MBIO 3401 Exam 3 Questions and Verified Answers/Accurate Solutions| Already Graded A+
In anoxygenic photosynthesis, which compound (or compounds) is (are) used by purple and
green bacteria as a source of electrons for the reduction of CO2? H2O
In an ecological sense, the variety of photosynthetic pigments found among different groups of
photosynthetic bacteria allows them to: avoid direct competition by absorbing different
wavelengths of light
Rickettsias and Chlamydias are two unrelated groups of bacteria that nevertheless share a
unique characteristic. This characteristic is: they are both obligate intracellular parasites of
eukaryotes
what important soil process are these chemolithotrophic bacteria involved in? nitrification
a student in lab inoculates several spread plates of E. coli and then irradiated them with
ultraviolet light to determine the rate of cell killing. No decrease was seen in the number of
colonies on the irradiated plates compared to the non-irradiated plates. What mistake did this
student probably make? he left lids on the spread plates and the ultraviolet light was unable
to penetrate the plastic barrier
spirochetes that are known human pathogens include: two or more of the above answers
are correct
As discussed in lecture, which of the following bacteria are aerobic chemolithotrophs?
nitrobacter
The hypothesis has been proposed that magnetotactic bacteria sense the Earth's magnetic field
in order to: swim in the direction of a microaerophilic environment
What evidence suggest that cyanobacteria-like ancestor were present on the Earth as early as
3.5 billion years ago? fossilized stromatolites
, Many of the magnetotactic bacteria are found among the: spirilla
In lecture, Hyphomicrobium was given as an example of a: budding bacterium
Current estimates are that ___________ of the microorganisms in a typical environmental
smaple, such as soil or water, have bee cultivated before in the laboratory? less than 1%
The currently accepted division of all living organisms on earth int three domains is based on
differences in what fundamental characteristics? small subunit ribosomal RNA sequences
From reading your textbook, metagenomics refers to: using modern genomic techniques to
study entire microbial communities directly in their natural environments
From your reading in the textbook, enzymes that are used in the laboratory to recognize and
cleave DNA molecules at very specific bases sequences, often for the purpose of cloning, are
called: restriction endonucleases
One general characteristic of gene transfer processes in bacteria is: gene transfer is always
unidirectional (from donor to recipient)
A mutation occurs in the lac operon of E. coli. You observe the mutant is unable to bring lactose
into the cell. Which gene in the operon has been mutated? lacY
E. coli normally synthesizes the enzyme B-galactosidase when the sugar lactose is present but
not when it is absent. A strain of E. coli is isolated in the laboratory that always synthesizes B-
galactosidase regardless of whether lactose is present or not. What is the most likely
explanation for this isolate's phenotype? the strain carries a mutation in the gene encoding
the lactose repressor that eliminates its ability to bind to the operator of the lac operon
In anoxygenic photosynthesis, which compound (or compounds) is (are) used by purple and
green bacteria as a source of electrons for the reduction of CO2? H2O
In an ecological sense, the variety of photosynthetic pigments found among different groups of
photosynthetic bacteria allows them to: avoid direct competition by absorbing different
wavelengths of light
Rickettsias and Chlamydias are two unrelated groups of bacteria that nevertheless share a
unique characteristic. This characteristic is: they are both obligate intracellular parasites of
eukaryotes
what important soil process are these chemolithotrophic bacteria involved in? nitrification
a student in lab inoculates several spread plates of E. coli and then irradiated them with
ultraviolet light to determine the rate of cell killing. No decrease was seen in the number of
colonies on the irradiated plates compared to the non-irradiated plates. What mistake did this
student probably make? he left lids on the spread plates and the ultraviolet light was unable
to penetrate the plastic barrier
spirochetes that are known human pathogens include: two or more of the above answers
are correct
As discussed in lecture, which of the following bacteria are aerobic chemolithotrophs?
nitrobacter
The hypothesis has been proposed that magnetotactic bacteria sense the Earth's magnetic field
in order to: swim in the direction of a microaerophilic environment
What evidence suggest that cyanobacteria-like ancestor were present on the Earth as early as
3.5 billion years ago? fossilized stromatolites
, Many of the magnetotactic bacteria are found among the: spirilla
In lecture, Hyphomicrobium was given as an example of a: budding bacterium
Current estimates are that ___________ of the microorganisms in a typical environmental
smaple, such as soil or water, have bee cultivated before in the laboratory? less than 1%
The currently accepted division of all living organisms on earth int three domains is based on
differences in what fundamental characteristics? small subunit ribosomal RNA sequences
From reading your textbook, metagenomics refers to: using modern genomic techniques to
study entire microbial communities directly in their natural environments
From your reading in the textbook, enzymes that are used in the laboratory to recognize and
cleave DNA molecules at very specific bases sequences, often for the purpose of cloning, are
called: restriction endonucleases
One general characteristic of gene transfer processes in bacteria is: gene transfer is always
unidirectional (from donor to recipient)
A mutation occurs in the lac operon of E. coli. You observe the mutant is unable to bring lactose
into the cell. Which gene in the operon has been mutated? lacY
E. coli normally synthesizes the enzyme B-galactosidase when the sugar lactose is present but
not when it is absent. A strain of E. coli is isolated in the laboratory that always synthesizes B-
galactosidase regardless of whether lactose is present or not. What is the most likely
explanation for this isolate's phenotype? the strain carries a mutation in the gene encoding
the lactose repressor that eliminates its ability to bind to the operator of the lac operon
