Title: Genetic questions Post by: NAZ on Apr 17, 2012 hello all can anyone help me to find the answer for this multiple choices question? :( :s Which of the following sequences includes a clear 8 base pair palindrome? 5' – CCGATCGATCCC – 3' 5' – TGGGGTTTT G– 3' 5' – GGGGAAAA – 3' 5' – GATCCTAG – 3' 5' – AACCAACCAA – 3' Question In recombinant DNA technology, DNA is most often cut using DNA ligase. DNA polymerase. DNA gyrase. restriction endonucleases. terminal transferase. Question A linear DNA molecule has n target sites for restriction enzyme EcoRI. How many fragments will be produced after complete digestion? n – 1 n n + 1 2n – 1 2n + 2 Question A circular DNA molecule has n target sites for restriction enzyme EcoRI. How many fragments will be produced after complete digestion? n – 1 n n + 1 2n – 1 2n + 2 Question Recombinant DNA techniques typically require the action of DNA polymerase and phosphatase. restriction enzymes and DNA ligase. RNA polymerase and RNA primase. reverse transcriptase. DNA helicase. Question The polymerase chain reaction requires ssDNA primers that anneal to the same strand of template DNA, though at distant sites. anneal to opposite strands of template DNA at distant sites, with their 3' ends directed toward each other. anneal to opposite strands of template DNA at distant sites, with their 5' ends directed toward each other. anneal to each other to prime DNA polymerization. hybridize only to DNA within the open reading frame of a selected gene. Question The intermediate temperature cycle (72oC) in the polymerase chain reaction enables hybridization between the template DNA and the PCR primers. denaturation of the template DNA to enable primer access to matching sequence. activation of the primers to being the amplification procedure. activity of the thermostable DNA polymerase enzyme. a reduction of contamination in the amplification reaction. Question Which of the following is NOT true of a cDNA clone? cDNAs are generally copies of mRNA from expressed genes. Reverse transcriptase activity is required for cDNA cloning. cDNA clones lack exons, as introns are spliced together before cloning. cDNAs are typically smaller than the chromosomal sequence for a particular gene. cDNAs can be fused to a promoter to enable expression of the encoded gene. ] Question Identification of mRNA and initiation of priming for cDNA synthesis is accomplished by purifying only cytosolic RNAs before initiating the process. coupling cDNA synthesis to exon splicing. detecting the 5' cap sequence to initiation cDNA synthesis. use of oligo-dT to prime cDNA synthesis from the polyA tail. column purification of mRNA sequences. Question Perhaps the most common use of plasmid vectors is to enable the amplification of cloned DNA within a bacterial host cell. isolate viral DNA from infected cells. insert restriction enzyme cut sites into cDNAs. generate recombinant proteins. manipulate the cell biology of bacterial cells. Question A plasmid vector has a gene for erythromycin resistance (EryR) and a gene for ampicillin resistance (AmpR). The Amp gene is cut with restriction enzyme, and donor DNA treated with the same enzyme is added. What genotype of cells needs to be selected to show evidence of transformation? AmpREryR AmpREryS AmpSEryR AmpSEryS None of the above Question Assume that a cosmid will carry inserts of about 50 kb and that cosmids are used to clone a 3 Mb (megabase) genome. Assuming you are particularly lucky and have no duplication in your library, what is the smallest number of cosmid clones you would need for a “complete” genomic library? 3000 clones 600 clones 300 clones 60 clones 30 clones Question A radioactive probe is generated using the actin gene from yeast. This probe is used in a Southern blot analysis of EcoRI digested genomic DNA from the ciliated protozoan Tetrahymena thermophila. The autoradiogram shows a single-labeled band of 4 kb in size. This means that the Tetrahymena actin gene is 4 kb in size. the Tetrahymena actin gene is the same size as the yeast gene. the Tetrahymena actin gene is present in one copy in the genome. the Tetrahymena actin gene is present in four copies in the genome. the Tetrahymena actin gene is identical in sequence with the yeast gene. Question A wild-type Aspergillus strain is transformed with a plasmid carrying a hygromycin resistance allele, and cells are plated on hygromycin. One resistant colony showed an aberrant type of aerial hyphae. When crossed to wild type, the progeny were 1/2 normal hyphae, Hyg sensitive, and 1/2 aberrant hyphae, Hyg-resistant. The probable explanation is that the plasmid was inserted in a gene for normal hyphal development. the plasmid interfered with hyphal development. a mutation arose in a gene for hyphal development on the plasmid. a mutation arose in a gene for hyphal development on a recipient chromosome. the recipient was a heterokaryon carrying some mutant nuclei. Question The cDNA for a eukaryotic gene B is 900 nucleotide pairs long. A cDNA clone is used to isolate a genomic clone of gene B, and the gene is sequenced. From start to stop codon, the gene is found to be 1800 nucleotide pairs long. The most probable reason for the discrepancy is that the mRNA broke during cDNA synthesis. the gene is present as a tandem duplication. the gene has 900 nucleotide pairs of introns. the genomic clone is not really gene B, just a related gene. there was a sequencing error. Question In the Sanger sequencing method, the use of dideoxy adenosine triphosphate stops nucleotide polymerization opposite A's in the template strand. opposite T's in the template strand. opposite G's in the template strand. opposite C's in the template strand. opposite any base selected randomly in the template strand. Question This linear vector is comprised of bacteriophage genome components and can carry cloned DNA up to 15 kb in size. Answer pUC19 Lambda Fosmid Bacterial artificial chromosome T-vector Question The value of the beta-galactosidase gene in cloning could best described as Answer the gene provides valuable restriction enzyme cut sites. the gene “reports” if a recombinant product is formed. the gene confers resistance to antibiotics. the gene facilitates easier transfer of the DNA into bacterial cells. the gene encodes a special DNA ligase enzyme. Question Bacterial artificial chromosomes are comprised of Answer components of the bacterial F plasmid, and can carry large inserts (200,000 bp). fosmid DNA sequences, enabling the transfer of DNA between bacteria. viral lambda DNA sequences, enabling the transfer of DNA between bacteria. a bacterial chromosome, with some artificial components. recombinant proteins isolated from specific phage viruses. Question A cDNA library is produced from ______________ and is valued in the analysis of __________________. Answer chromosomal DNA digested with restriction enzymes; chromosomal organization chromosomal DNA digested with restriction enzymes; the promoter and regulatory elements of a particular gene a DNA copy of mRNA isolated from a group of cells; the protein-encoding open reading frame of a gene (no introns) a DNA copy of mRNA isolated from a group of cells; the promoter and regulatory elements of a particular gene protein sequences isolated from particular tissues; enzyme function encoded by a particular gene Question In the study of genetics, a “library” denotes 3 of 11 Answer the information carried in a digital database, such as GenBank. a collection of DNA fragments isolated from a particular group of cells (or tissue) representing the genetic content of those cells. a complex collection of restriction enzymes gathered for the purpose of restriction enzyme mapping. all the proteins present in a particular cell type, collected by protein extraction. a collection of books that explore the topic of genetics. Question What type of library would be most valuable in the isolation of promoter sequences found in front of a gene's transcriptional start site? Answer Genomic DNA library cDNA library miRNA library Mutant genomic DNA library Repetitive DNA library Question When seeking to identify the gene that is responsible for a particular cellular characteristic, scientists will generate cells carrying a recessive mutation that perturbs the characteristic of interest and then try to identify or “clone” the wild-type copy of that gene through functional complementation. This type of complementation could be described as Answer intensification of the recessive mutant trait via transferred plasmid DNA carrying the gene of interest. reversal (rescue) of the recessive mutant trait via transferred plasmid DNA carrying the gene of interest. identification of two different genes that both regulate the same cellular trait. a biochemical phenomenon where an enzymatic process is eliminated by plasmid DNA expressing a gene of interest. mutation of a gene of interest to complement an opposing biochemical pathway. Question In Southern and Northern blotting, the probe being used to analyze DNA or RNA identifies the target sequence via Answer attaching to the gene target via antibody-like protein-to-protein interactions. a DNA ligase-mediated attachment to the target DNA or RNA fragments. annealing between complementary sequences on the probe an the gene target. an enzymatic step that includes crosslinking between similar nucleic acid sequences. amplification during the polymerase chain reaction. Question Transgenic plants can be generated using T-DNA plasmid carrying a gene of interest. To get the DNA into the plant cells, the researchers Answer use a syringe needle to inject the DNA into pollen before fertilization. use a syringe needle to inject the DNA into groups of cells in the plant's root tissue. co-cultivate bacteria with T-DNA and plant cells, resulting in DNA transfer. add a mild detergent to cultures of plant cells to open holes in the cell wall. remove the plant cell's normal DNA and replace it with the T-DNA. Question Detection of a transgenic plant can be accomplished in a number of different ways, but often the initially transformed cells (in tissue culture) are enriched for the presence of a transgene by Answer screening groups of cells using the polymerase chain reaction. examining if the phenotype of the cells has been altered. placing the potentially transformed cells in the presence of a drug that inhibits the division of non-transgenic cells. microscopically examining the cells and isolating those that have “extra” DNA. None of the above. Transgenesis cannot be selected for in tissue culture. Question Homologous recombination in yeast facilitates Answer the segregation of genes during meiosis. the targeted replacement of a gene in a living yeast cell. the amplification of homologous yeast genes. the independent assortment of separate gene alleles. the expression of similar gene sequences via one promoter. Question Thymidine kinase is valuable in the targeting of mouse genes because Answer it enhances the efficiency of gene replacement. it suppresses expression of the target gene. it allows researcher to enrich cells for those that have undergone homologous recombination. transgenic cells are resistance to gancyclovir. transgenic cells are sensitive to gancyclovir. Question A transgenic mouse is different from a knockout mouse in that Answer transgenic mice have DNA added to their genome. transgenic mice do not have DNA added to their genome. the transgene is inserted at a random (ectopic) site in the genome. a knockout mouse is more healthy than a transgenic mouse. the knockout mouse is sterile. Question Which of the following organisms can be made transgenic by injection of DNA into the gonad, generated extrachromosomal arrays of the transgene in some egg cells? Mouse (Mus musculus) Yeast (Saccharomyces cerevisiae) Bacteria (Escherichia coli) Humans (Homo sapiens) Roundworm (Caenorhabditis elegans) Title: Re: Genetic questions Post by: chemb on Apr 17, 2012 Which of the following sequences includes a clear 8 base pair palindrome? 5' – CCGATCGATCCC – 3' 5' – TGGGGTTTT G– 3' 5' – GGGGAAAA – 3' 5' – GATCCTAG – 3' 5' – AACCAACCAA – 3' 5' – GATCCTAG – 3' Title: Re: Genetic questions Post by: chemb on Apr 17, 2012 In recombinant DNA technology, DNA is most often cut using DNA ligase. DNA polymerase. DNA gyrase. restriction endonucleases. terminal transferase. --> restriction endonucleases. Title: Re: Genetic questions Post by: Christine on Apr 29, 2012 Question
A plasmid vector has a gene for erythromycin resistance (EryR) and a gene for ampicillin resistance (AmpR). The Amp gene is cut with restriction enzyme, and donor DNA treated with the same enzyme is added. What genotype of cells needs to be selected to show evidence of transformation? AmpREryR AmpREryS AmpSEryR AmpSEryS None of the above Answer: AmpS EryR Question A radioactive probe is generated using the actin gene from yeast. This probe is used in a Southern blot analysis of EcoRI digested genomic DNA from the ciliated protozoan Tetrahymena thermophila. The autoradiogram shows a single-labeled band of 4 kb in size. This means that the Tetrahymena actin gene is 4 kb in size. the Tetrahymena actin gene is the same size as the yeast gene. the Tetrahymena actin gene is present in one copy in the genome. the Tetrahymena actin gene is present in four copies in the genome. the Tetrahymena actin gene is identical in sequence with the yeast gene. Answer: The Tetrahymena actin gene is present in one copy in the genome. Question The value of the beta-galactosidase gene in cloning could best described as Answer the gene provides valuable restriction enzyme cut sites. the gene “reports” if a recombinant product is formed. the gene confers resistance to antibiotics. the gene facilitates easier transfer of the DNA into bacterial cells. the gene encodes a special DNA ligase enzyme. Answer: the gene “reports” if a recombinant product is formed. Question In the study of genetics, a “library” denotes 3 of 11 Answer the information carried in a digital database, such as GenBank. a collection of DNA fragments isolated from a particular group of cells (or tissue) representing the genetic content of those cells. a complex collection of restriction enzymes gathered for the purpose of restriction enzyme mapping. all the proteins present in a particular cell type, collected by protein extraction. a collection of books that explore the topic of genetics. Answer: a collection of DNA fragments isolated from a particular group of cells (or tissue) representing the genetic content of those cells. Question What type of library would be most valuable in the isolation of promoter sequences found in front of a gene's transcriptional start site? Answer Genomic DNA library cDNA library miRNA library Mutant genomic DNA library Repetitive DNA library Answer: Genomic DNA library Question In Southern and Northern blotting, the probe being used to analyze DNA or RNA identifies the target sequence via Answer attaching to the gene target via antibody-like protein-to-protein interactions. a DNA ligase-mediated attachment to the target DNA or RNA fragments. annealing between complementary sequences on the probe an the gene target. an enzymatic step that includes crosslinking between similar nucleic acid sequences. amplification during the polymerase chain reaction. Answer: annealing between complementary sequences on the probe an the gene target. |