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