Rationale: answer Lathan’s questions

1. Group 4 all had plaques on their plaque assays. Justin had the most and well defined plaque (but all 3 got plaque). They each did a spot test in addition to their plaques assays but only Justin had plaque on his spot. What do you think is going on?

Justin probably has the highest concentration of phage in his sample

2. Lathan checked a purified lysate by doing a plaque assay (10 µL of lysate) of a 10^(-3) lysate. He counted 14 plaques. How               many µL of Lathans 10^0 lysate should he add to web a plate (75 mm in diameter) if his average plaque diameter is 1mm?

( 14 pfu / 10 µL   ) * ( 1000 µL / 1 mL ) * 10^3 = 1.4×10^6 pfu/mL

Area of plate / Area of plaque = ( pi * 37.5^2 ) / (pi * 0.5^2) = 5625 pfu

5625 pfu / 1.4×10^6 pfu/mL = 0.0040 mL = 4 µL lysate