MicrobiologyLab Chap8

Which of the following hypotheses was developed following Griffith's 1928 experiment? A. DNA from dead encapsulated bacteria can transform living nonencapsulated bacteria into living encapsulated bacteria. B. Some pathogenic bacteria cannot be heat-killed. Bacterial virulence is related to temperature resistance. C. Streptococcus pneumoniae causes disease. D. Dead encapsulated bacteria can cause disease.

DNA from dead encapsulated bacteria can transform living nonencapsulated bacteria into living encapsulated bacteria.

Of the choices below, which is the LAST to happen during DNA replication? A. Primers are removed and replaced with DNA. B. Primase synthesizes primers for each strand. C. The two template strands of DNA are unwound. D. DNA ligase joins all the new pieces together.

DNA ligase joins all the new pieces together.

Use the genetic code in your textbook to solve this problem: The mRNA copied from a given gene is as follows: UACAAAGAAAUU. If base 2 were changed to U, what effect would this have? A. A missense mutation will occur. B. Transcription will stop. C. A nonsense mutation will occur. D. A frameshift mutation will result.

A missense mutation will occur.

Which of these statements is true about transduction? A. Segments of DNA move from one region of DNA to another. B. A virus is required for transfer of genetic material. C. Bacteria-bacteria contact is required. D. Recombination does not occur. E. Naked DNA is passed from bacterium to bacterium.

A virus is required for transfer of genetic material.

All of these statements are true about DNA replication except: A) Only one strand of the parent DNA serves as a template for a newly synthesized complementary strand. B) RNA polymerase synthesizes the primers. C) DNA ligase joins the small DNA fragments of the lagging strand. D) DNA polymerase is required to add new nucleotides to the growing ends of the DNA strands.

A) Only one strand of the parent DNA serves as a template for a newly synthesized complementary strand.

What is the consequence of a missense mutation? A. A missense mutation could lead to a shift in the reading frame of the mRNA. B. A missense mutation leads to the incorporation of the wrong amino acid into the protein. C. A missense mutation has no effect on the amino acid sequence of the protein. D. A missense mutation introduces a stop codon into an open reading frame.

B. A missense mutation leads to the incorporation of the wrong amino acid into the protein.

For the peptide with the amino acid sequence, proline-alanine-glycine (pro-ala-gly), the DNA template strand could have the sequence ________. A. GGC CGA CCG B. CCG GCC GGG C. GGU CGA CCA D. CGC GCC GGA E. CCU GCC GGC

GGC CGA CCG

Which one of the following would be the most likely to yield a recombinant cell after mating? Which of these statements is not true of translation? A. F+ cell and F- cell Three different nonsense codons code for termination of protein synthesis. B. Hfr cell and F+ cell The "language" of nucleotides is changed to the "language" of amino acids. C. F- cell and F+ cell A single mRNA may have several ribosomes attached. D. A molecule of tRNA can bind to both an mRNA molecule and an amino acid. E. Hfr cell and F- cell Each amino acid is coded for by a single codon.

Hfr cell and F- cell Each amino acid is coded for by a single codon.

Which of the following correctly describes the lac operon? A. It is repressible operon that is turned on in the presence of lactose. B. It is a constitutive operon that is unaffected by the presence of lactose. C. It is an inducible operon that is turned on in the presence of glucose. D. It is an inducible operon that is turned on if lactose is present and glucose is absent.

It is an inducible operon that is turned on if lactose is present and glucose is absent.

Which of the following processes is involved in the production of diphtheria toxin by C. diphtheria or erythrogenic toxin by Streptococcus pyogenes? A. specialized transduction B. mutation C. transformation D. conjugation E. generalized transduction

Specialized transduction

Which of the following statements concerning translation is correct? A. tRNAs enter the ribosome at the E site and leave from the A site. B. The ribosome stops protein synthesis when it reaches a nonsense codon in the mRNA. C. Each set of three nucleotides in the mRNA is called an anticodon. D. Amino acids are brought to the ribosome by the mRNA.

The ribosome stops protein synthesis when it reaches a nonsense codon in the mRNA.

Consider the polypeptide sequence encoded by the following DNA: TACAAAGAAATT If base number 6 is changed to G, how will this affect the polypeptide? A. A nonsense mutation will result in premature termination of the polypeptide. B. A frameshift mutation will result. C. There will be no change in the polypeptide. D. One amino acid will be changed. E. Translation will stop.

There will be no change in the polypeptide.

Which means of genetic transfer among bacteria involves a virus? A. mutation B. transformation C. conjugation D. transduction

Transduction

Your lab partner has mixed a dead tryptophan+ strain of Bacillus subtilis with a live tryptophan- strain and observes that her B. subtilis culture is now tryptophan+. The most likely explanation for this is ________. A. specialized transduction B. transformation C. conjugation D. generalized transduction E. mutation transformation

Transformation

Which of the following can cause changes in a sequence of several amino acids? A. a nonsense mutation B. a frameshift mutation C. a missense mutation D. a base substitution

a frameshift mutation

A mutation occurs that results in a codon change from UGU to UGA. UGU encodes a cysteine amino acid, and UGA is a stop codon. Therefore, this is an example of __________. A. a nonsense mutation B. a missense mutation C. a transposon D. a frameshift mutation

a nonsense mutation

In E. coli, Hfr cells ________. A. fuse with gram-positive cells by way of sticky surface materials B. do not form sex pili C. lack the genes typically carried on the F factor D. can pass main chromosome genes to a recipient cell E. typically pass the entire F factor to F- cells

can pass main chromosome genes to a recipient cell

Which of the following requires cell-to-cell contact? A. transformation B. conjugation C. mutation D. transduction

conjugation

Using the genetic code in your textbook, determine the polypeptide encoded by the RNA sequence AUGUUUCUUUAA. A. met-phe-leu B. phe-lys-lys-his C. asp-lys-phe D. tyr-lys-glu-ile

met-phe-leu

The major source of the genetic diversity among microorganisms upon which natural selection operates is? A. mutation B. transformation C. conjugation D. transduction

mutation

The antibiotic kasugamycin blocks binding of tRNA-Fmet (the bacterial tRNA that carries formylmethionine) to a ribosome. From this information, you can conclude that kasugamycin prevents __________. A. conjugation B. gene transcription C. protein synthesis D. DNA replication

protein synthesis

When the antibiotic chloramphenicol binds to the 50S portion of the ribosome, the effect is to ________. A. prevent tRNAs from binding to amino acids B. prevent transcription C. stop the ribosome from moving along the mRNA strand D. prevent RNA processing E. prevent peptide bond formation

stop the ribosome from moving along the mRNA strand

In the lac operon of E. coli, __________. A. the structural genes cease to be transcribed if allolactose binds to the repressor B. the gene for beta-galactosidase is regulated independently of a gene for lactose uptake by the cell C. the operon consists entirely of three structural genes for lactose utilization D. the structural genes for lactose utilization are constitutive E. the repressor protein binds to the operator in the absence of lactose

the repressor protein binds to the operator in the absence of lactose

For the amino acid aspartic acid (asp), ________. A. the corresponding tRNA would have the anticodon GAC B. the sequence of the DNA template would be CAG C. the sequence of the DNA template would be GAC D. the corresponding tRNA would have the anticodon CTA E. the sequence of the DNA template would be CTG

the sequence of the DNA template would be CTG