
A. Azospirillum.
B. Rhizobium.
C. Frankia.
D. Pseudomonas.
Azospirillum
Ti plasmids in the species Agrobacterium tumefaciens
A. is required for nitrogen fixation.
B. causes the formation of tumors.
C. carries the genes needed for root nodule development.
D. carries the genes needed for formation of bacteroids.
causes the formation of tumors.
In a mycorrhizal relationship, the fungal component can assist in providing phosphorus and water to the plant. The plant in turn provides the fungus with
A. metal cofactors.
B. organic carbon.
C. nitrogen.
D. carbon dioxide.
Organic carbon
Actinorrhizae can benefit the plant by providing it with the products of
A. nitrification.
B. denitrification.
C. nitrogen fixation.
D. sulfate reduction.
nitrogen fixation
Rhizobium and Bradyrhizobium are significant contributors to which process when engaged in a symbiotic relationship with leguminous plants?
A. nitrification
B. nitrogen fixation
C. denitrification
D. sulfate reduction
nitrogen fixation
A common resident of the rhizosphere that can enhance plant growth is
A. Arthrobacter.
B. Erwinia.
C. Sphingomonas.
D. Pseudomonas.
Pseudomonas
The formation of an infection thread is an important initial part of microbial interactions with plants in the process of
A. nitrification.
B. nitrogen fixation.
C. denitrification.
D. sulfate reduction.
nitrogen fixation
When rhizobia approach a plant root, the plant initially responds by
A. an oxidative burst.
B. an increase in exudate.
C. releasing flavonoid inducer molecules.
D. producing leghemoglobin.
an oxidative burst
The region of soil in the immediate vicinity of the roots of plants is called
A. plant crust.
B. rhizosphere.
C. phyllosphere.
D. microbivory.
rhizosphere
Which of the following statements is correct?
A. All plants maintain a mycorrhizal relationship.
B. Most plants maintain a mycorrhizal relationship.
C. Some plants maintain a mycorrhizal relationship.
D. Only a few plants maintain a mycorrhizal relationship.
Most plants maintain a mycorrhizal relationship.
One of the most common bacterial genera cultured from plant leaves is
A. Nocardia.
B. Cellulomonas.
C. Sphingomonas.
D. Arthrobacter.
Sphingomonas
The stems and leaves of plants, called the ___________, provide a habitat for a wide variety of microorganisms.
A. plant crust
B. rhizosphere
C. phyllosphere
D. microbivory
phyllosphere
Recent studies indicate that active prokaryotic assemblages are present in high-temperature oil reservoirs, including such genera as
A. Thermotoga
B. Thermoanaerobacter
C. Agrobacterium
D. only Thermotoga and Thermoanaerobacter
only Thermotoga and Thermoanaerobacter
- Microbial processes take place in
A. shallow subsurface where water flowing from the surface moves below the plant root zone.
B. regions where organic matter, originating from the Earth’s surface in times past, has been transformed by chemical and biological processes to yield coal.
C. zones where methane is being synthesized as a result of microbial activity.
D. all of the choices
D. all of the above
A large reserve of methane is found in a pocket below the ocean floor and isotope analysis revealed that the 13C/12C ratio is lower than that predicted by the natural occurrence of these isotopes. This finding suggests that the methane was produced by
A. a geochemical process.
B. the metabolic activity of microorganisms.
C. a radioactive decay process.
D. oxidation of sulfite.
the metabolic activity of microorganisms.
