1. When Griffith injected mice with a combination of live rough-strain and heat-killed smooth-strain pneumococci, he discovered that (a) the mice were unharmed (b) the dead mice contained living rough-strain bacteria (c) the dead mice contained living smooth-strain bacteria (d) DNA had been transferred from the smooth-strain bacteria to the mice (e) DNA had been transferred from the rough-strain bacteria to the smooth-strain bacteria

1. When Griffith injected mice with a combination of live rough-strain and heat-killed smooth-strain pneumococci, he discovered that (a) the mice were unharmed (b) the dead mice contained living rough-strain bacteria (c) the dead mice contained living smooth-strain bacteria (d) DNA had been transferred from the smooth-strain bacteria to the mice (e) DNA had been transferred from the rough-strain bacteria to the smooth-strain bacteria

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter8: The Structure, Replication, And Chromosomal Organization Of Dna

Section: Chapter Questions

Problem 6QP: Recently, scientists discovered that a rare disorder called polkadotism is caused by a bacterial...

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If you extract the DNA of the coliphage φ X174, you willfind that its composition is 25 percent A, 33 percent T,24 percent G, and 18 percent C. Does this compositionmake sense in regard to Chargaff’s rules? How wouldyou interpret this result? How might such a phage replicate its DNA
This image shows DNA (gray) interacting with a computergenerated model of a TAL protein (multicolored), one of afamily of proteins found only in a species of the bacteriumXanthomonas. The bacterium uses proteins like this one to findspecific gene sequences in cells of the organisms it infects, suchas tomatoes, rice, and citrus fruits. Given what you know aboutDNA structure and considering the image above, discuss howthe TAL protein’s structure suggests that it functions
. The double-stranded circular DNA molecule thatforms the genome of the SV40 tumor virus can be denatured into single-stranded DNA molecules. Becausethe base composition of the two strands differs, thestrands can be separated on the basis of their densityinto two strands designated W(atson) and C(rick). When each of the purified preparations of the single strands was mixed with mRNA from cells infectedwith the virus, hybrids were formed between the RNAand DNA. Closer analysis of these hybridizationsshowed that RNAs that hybridized with the W preparation were different from RNAs that hybridized withthe C preparation. What does this tell you about thetranscription templates for the different classes ofRNAs?
On further analysis of the DNA described in conceptual questionC21, you discover that the triplex DNA in this alien organism iscomposed of a double helix with a third strand wound within themajor groove (just like the DNA in Figure shown). How would youpropose that this DNA is able to replicate itself? In your answer,be specific about the base-pairing rules within the double helixand which part of the triplex DNA would be replicated first.
A bacterium has a genome size of 4.4 Mb. If a researchercarries out shotgun DNA sequencing and sequences a totalof 19 Mb, what is the probability that a base will be leftunsequenced? What percentage of the total genome will beleft unsequenced?
In the Western blot shown here, proteins were isolated from redblood cells and muscle cells from two different individuals. Oneindividual was unaffected, and the other suffered from a diseaseknown as thalassemia, which involves a defect in hemoglobin. Theblot was exposed to an antibody that recognizes β globin, whichis one of the polypeptides that constitute hemoglobin. Equal totalamounts of cellular proteins were added to each lane. Explain these results.
If you compare the frequency of the sixteen pos-sible dinucleotide sequences in the E. coli and humangenomes, there are no striking differences except for onedinucleotide, 5ʹ-CG-3ʹ. The frequency of CG dinucleotidesin the human genome is significantly lower than in E. coliand significantly lower than expected by chance. Why doyou suppose that CG dinucleotides are underrepresentedin the human genome?
Calculate the concentration of plasmid DNA if OD260 value is 0.74 and OD280 valueis 0.35 (taken into account the dilution factor (DF) of 20, and 1 O.D. at 260 nm for doublestranded DNA = 50 ng/ul of dsDNA).
An interesting trait that some bacteria exhibit is resistance to beingkilled by antibiotics. For example, certain strains of bacteria areresistant to tetracycline, whereas other strains are sensitive to tetracycline.Describe an experiment you would carry out to demonstratethat tetracycline resistance is an inherited trait encoded bythe DNA of the resistant strain.
For each individual on each gel, determine if the individual is homozygous for presence of the Alu insertion(++), heterozygous (+-), homozygous for the absence of the Alu insertion (-), or if the results are inconclusive (I) (explain what makes you decide your determination, in detail). Explain what may have caused any unexpected bands (neither 850 nor 550) or lack of bands.
Mutations in the dnaA gene of E. coli are lethal and canonly be studied following the isolation of conditional,temperature-sensitive mutations. Such mutant strains grownicely and replicate their DNA at the permissive temperatureof 18°C, but they do not grow or replicate their DNA at therestrictive temperature of 37°C. Two observations were usefulin determiningthe function of the DnaA protein product.First, in vitro studies using DNA templates that haveunwound do not require the DnaA protein. Second, if intactcells are grown at 18°C and are then shifted to 37°C, DNAsynthesis continues at this temperature until one roundof replication is completed and then stops. What do theseobservationssuggest about the role of the dnaA gene product?
To determine the reproducibility of mutation fre-quency measurements, you do the following experiment.You inoculate each of 10 cultures with a single E. coli bac-terium, allow the cultures to grow until each contains 106cells, and then measure the number of cells in each culturethat carry a mutation in your gene of interest. You were sosurprised by the initial results that you repeated the experi-ment to confirm them. Both sets of results display the sameextreme variability, as shown in Table Q5–1. Assuming thatthe rate of mutation is constant, why do you suppose thereis so much variation in the frequencies of mutant cells indifferent cultures?