micro2ex
which of the following methods is used to preserve food by slowing the metabolic processes of foodborne microbes?
freezing
which of the following could be used to sterilize plastic Petri plates in a plastic wrapper?
gamma radiation
oxidizing agents include all of the following except
glutaraldehyde
which of the following best describes the pattern of microbial death?
the cells in a population die at a constant rate
The initial effect of ionizing radiation on a cell is that it causes
the formation of highly reactive ions.
the antimicrobial activity of chlorine is due to which of the following?
the formation of hypochlorous acid
if you knew the sequence of nucleotides within a gene, which one of the following could you determine with the most accuracy?
the primary structure of the protein
the following is true of quaternary ammonium compounds EXCEPT
they are effective when combined with soaps
which of the following treatments is most effective for controlling microbial growth?
they are equivalent treatments
which one of the following is most resistant to chemical biocides?
gram-negative bacteria
all of the following substances are used to preserve foods except
microwaves
Genetic change in bacteria can be brought about by
mutation, conjugation, transduction, and transformation. ALL OF THE ABOVE.
According to the operon model, for the synthesis of an inducible enzyme to occur, the
substrate must bind to the repressor.
bones and tendons for transplants are decontaminated by
supercritical fluids
according to figure, the thermal death point is
the answer cannot be determined
what concentration of ethanol is the most effective bactericide?
70 percent
Which of the following statements is FALSE?
DNA replication proceeds in only direction around the bacterial chromosome.
T/F Any process that destroys the non-spore forming contaminants on inanimate objects is sterilization.
FALSE
T/F Desiccation is a reliable form of sterilization.
FALSE
T/F Microorganisms placed in high concentrations of salts and sugars undergo lysis.
FALSE
T/F The pH of the medium has no effect on the activity of the disinfectant being applied.
FALSE
T/F Ultraviolet light causes irreversible breaks in DNA strands.
FALSE
Which of the following statements regarding a bacterium that is R+ is FALSE?
It is F+
an enzyme that makes covalent bonds between the sugar of one nucleotide and the phosphate groups in another nucleotide in DNA is
RNA ligase
an enzyme that copies DNA to make a molecule of RNA is
RNA polymerase
Which of the following pairs is mismatched? (DNA/RNA)
RNA polymerase- makes a molecule of RNA from an RNA template
T/F Autoclaving is the most effective method of moist heat sterilization.
TRUE
T/F Moist heat destroys organisms by denaturing proteins.
TRUE
T/F Pseudomonas has been found growing in quaternary ammonium compounds.
TRUE
T/F Some antimicrobial chemicals are considered to be disinfectants and antiseptics.
TRUE
T/F The thermal death time is the time needed to kill all the bacteria in a particular culture at a certain temperature.
TRUE
T/F recombination will always alter a cell's genotype.
TRUE
Which of the following statements about bacteriosins are FALSE?
They cause food-poisoning symptoms.
Which of the following is NOT a product of transcription?
a new strand of DNA (transcription forms RNA)
A gene is best defined as
a sequence of nucleotides in DNA that codes for a functional product.
which of the following regarding antimicrobial control agents is FALSE?
a true antimicrobial control agent is equally effective against both bacteria and viruses.
all of the following substances are effective against nonenveloped viruses EXCEPT
alcohol
which of the following pairs is mismatched? (wound care)
alcohols -- open wounds
which of the following regarding antimicrobial control agents is false?
alcohols effectively inactivate nonenveloped viruses by attacking lipids
the miRNAs in a cell
allow different cells to produce different proteins
Transformation is the transfer of DNA from a donor to a recipient cell
as naked DNA in solution
which of the following pairs is mismatched?
bacteriostatic--kills vegetative bacterial cells
which of the following disinfectants act by disrupting the plasma membrane?
bisphenols
the mechanism by which the presence of glucose inhibits the lac operon is
catabolite repression
which of the following substances is used for surgical hand scrubs?
chlorhexidine
application of heat to living cells can result in all of the following EXCEPT
decreased thermal death time
the preservation of beef jerky from microbial growth relies on which method of microbial control?
dessication
an agent used to reduce the number of bacteria on a toiled would most accurately be called?
disinfectant
which of the following chemical agents is used for sterilization?
ethylene oxide
which of the following results in lethal damage to nucleic acids?
heat, radiation, and some chemicals
An enzyme produced in response to the presence of a substrate is called a
inducible enzyme.
an iodophor is a
iodine mixed with surfactant
ethylene oxide
is a sterilizing agent
which of the following is a limitation of the autoclave?
it cannot be used with heat-labile materials
which of the following is the best method to sterilize heat-labile solutions?
membrane filtration
repair of damaged DNA, in some instances and mechanisms, might be viewed as a race between an endocuclease and
methylase
all of the following factors contribute to hospital-acquired infections EXCEPT
none of the answers is correct/all may contribute to hospital-acquired infection
which of the following does NOT achieve sterilization?
pateurization
disinfection of water is achieved by all of the following except
peracetic acid
if you were preparing nutrient agar at home and did not have an autoclave, what could you use to sterilize the nutrient agar?
pressure cooker at 121C for 15 minutes
the cancer gene ras produces mRNA containing an extra exon that includes a number of UAA codons. Cancer cells produces ras mRNA missing this exon. This mistake is most likely due to a mistake by
snRNPs
an enzyme that catalyzes the cutting and resealing of DNA, and is translated from insertion sequences, is
transposase
DNA is constructed of
two strands of nucleotides running in an antiparallel configuration.
protein synthesis in eukaryotes is similar to the process in prokaryotes in that both eukaryotes and prokaryotes
use codons to determine polypeptide sequences