15. Escherichia coli was grown for a period of time in 15N and transferred to 14N for two generations. Thenthe bacteria are lysed and the resulting DNA is fractionated in a Cs gradient. Compared to control bandsat 15N level (low) and the 14N level (high) and a medium band intermediate between the low and highbands, the results will be:A. There will be one high band of DNA.B. There will be two bands of DNA equally divided between medium and high.C. There will be two bands of DNA equally divided between medium and low.D. There will be one medium band of DNA.E. There will be one low band of DNA.

E. coli was first grown in 15N and then transferred to 14N. The bacteria was lysed and the DNA was…

15. Escherichia coli was grown for a period of time in 15N and transferred to 14N for two generations. Then the bacteria are lysed and the resulting DNA is fractionated in a Cs gradient. Compared to control bands at 15N level (low) and the 14N level (high) and a medium band intermediate between the low and high pands, the results will be: A. There will be one high band of DNA. B. There will be two bands of DNA equally divided between medium and high. C. There will be two bands of DNA equally divided between medium and low. D. There will be one medium band of DNA. E. There will be one low band of DNA.

15. Escherichia coli was grown for a period of time in 15N and transferred to 14N for two generations. Then the bacteria are lysed and the resulting DNA is fractionated in a Cs gradient. Compared to control bands at 15N level (low) and the 14N level (high) and a medium band intermediate between the low and high pands, the results will be: A. There will be one high band of DNA. B. There will be two bands of DNA equally divided between medium and high. C. There will be two bands of DNA equally divided between medium and low. D. There will be one medium band of DNA. E. There will be one low band of DNA.

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter18: Dna Technologies: Making And Using Genetically Altered Organisms, And Other Applications

Section: Chapter Questions

Problem 3TYK: Why are antibiotic resistance markers such as ampR important components of bacterial plasmid cloning...

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1) The Nde1 enzyme comes at a concentration of 40 U/ul. According to the manufacturer, the container has enough for 10,000 reactions of 2 ug of DNA, assuming that 1 U/ug of DNA is recommended. How many units in total does the packaging contain? At what concentration in U/ml does the enzyme come? If I had to use 10 U for a reaction of 10 ugs of DNA, how would I serve it? 2) A serially diluted phage solution is used to inoculate an E coli plate in the double-layer plate assay. In 24 hours you count 148 plaques. Considering that the original stock was 0.1, and that you used the sixth dilution of the series, what is the PFU for that phage in this strain of E coli? What is the dilution factor for this plate?
Why are antibiotic resistance markers such as ampR important components of bacterial plasmid cloning vectors? a. The plasmid must have resistance to accept DNA inserts. b. They allow the detection of plasmids that contain an inserted DNA fragment. c. They ensure the presence of the ori site. d. They ensure that the plasmid can be cut by a restriction enzyme. e. They allow identification of bacteria that have taken up a plasmid.
Which of the following is not correct for bacterial conjugation? a. Both Hfr and F+ bacteria have the ability to code for a sex pilus. b. After an F- cell has conjugated with an F+, its plasmid holds the F+ factor. c. The recipient cell is Hfr following conjugation. d. In an HfrF- conjugation, DNA of the main chromosomemoves to a recipient cell. e. Genes on the F factor encode proteins of the sex pilus.
Discuss how enzymes proofread and repair errors in DNA.
Which of the following statements about DNA is false? a. Phosphate is linked to the 5 and 3 carbons of adjacentdeoxyribose molecules. b. DNA is bidirectional in its synthesis. c. Each side of the helix is antiparallel to the other. d. The binding of adenine to thymine is through three hydrogenbonds. e. Avery identified DNA as the transforming factor in crossesbetween smooth and rough bacteria.
In the Hershey-Chase experiment with bacteriophages, (a) harmless bacterial cells permanently transformed into virulent cells (b) DNA was shown to be the transforming factor of earlier bacterial transformation experiments (c) the replication of DNA was conclusively shown to be semiconservative (d) viral DNA was shown to enter bacterial cells and cause the production of new viruses within the bacteria (e) viruses injected their proteins, not their DNA, into bacterial cells
27. You have a DNA sequence of 1400 bp. To characterize it, you decide to make a restriction map. Cutting with the first enzyme, you show by electrophoresis that the fragments produced are 400 and 1000 bp, respectively. After using the second enzyme, you recover 600-bp and 800-bp fragments. After treatment with both enzymes, fragments were 200, 400, and 800 bp. Draw the correct restriction map.
1. Write if the statement is true and modify the statement with the correct answer if its false a.Blue colonies in the white-blue screening provide sufficient information on the transfer of recombinant DNA in bacterial cells. b.In blue-white screening, it is only the blue colonies that have survived the effect of antibiotics in the media. c.Bacterial transformation simply means the insertion of a recombinant plasmid into a bacterial cell. d.Competent cells are those bacterial cells that can accept the entry or re-entry of plasmids.
1. Restriction enzymes in bacterial cytoplasm cut injected bacteriophage DNA wherever certain sequences occur. Why do you think these enzymes do not chop up the bacterial chromosome, which is exposed to the enzymes in the cytoplasm?
1. Write if the statement is true and modify the statement with the correct answer if its false a.White colonies represent those bacteria that do not express the genes for beta-galactosidase because restriction enzymes have cut the gene and ligase have not repaired the break b.Antibiotic resistance genes in bacterial transformation are used as marker genes because of ease of detection of transformants. c. Bacterial transformation simply means the insertion of a recombinant plasmid into a bacterial cell.
1. Given the following restriction endonucleases and the sequences of their corresponding restriction sites, which would be LEAST useful for cutting the plasmid and the foreign DNA to be inserted? [The arrows indicate where cuts are made.] (see img) a. EcoRI b. HindIII c. HaeIII d. BamHI 2. EcoRI and HindIII are two different restriction enzymes. If the DNA from two different sources were cut with either EcoRI or HindIII, which of the cut DNA fragments would NOT join together easily so that they could be sealed with ligase? a. E. coli DNA cut with EcoRI and human DNA cut with HindIII b. E. coli DNA cut with HindIII and mouse DNA cut with HindIII c. human DNA cut with EcoRI and chimpanzee DNA cut with EcoRI d. mouse liver DNA cut with HindIII and mouse kidney DNA cut with HindIII
1. In his transformation experiments, what did Griffith observe? a. Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form b. Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic c. Mutant mice were resistant to bacterial infections. d. Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains