A student mixes some heat-killed-type IIS Streptococcus pneumonia bacteria with live type IIR bacteria and injects the mixture into a mouse. The mouse develops pneumonia and dies. The student recovers some type IIS bacteria from the dead mouse. If this is the only experiment conducted by the student, has the student demonstrated that transformation has taken place? What other reasons explain the presence of the type IIS bacteria in the dead mouse?

Type S Streptococcus pneumoniae bacterium is lethal and will kill its host. If heat inactivated the S strain dies and becomes nonlethal. Type R Streptococcus pneumoniae is a nonvirulent strain of bacteria. What would occur if one were to inject both the R strain and heat-killed S strains into a host organism such as the mouse? The R strain would be transformed into the virulent S strain and kill the host. Neither the S nor the R strain would change. The R strain would be transformed into the virulent S strain and not affect the host. The S strain would be transformed into the nonvirulent R strain and not affect the host The S strain would be transformed into the nonvirulent R strain and kill the host.

I read that vinyl chloride exposure is associated with an increased risk of a rare form of liver cancer (hepatic angiosarcoma), as well as brain and lung cancers, lymphoma, and leukemia.  But my question is what gene(s) are being mutated by this type of taxic gas?

You got an opportunity to join a professor lab who is working in-vivo model and specifically looking at the dysregulation of mitochondria in liver. He asked you to isolate mitochondria from a Rat liver and placed in an assay medium. Based on the knowledge you gain in this course so far, please answer the following questions: a) Which technique will you use to isolate mitochondria? b) What happens to the pH of the medium when the medium is kept anaerobic?  c) What happens when O2-saturated saline is added to the mixture?

In the bacterial transformation experiment, what is the primary purpose of using an ampicillin-containing medium?   In the bacterial transformation experiment, what is the primary purpose of using an ampicillin-containing medium?

Which of the following statements best explains why there are fewer colonies on plate IV than on plate III? (a) Plate IV is the positive control. (b) Not all bacterial cells were successfully transformed. (c) The bacteria on plate III did not mutate. (d) The plasmid inhibited bacterial growth. (e) Plate IV is the negative control.

In Hershey-Chase experiment, bacteriophages protein coats were tagged with radioactive isotope S-32. These phages were used to infect E. coli cells and the cells were further centrifuged to form pellets. Why was the radioactivity level of S-32 found greater outside the cells compared to the E. coli cell pellets? Explain briefly. If the experiment is repeated in the same manner but this time the phage protein coats are labelled with isotope X and the phage DNA with isotope Y, which isotope’s radioactivity will be found in greater amounts in the E. coli cell pellets after centrifugation? Explain briefly.

Usually, bacteria only make tryptophan when tryptophan is absent or available in low concentration. However, a particular bacterial mutation makes tryptophan all the time whether or not tryptophan is present. What could explain this phenotype? A) the terminator hairpin is unable to form B) the antiterminator hairpin is unable to form C) trpE is mutated D) trpD is mutated E) trpA is mutated

What is transformation? Describe Grifith’s experiment to show transformation? What did he prove from his experiment?

In the Meselson  experiment, would it have been possible to utilize N14 in the original bacteria and only allow growing bacteria to access N15 to build new (F1) bacteria and get the same results? Explain why. (I need an answer in full complete sentences with the question restated in the response.)