microbiology ch 11 & 12

A mutation that readily reverses to restore the original parental type would most likely be due to a(n) A. point mutation B. frameshift mutation C. insertion D. deletion

A

At which time period(s) during PCR thermocycling is/are hottest in temperature? A. during denaturation B. during DNA synthesis C. during annealing D. during primer extention

A

Expression vectors are designed to ensure that ________ can be efficiently ________. A. mRNA / transcribed B. DNA / transcribed C. mRNA / translated D. DNA / translated

A

If a bacterium carrying a plasmid that confers resistance to ampicillin is placed into medium without ampicillin, it may A. lose the plasmid because there is no selection for ampicillin resistance B. transfer resistance to other cultures in the laboratory. C. undergo a reversion mutation D. gain resistance to other antibiotics.

A

Microinsertions and microdeletions often result in ________ mutations A. frameshift mutation B. silent C. advantageous D. auxotrophic

A

Plasmids that govern their own transfer are known as A. conjugative B. tranformable C. transmutable D. tranfective

A

The F (fertility) plasmid contains a set of genes that encode for the ________ proteins that are essential in conjugative transfer of DNA. A. pili B. transformation C. flagella D. transduction

A

The designations Phe-, Leu-, and Ser+ refer to an organism's A. phenotype B. genotype C. plasmid type D. mutation type

A

The principle behind nucleic acid probe design is that the probe itself must contain A. a key complementary part of the target gene sequence of interest. B. all of the nucleotide sequence of the gene of interest to conclusively identify the gene C. an antibody to specifically bind to the gene of interest. D. at least three separate complementary regions of the gene of interest.

A

The uptake of free DNA from the environment is a process called ________, while transfer of DNA with cell-to-cell contact is a process called ________. A. transformation / conjugation B. transduction / conjugation C. congugation / transduction D. conjugation / transformation

A

What is the first step in constructing a metagenomic library from RNA? A. The RNA must be converted to cDNA B. "The RNA must be amplified through PCR, producing many RNA copies" C. The RNA must be screened to identify the genes of interest D. The RNA must be inserted into plasmid vectors

A

Which process listed below allows genetic material to be transferred from a virus-like particle that lacks genes for its own replication? A. gene transfer through a gene transfer agent B. transformation of a linear piece of DNA C. conjugation of an F+ plasmid D. transduction by a dsDNA phage Mu

A

Which of the following is NOT required for homologous recombination? A. an Hfr chromosome B. RecA C. an endonuclease D. proteins having helicase activity

A.

Cells that have "insertional inactivation"of the lacZ gene are A. blue B. white C. yellow D. green

B

Cosmids are a type of A. bacterial artificial chromosomes (BACs) B. cloning vector C.heat stable polymerase. D. RNA/DNA hybrid.

B

F-strains of Escherichia coli A. have the F factor as a plasmid. B. do not have an F factor C. transfer the F factor to recipient cells at a high frequency. D. have an integrated F factor

B

If a protein that could be toxic to the expression host needs to be expressed in large quantities, then it is best to select an expression vector that A. is not able to be replicated. B. is inducible C. is attached to a normal cell promoter. D. allows continual expression of the protein

B

In the bacterial world, a gene located on which of the following would be the LEAST likely to be transferred? A. a resistance plasmid B. the chromosome C. an F plasmid D. a transducing phage

B

What is the difference between PCR and RT-PCR? A. Only PCR makes many copies of DNA rapidly. B. RT-PCR uses an RNA template whereas PCR uses a DNA template. C. Only PCR produces cDNA D. PCR uses a single stranded template whereas RT-PCR uses a double-stranded template.

B

A mutant that has a nutritional requirement for growth is called a(n) A. ogranotroph B. autotroph C. auxotroph D. heterotroph

C

A(n) ________ gene is a gene that encodes a protein that is easy to detect and assay. A. encoder B. translational C. reporter D. recorder

C

Consider the following experiment. Large populations (millions of cells) of two mutant strains of Escherichia coli are mixed (each mutant population requires a different, single amino acid). After plating them onto a minimal medium, 45 colonies grew. Which of the following may explain this result? A. The colonies may be due to back mutation (reversion). B. The colonies may be due to recombination. C. Either A or B is possible. D. Neither A nor B is possible.

C

F+ strains of Escherichia coli A. do not have an F factor B. transfer the F factor to recipient cells at a high frequency C. have the F factor as a plasmid. D. have an integrated F factor

C

Lysogeny probably carries a strong selective advantage for the host cell because it A. confers resistance to infection by viruses of a different type (or strain). B. prevents cell lysis C. confers resistance to infection by viruses of the same type. D. confers resistance to infection by many virus types and prevent cell lysis.

C

The CRISPR system A. synthesizes gene transfer agents during stationary phase. B. repairs DNA and increases DNA damage tolerance during times of stress. C. recognizes foreign DNA sequences that have previously entered the cell and directs the Cas proteins to destroy them. D. facilitates homologous recombination through a complex system of proteins and clustered repeats

C

Transposition is a(n) A. analogous recombination event. B. general recombination event C. site-specific recombination event D. homologous recombination event.

C

What makes eukaryotic transcripts easier to isolate than bacterial transcripts? A. Eukaryotic transcripts are not methylated but their genes are often methylated B. Larger transcript size in eukaryotes enables easy size-selection methods. C. mRNA is polyadenylated in eukaryotes D. Transcripts are the most abundant RNAs in eukaryotes.

C

A polymerase chain reaction (PCR) copies an individual gene segment in vitro with a(n) ________ primer(s). A. individual RNA B. individual DNA C. pair of RNA D. pair of DNA

D

Consider a mutation in which the change is from UAC to UAU. Both codons specify the amino acid tyrosine. Which type of point mutation is this? A. frameshift mutation B. nonsense mutation C. missense mutation D. silent mutation

D

Insertion sequences may be found in A. phage B. chromosome C. plasmid D. A, B and C are correct

D

The genes encoding green fluorescent protein (GFP) and _-galactosidase are typically used in cloning as A. transcription regulators B. global control regulators C. promoter sequences D. reporter genes

D

Which of the following methods may introduce foreign DNA into a recipient? A. transformation B. transduction C. conjugation D. A,B and C are all correct

D

You work for a biotechnology company that uses Streptomyces strains to produce pharmaceutical products. A phage has infected and killed some of your Streptomyces strains during production, resulting in dramatically decreased yields. To protect the strains from infection you propose to A. transform the Streptomyces strains with plasmids encoding antibody proteins that will protect them from phage infection. B. infect the Streptomyces strains with a helper phage that will help the strains resist infection. C. introduce gene transfer agents into the Streptomyces cultures to transfer antibiotic resistance genes into your Streptomyces strains D. design and insert CRISPR spacer sequences into the genomes of your strains that are complementary to the genomes of the phages that are infecting the cultures.

D

A phage can be infectious even if all of its DNA has been replaced by bacterial DNA. TRUE OR FALSE

FALSE

Bacterial mating (or conjugation) is a bidirectional process where nucleic acids (DNA or RNA) are transferred between two cells TRUE OR FALSE

FALSE

High expression levels of a eukaryotic gene in a bacterium such as Escherichia coli cannot be accomplished due to the presence of introns. TRUE OR FALSE

FALSE

In a prokaryotic genome, either insertion elements OR transposons are present, but both are never present at the same time. TRUE OR FALSE

FALSE

A common reporter protein is green fluorescent protein (GFP TRUE OR FALSE

TRUE

Although various codons often code for the same amino acid, it is important to choose the codon preferred by the expression host itself. TRUE OR FALSE

TRUE

DNA ligase mediates the insertion of foreign DNA into a vector, but it will only be able to do so if the inserts and vector have matching sticky ends, or blunt ends. TRUE OR FALSE

TRUE

DNA polymerases from Escherichia coli cannot be used to artificially copy gene sequences with a thermocycler. TRUE OR FALSE

TRUE

Lysogeny is essential for the virulence of many pathogenic bacterial strains. TRUE OR FALSE

TRUE

Many Bacteria isolated from nature are natural lysogens TRUE OR FALSE

TRUE

Most plasmids are circular rather than linear. TRUE OR FALSE

TRUE

One important advantage of eukaryotic cells as hosts for cloning vectors is that they already possess the complex RNA and posttranslational processing systems required for the production of eukaryotic proteins. TRUE OR FALSE

TRUE

One method to circumvent issues with introns when expressing a eukaryotic gene in a bacterium is to simply clone the mature transcript. TRUE OR FALSE

TRUE

The key steps in cloning a foreign gene into a vector, regardless of the application, involve isolating the insert fragment, ligating the insert into a vector, and transforming it into a host. TRUE OR FALSE

TRUE

The use of transposons to generate mutations is a convenient way to create bacterial mutations in the laboratory TRUE OR FALSE

TRUE

Toxigenicity in Corynebacterium diphtheriae is due to phage conversion TRUE OR FALSE

TRUE

Transposons can be found on many genetic elements, including plasmids, chromosomes, and viral genomes. TRUE OR FALSE

TRUE