Micr-2123 Midterm Exam Questions with Revised Answers – UPDATED!!!
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Course
Micr-2123
Institution
Micr-2123
Micr-2123 Midterm Exam Questions with Revised Answers – UPDATED!!!
The proteins of the electron transport systems are usually - Answer-located within a membrane.
Which of the following forms of energy production does NOT involve the formation of a proton gradient to synthesize ATP? - Answer-F...
Micr-2123 Midterm Exam Questions with
Revised Answers – UPDATED!!!
The proteins of the electron transport systems are usually - Answer-located within a
membrane.
Which of the following forms of energy production does NOT involve the formation of a
proton gradient to synthesize ATP? - Answer-Fermentation
The proton motive force is a source of energy that can directly power all of the following
EXCEPT the - Answer-synthesis of proteins from amino acids.
Some organisms can create a sodium motive force by pumping sodium ions across a
membrane using the energy of an electron transport system. In order for this sodium
motive force to provide useful energy for the cell, the organism must containChoose
one: - Answer-an Na+-driven ATP synthase.
What determines which electron donor and electron acceptor a given microbe uses in
its anaerobic ETS? - Answer-The available donors and acceptors will induce gene
expression of their redox enzymes, thereby allowing their use.
Photoheterotrophic organisms - Answer-can use light as an energy source, but must still
acquire reduced carbon from the environment.
Metabolism using an electron transport system is classified based on the nature of the
initial electron donors and terminal electron acceptors. Lithotrophy uses __________
molecules as the __________ electron __________. - Answer-inorganic; initial; donors
What is the most likely explanation for the high numbers of sulfate reducers present in
marine environments? - Answer-Sulfate is a very abundant anion in seawater, second
only to chloride.
All of the following types of metabolism use a membrane-associated electron transport
system (ETS) EXCEPT for - Answer-fermentation.
Cells do not store NH4+. Instead, NH4+ is deprotonated to NH3, which diffuses across
the cell membrane and is lost. As a result, NH4+ is immediately assimilated into organic
molecules by which of the following? - Answer-glutamate synthetase
Which of the following organisms or structures does not conduct the Calvin cycle? -
Answer-archaea
, Carboxysomes are structures found in cyanobacteria and chloroplasts. They consist of
a protein shell that contains the enzyme Rubisco. The purpose of the carboxysome is to
trap - Answer-CO2 so that it reaches concentrations necessary to drive Rubisco.
In the Calvin cycle, carbon dioxide is covalently incorporated into glucose. This is known
as which of the following? - Answer-CO2 fixation
In the absence of the antimicrobial drug, would the resistant strain or the sensitive strain
have a selective advantage? Why? - Answer-The sensitive strain would have the
selective advantage because it would not expend energy or other resources producing
the unneeded pump in the absence of the drug.
Which of the following statements is true?Choose one:
A. Not all ecosystems require fixed nitrogen
.B. All living organisms depend on nitrogen-fixing prokaryotes
.C. Organisms that fix nitrogen cannot fix CO2.
D. All living organisms can fix nitrogen. - Answer-All living organisms depend on
nitrogen-fixing prokaryotes.
Which of the following is not an example of anabolism? - Answer-energy production
Which of the following is used to hydrogenate fatty acids during biosynthesis? - Answer-
NADPH
Fatty acid molecules are made from repeating subunits in a cyclic pathway that feeds its
products back repeatedly as substrates. This means that the synthesis of these
molecules - Answer-requires only a small number of enzymes.
Filamentous cyanobacteria form specialized cells that have lost the ability to perform
photosynthesis and so do not produce oxygen. These cells, called __________,
maintain anoxic conditions for nitrogenase. - Answer-heterocysts
Which of the following organisms are unable to fix nitrogen? - Answer-yeasts, such as
Candida albicans
In the nitrogenase enzyme complex, N2 is completely - Answer-reduced to NH3.
Which process produces acetyl-CoA? - Answer-glucose catabolism
Which of the following biosynthetic pathways include(s) the intermediate 5-
phosphoribosyl-1-pyrophosphate (PRPP)? - Answer-both purine and pyrimidine
synthesis
Biosynthetic pathways often use multiple levels of gene regulation to control expression
of the enzymes required because - Answer-the energy expenditure for these pathways
is very high, so the gene expression needs to be controlled.
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