In the Meselson-Stahl experiment, what happened after the E. coli was moved to the N14 medium and two rounds of cell division occurred? This result demonstrated that DNA replicated in a semi-conservative manner.  A. The DNA formed one band at the N15 density level and one band at the N14 density level.    B. The DNA formed one band between the N14 and N15 density levels and one band at the N14 density level.   .C. The DNA only formed one band between the N14 and N15 density levels.

If a researcher accidentally transformed the bacterial two hybrid plasmids ( pKT25-X and pUT18-Y) into a normal strain of E coli that produces adenylate cyclase, his/her experiment will: a. show a high lacZ activity in all tubes (control and experiment) because Proteins X and Y do not need to be interacting in order to activate lacZ gene prescription. b. not work because cells lack cAMP. c. need replicates in order to show true interaction between X and Y.

An 9 kb circular plasmid is cut with the EcoRI restriction enzyme, and the reaction products are run on a DNA gel and stained with ethidium bromide.  Bands of 1, 3 and 5 kb are seen. How many EcoRI sites are in the plasmid? Choose the one answer that is most correct. a) At least 2 b) At least 3 c) At least 1 d) None e) At least 4 f) At least 5

You isolated two bacteria from soil that you assumed were different species since they have different properties - for example, one is resistant to several antibiotics and the other is not. However, upon sequencing the 16S rRNA genes of the isolates, you have discovered that they are the same genus and species. When you extract the total DNA from each and run a gel, you discover the resistant strain has a plasmid in addition to the primary Chromosome. a. How might this strain have acquired the plasmid? b. What is definitely encoded on the plasmid given the information provided? c. How could you use fluorescence microscopy to determine if other bacteria in your soil suspension are carrying the same plasmid? Be sure to comment on the type of fluorescent probe, how it will interact with your sample, and how you will distinguish cells harboring the plasmid from the rest of the population (what will it look like).

You have used the technique of chromatin immunoprecipitation to isolate DNA fragments containing a DNA-binding protein of interest. Suppose that you wish to know whether a particular known DNA fragment is present in the isolated mixture. How might you detect its presence?

In Oswald Avery experiment, two strains of pneumococcus bacteria were used to infect mice. Explain how the experiment discovered that DNA is the transformation agent.

Answer part C of the following: A) E. coli DNA and binturong DNA are both 50% G-C. If you randomly shear E. coli DNA into 1000 bp fragments and put it through density gradient equilibrium centrifugation, you will find that all the DNA bands at the same place in the gradient, and if you graph the distribution of DNA fragments in the gradient you will get a single peak (see below). If you perform the same experiment with binturong DNA, you will find that a small fraction of the DNA fragments band separately in the gradient (at a different density) and give rise to a small "satellite" peak on a graph of the distribution of DNA fragments in the gradient (see below). Why do these two DNA samples give different results, when they're both 50% G-C? See graph B.    B) If you denatured the random 1000 bp fragments of binturong DNA that you produced in question 1a by heating them to 95ºC, and then cooled them down to 60ºC and allowed them to reanneal, you would find that approximately 15% of the…

If you performed PCR to amplify a gene region, and you began with 20 copies of double stranded genome, after 18 cycles, about how many double stranded copies of that region would you have (in theory)?

What observations are consistent with the conclusion that DNA serves as the genetic material in eukaryotes? Select the four correct statements. a. DNA content and ploidy in various cell types( sperm and somatic cells) are related b. DNA is found to be the only macromolecule in eukaryotes that has different subunits. c. Gene transfer is a direct evidence as it has been facilitated by recombinant DNA techniques. d. The correlation of the action and absorption spectra of ultraviolet light support the interpretation that DNA is a genetic material. e. DNA is shown to be present in ribosomes, matrix, and nucleus, where genetic function is performed. f. DNA is shown to be present in mitochondria, chloroplasts, and nucleus, where genetic function is performed.

You have two mutants of pQE. 1-CRYGD. One is 66 ng/uL and the other is 337 ng/uL. You need to add 1 ng to your competent  NEB Express Iq cells.  A. Can you accurately pipet the plasmid for each? Why or why not? B. How could you dilute the plasmid to obtain 50 uL of 0.5 ng/uL? C.How much of the new 0.5 ng/uL sample would you need to pipette for 1 ng