Final Exam Assignment Example | Topics and Well Written Essays - 1250 words - 4

Final Exam - Assignment Example P3 initiates RNAIII that codes 6-hemolysin. P2 operon is 3Kb in length. It is unique when compared to P3 since it has up to four open reading frames, agrA, agrB, agrC, and agrD. The agrA controls the sensory transduction while agrB is responsible for the production of histidine phosphokinase in bacteria. Due to mutations, defects may occur in any one of four open reading frames, the resulting strains don’t have P2 and P3 transcripts, beside they become arg-. These strains cannot initiate transcription from the P2 and P3. Insertion at C1Ai site in the RNARIII region in P3 results in inactivation of arg functions. 2. a) ÃŽ ²-lactamase has higher activity as compared to the normal P2 and P3 promoters, and thus ÃŽ ²-lactamase can make other existing non-useful plasmids like p1524 unstable. Using P2 and P3 instead of ÃŽ ²-lactamase allows expression of the p15424, and this interferes with the results. b) RN6390B, arg+ produces stronger signals for alpha and beta hemolysins than does RN69 11, a null-arg strain, whose signal is extremely weak. If the researcher used arg+ instead, he would not obtain the same results due to interference by other unnecessary signals. c) When a B lymphocyte secretes antibodies that are directed towards a specific epitope on an antigen, we call the antibodies monoclonal. However, when a significant number of antibodies are secreted that have different affinities and specificities towards different epitopes, we call them polyclonal antibodies. B- hemolysin antibody is a polyclonal antibody, has a wide range of affinities and specificities and thus it can detect any antigen present in its environment. d) In anti-b blot, protein A produces a stronger signal for arg-a42 and no signal in arg-a40. The signal for B-hemolysin is present only in arg-a40 and not arg-a42. These results mean that different regions of P3 codes for different chemicals. 3. The author used RN7220 because it can increase the hla