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62 terms

Microbilogy Lecture Test

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Which substance in the following reaction is being reduced?
acetaldehyde
Which of the following reactions produces the most molecules of ATP during aerobic metabolism?
acetyl CoA -> CO2 -> H2O
Which of the following processes does not generate ATP?
the Calvin-Benson cycle
Which of the following compounds has the greatest amount of energy for a cell?
glucose
Which of the following is the best definition of the Krebs cycle?
a series of chemical reactions in which NADH is produced from the oxidation of pyruvic acid
Which of the following is the best definition of respiration?
a sequence of carrier molecules with an inorganic molecue as the final electron acceptor
Which culture produces the most lactic acid?
E. coli growing in glucose broth at 35C without O2 for 5 days
Which culture produces the most ATP?
E. coli growing in glucose broth at 35C with O2 for 5 days
Which culture uses NAD+?
both a and b
Which culture uses the most glucose?
E. coli growing in glucose broth at 35C without O2 for 5 days
Which of the following does not kill endospores?
pasteurization
Which of the following is most efective for sterilizing mattresses and plastic Petri dishes?
ethylene oxide
Which of these disinfectants does not act by disrupting the plasma membrane?
halogens
Which of the following cannot be used to sterilize a heat-labile solution stored in a plastic container?
autoclaving
Which of the following is not a characteristic of quaternary ammonium compounds?
sporicidal
A classmate is trying to determine how a disinfectant might kill cells. You observed that when he spilled the disinfectant in your reduced litmus milk, the litmus turned blue again. You suggest to your classmate that
the disinfectant might oxidize molecules
Which of the following is most likely to be bactericidal?
ionizing radiation
Which of the following is used to control microbial growth in foods?
organic acids
Which disinfectant is the most effective?
disinfectant b the one with all +'s going down
Which disinfectant is bactericidal?
all of them
The transfer of DNA from a donor to a recipient cell by a bacteriophage?
transduction
The transfer of DNA from a donor to a recipient as naked DNA in solution?
transformation
Feedback inhibition differs from repression because feedback inhibition
stops the action of preexisting enzymes
Bacteria can acquire antibiotic resistance by
all of the above mutation, insertion of transposons, acquiring plasmids
Suppose you inoculate three flasks of minimal salts broth with E. coli. Flask A contains glucose. Flask B contains glucose and lactose. Flask C contains lactose. After a few hours of incubation, you test the flasks for the presence of b-galactosidase. Which flask do you predict will have this enzyme?
the one that has lactose in it only
Plasmids differ from transposons because plasmids
are self-replicated outside the chromosome
The mechanism by which the presence of glucose inhibits the lac operon
catabolite repression
The mechanism by which lactose controls the lac operon
induction
Two daughter cells are most likely to inherit which one of the following from the parent cell?
a change in a nucleotide in DNA
Which of the following is not a method of horizontal gene transfer?
binary fission
Restriction enzymes were first discovered with the observation that
phage DNA is destroyed in a host cell
The DNA probe, 3' -GGCTTA, will hybridize with which of the following?
5' - CCGAAT
Which of the following is the fourth basic step to genetically modify a cell?
ligation
The following enzymes are used to make cDNA. What is the second enzyme used to make cDNA?
ribozyme
If you put a gene in a virus, the next step in genetic modification would be
transduction
You have a small gene that you want replicated by PCR. You add radioactively labeled nucleotides to the PCR thermalcycler. After three replication cycles, what percentage of DNA single strands are radiocatively labeled?
87.5%
Pieces of human DNA stored in yeast cells
library
A population of cells carrying a desired plasmid
clone
Self-replicating DNA for transmitting a gene from one organism to another
vector
A gene that hybridizes with mRNA
antisense
Which of the following pairs is mismatched?
antihelminthic -- inhibition of cell wall synthesis
All of the following are modes of action of antiviral drugs except?
inhibition of protein synthesis at 70S ribosomes
Which of the following modes of action would not be fungicidal?
inhibition of peptidoglycan synthesis
An antimicrobial agent should meet all of the following criteria except
the production of hypersensitivites
The most selective antimicrobial activity would be exhibited by a drug that
inhibits cell wall synthesis
Antibiotics that inhibit translation have side effects
at the 70S ribosomes in eukaryotic cells
Which of the following will not affect eukaryotic cells?
all of the above will affect them
Cell membrane damage causes death because
cell contents leak out
A drug that intercalates into DNA has the following effects. Which one leads to the others?
It interferes with DNA replication
Chloramphenicol binds to the 50S portion of a ribosome, which will interfere with
translation in prokaryotic cells.
Glucose + lactose
line with nothing on it
Glucose/ no lactose
line with R on it
Lactose / no glucose
line with polymerase and SA on it
No glucose/ no lactose
line with polymerase, SA, and R on it
What is the inducer for the lactose operon?
the repressor protein
In the above diagram what does S represent, and under what conditions is it produced by the cell?
Signal protein and it is produced by the cell when ...
Inhibition of cell wall synthesis?
Penicillin - narrow spectrum - gram positive
Injury Plasma membrane?
Polymyxin B - narrow spectrum - gram negative - topical
Inhibition of protein synthesis?
Tetracyclines - broad spectrum
Inhibition of synthesis of metabolites?
Sulfa drugs - broad spectrum
Inhibition of nucleic acid transcription/translation
Rifampin - broad spectrum
Inhibitors of protein synthesis interfere with translation on the 50S portion of the 70S bacterial ribosome. Although eukaryotic cells use an 80S ribosome for protein synthesis, the antibiotic can still pose a risk for eukaryotic cells. why?
Because in the mitochondria of eukaryotic cells there are 50S portions of proteins