Question

1. Do you think bacteriophages are likely to be more or less diverse than prokaryotes? Than eukaryotes? Why?
2. Is a plaque the result of the lytic or lysogenic pathway of the phage lifecycle? Explain.
3. Why were you instructed to make three dilutions of the phage in this experiment? What purpose does this serve the experiment?

Answer 1

1 The  main reason why Bacteriophages are more or less diverse than prokaryotes and eukaryotes is that, despite their number of ratio is abundant still the genetic diversity of them is less distinguished, and their functions remain unknown. It is mainly because they are isolated on small number that implies that few of the sequences are known and comparative analysis of genome is not possible on large scale. 2. Plaques are clear areas Found in the cell formed by phage due to lysis. The plaque formation can follow both lyric pathway or lysogenic pathway as it generally depends on one factor that is multiplicity of infection(MOI). Lyric pathway is followed when cells are infected with single phage and it diffuses neighbouring cells and lysing results in circular area of of cell which are infected and MOI is low. Alternatively lysogenic pathway is followed infected cell are growing slowly and MOI rate is high. They are mainly found in the centre of the plaque as they don’t have to compete with the neighbouring cells for nutrients giving it a turbid appearance. 3. When performing an experiment with the phage three dilutions are made as it reduces the density of cultures cells to more usable concentration. Each solution results in decreasing the bacteria ratio substantially giving it more accuracy in calculating a number of plaques formed on agar plate, giving hassle free and more accurate results.