Exam #2 Flashcards
Which of the following diseases is (are) caused by prions?
Scrapie
Mad cow disease
Kuru and Creutzfeldt-Jakob Disease
All of the choices are correct.
all of the choices are correct
Prions consist of proteins and have no apparent nucleic acid genome T o F
True
Most bacterial and archaeal cells divide by _________
Binary Fission
Which of the following is the correct order for binary fission?
A septum forms at the midcell, the cell elongates, replicates its chromosome, and separates the chromosome into the two parts of the cell.
The cell elongates, a septum forms at midcell, the cell replicates its chromosome, and separates the chromosome into the two parts of the cell.
The cell elongates, replicates its chromosome, and separates the chromosome into the two parts of the cell, and a septum forms at midcell.
None of the choices are correct.
The cell elongates, replicates its chromosome, and separates the chromosome into the two parts of the cell, and a septum forms at midcell.
The ________ is a group of proteins needed for DNA synthesis that assembles at the origin of replication.
replisome
The process of forming a cross wall between two daughter cells is known as _________.
Septation
The site at which replication of DNA starts in bacterial cells is known as the
origin of replication
During cytokinesis, a critical step in septation is the assembly of the
z ring
Organisms that grow well at 0°C and have optimum growth temperatures of 15°C or lower are called?
psychrophiles
Organisms that do not require oxygen for growth but grow better in its presence are called
facultative anaerobes
Organisms that ignore oxygen and grow equally well in its presence or absence are called _________
aerotolerant
Organisms that are damaged by the normal atmospheric levels of oxygen (20%) but require oxygen at levels of 2–10% for growth are called
microaerophiles
Organisms that require increased pressure for optimum growth are called
barophilic
Most known microorganisms maintain their internal pH
near neutral (pH 7)
Membranes of some thermophilic Archaea are stabilized by ether-linked phospholipids. T o F
True
Membranes of thermophilic bacteria are stabilized by phospholipids with
fatty acids that tend to be more saturated
What is Quorum sensing?
is a phenomenon in which bacteria monitor their own population density
depends on the sensing of signal protein molecules
plays an important role in formation of biofilms by Pseudomonas aeruginosa
What are the four step of Quorum Sensing
- Surface (substratum) is preconditioned by environmental molecules.
- Microbes attach and detach from the preconditioned surface
- Microbes attach and detach from the preconditioned surface
- Biofilm matures and some microorganisms escape to the planktonic state.
Which of the following is a reason(s) for the decline in cell numbers during the death phase?
Depletion of nutrients
Accumulation of toxic waste materials
Depletion of O2
All of the choices are correct.
all of them are correct
A growth medium that favors the growth of some microorganisms but inhibits the growth of other microorganisms is
neither selective nor differential
both selective and differential
a differential medium
a selective medium
selective medium
A growth medium that distinguishes among different groups of bacteria on the basis of their biological characteristics is called a(n)
differential medium
When antiseptics and disinfectants are compared, antiseptics are generally _________.
less toxic
more toxic
equally as toxic
unpredictable in toxicity
less toxic
The destruction or removal of all viable organisms is called
Sterilization
The reduction of the microbial population to levels that are considered safe by public health standards is called
sanitization
Ultraviolet radiation is an effective means of sterilizing surfaces T o F
true
Dry heat methods usually require lower temperatures and shorter exposure times than moist heat methods to achieve the same degree of killing because of the drying effects of this form of heat. T o F
False
If one left a “pasteurized” flask of broth for a long time at room temperature, it would stay sterile forever, at least in principle. T o F
False
Which of the following is MOST effective against resistant endospores?
Multiple Choice
Autoclaving
Boiling
Pasteurization
All of these are equally effective against resistant endospores.
Autoclaving
Moist heat sterilizes by _________.
causing the formation of thymine dimers
denaturing proteins
causing the production of singlet oxygen
All of the choices are correct.
Denaturing proteins
The two most important alcohol germicides are _________ and _________
ethanol; isopropanol
Alcohols are widely used as antiseptics and disinfectants because they are effective against endospores as well as vegetative cells T o F
False
A drug that disrupts a microbial function not found in animal cells usually has a higher therapeutic index T o F
true
The ratio of toxic dose to therapeutic dose is called the
therapeutic index
The minimal lethal concentration (MLC) is the
lowest concentration of a drug that prevents growth of a particular pathogen
highest concentration of a drug that prevents growth of a particular pathogen
lowest concentration of a drug that kills a particular pathogen
highest concentration of a drug that kills a particular pathogen
lowest concentration of a drug that kills a particular pathogen
The lowest concentration of an antibiotic that prevents growth is the _________.
minimal inhibitory concentration (MIC)
minimal lethal concentration (MLC)
50% inhibitory dose
All of the choices are correct.
minimal inhibitory concentration (MIC)
Aminoglycoside antibiotics _________.
inhibit cell wall synthesis
inhibit folic acid biosynthesis
bind to the 30S ribosomal subunit
bind to bacterial DNA polymerase
bind to the 30S ribosomal subunit
Which of the following is a useful mechanism of action for an antibacterial drug?
Inhibition of cell wall synthesis
Inhibition of protein synthesis
Interference with RNA and DNA synthesis
All of the choices are correct.
all of these
Protein synthesis inhibitors have a low therapeutic index because they usually cannot discriminate between prokaryotic and eukaryotic ribosomes.
T o F
False
The antiviral drugs currently approved for use in HIV disease include _________
nucleoside reverse transcriptase inhibitors
nonnucleoside reverse transcriptase inhibitors
protease inhibitors
fusion inhibitors
All of the choices are correct.
all are correct
treatment of fungal infections is more difficult than treatment of bacterial infections because the greater metabolic similarity between the fungi and their hosts limits the ability of a drug to have a selective toxicity T O F
True
Which of the following is (are) used by microorganisms to become resistant to a particular drug?
Enzymatic inactivation of the drug
Exclusion of the drug from the cell
An alternate metabolic pathway that bypasses the drug-sensitive step
All of the choices are correct.
all of the choices are correct
A chemical reaction that requires an input of energy in order to proceed is
Endergonic
he change in _________is the amount of energy in a system that is available to do work
Free energy
The standard reduction potential of a redox reaction is a measure of the tendency of the _________ to _________ electrons.
reductant; gain
reductant; lose
oxidant; gain
oxidant; lose
reductant; lose
he energy required to bring the substrates of a reaction together in the correct way to reach the transition state is called
Activation energy
Enzyme activity can be controlled by _________.
allosteric regulation
covalent modification
feedback (end product) inhibition
All of the choices are correct.
all are correct
The net gain of ATP per molecule of glucose metabolized anaerobically via the Embden-Meyerhof pathway in PROKARYOTES is _________.
Multiple Choice
2
36
38
85
2
In addition to being used in the making of ATP, a proton motive force is used directly to power the rotation of bacterial flagella T o F
true
The theoretical maximum net gain of ATP per molecule of glucose metabolized aerobically in eukaryotes is
32
Which of the following may be used as sources of energy by chemolithotrophs?
Hydrogen gas
Reduced nitrogen compounds
Reduced sulfur compounds
All of the choices are correct.
all of them are correct
A newly described bacterial species has been shown to use CO2
as its carbon source. Its energy source and its source of reducing power (electrons) are inorganic chemicals. Which term would best describe this nutritional type?
Chemolithoheterotroph
Photoorganoheterotroph
Photolithoheterotroph
Chemolithoautotroph
Chemolithoautotroph
Which of the following is the major glycolytic pathway used by plants and animals?
Multiple Choice
Tricarboxylic acid cycle
Embden-Meyerhof pathway
Entner-Doudoroff pathway
Pentose phosphate pathway
Embden-Meyerhof pathway
How is ATP produced during fermentation?
Cyclic phosphorylation
Substrate-level phosphorylation
Oxidative phosphorylation
Use of proton motive force to drive ATP synthase
Chemosynthetic phosphorylation
Substrate-level phosphorylation
What enzymes hydrolyze proteins, releasing amino acids?
Tranaminases
Proteases
Decarboxylases
Deaminases
Proteases
The energy source for substrate-level phosphorylation (SLP) differs from that of oxidative phosphorylation (OP) in that _________.
SLP is driven using energy provided by a proton motive force, whereas the energy to remove a phosphate group from ATP during OP comes from the direct transfer of a phosphate group from a molecule with a lower phosphate transfer potential than ATP
OP is driven using energy provided by a proton motive force, whereas the energy to add a phosphate group to ADP during SLP comes from the direct transfer of a phosphate group from a molecule with a lower phosphate transfer potential than ATP
OP is driven using energy provided by a proton motive force, whereas the energy to add a phosphate group to ADP during SLP comes from the direct transfer of a phosphate group from a molecule with a higher phosphate transfer potential than ATP
SLP is driven using energy provided by a proton motive force, whereas the energy to add a phosphate group to ADP during OP comes from the direct transfer of a phosphate group from a molecule with a higher phosphate transfer potential than ATP
OP is driven using energy provided by a proton motive force, whereas the energy to add a phosphate group to ADP during SLP comes from the direct transfer of a phosphate group from a molecule with a higher phosphate transfer potential than ATPCorrect
Chemolithotrophs obtain their energy from _________.
inorganic molecules that directly transfer a phosphate group to ATP during substrate-level phosphorylation
inorganic molecules that are oxidized, providing electrons to create a proton motive force that drives oxidative
phosphorylation
organic molecules that are oxidized via a glycolytic pathway and the TCA cycle
inorganic molecules that are reduced, providing electrons to create a proton motive force that drives oxidative phosphorylation
inorganic molecules that are oxidized, providing electrons to create a proton motive force that drives oxidative
phosphorylation
Which of the following has the phases of the Calvin-Benson cycle in the correct order, starting with the entry of ribulose 1,5-bisphosphate?
Reduction phase, carboxylation phase, regeneration phase
Carboxylation phase, reduction phase, regeneration phase
Carboxylation phase, regeneration phase, reduction phase
Regeneration phase, carboxylation phase, reduction phas
Carboxylation phase, reduction phase, regeneration phase
Cells save energy and materials by using many of the same enzymes for both _________ and _________.
anabolism; catabolism
metabolism; catabolism
peptidoglycan; lipopolysaccharides
ATP; NADPH
anabolism; catabolism
Which of the following is the building structure for macromolecules?
Multiple Choice
Polymers
Monomers
Multimers
Proteins
Monomers
